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Ghent
Ghent
International Convention Center and Ghent University - Campus Ledeganck, Ghent, Belgium
Michael Tytgat
(Ghent University (BE)),
Barbara Clerbaux
(Inter-University Institute for High Energies (BE))
Description
The European Physical Society Conference on High Energy Physics (EPS-HEP) is one of the major international conferences that reviews the field every second year since 1971 organized by the High Energy and Particle Physics Division of the European Physical Society. The latest conferences in this series were held in Venice, Vienna, Stockholm, Grenoble, Krakow, Manchester, Lisbon and Aachen.
In 2019 the EPS-HEP conference will take place in Ghent, Belgium on 10-17 July. The conference is organized by the Department of Physics and Astronomy of Ghent University in collaboration with Universiteit Antwerpen, Vrije Universiteit Brussel, Université Libre de Bruxelles and Université Catholique de Louvain.
A live broadcast for the special ECFA-EPS special session can be found on the http://eps-hep2019.eu/ page (scroll down).
General information
Participants
746
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4:00 PM
Registration International Convention Center (ICC)
International Convention Center (ICC)
Ghent
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4:00 PM
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Astroparticle Physics and Gravitational Waves Campus Ledeganck - Aud. 3
Campus Ledeganck - Aud. 3
Ghent
Conveners: Elisa Resconi (Technical University Munich), Francesca Calore (LAPTh, CNRS), Tania Regimbau-
1
High-Energy Neutrino Astronomy: Current Status and Prospects
In the last decade, neutrino astronomy has taken off and collected two major breakthroughs, the first observation of high-energy astrophysical neutrinos in 2013 and the first joint observation of gamma-rays and neutrinos (from TXS0506+056) announced last summer. In this talk, we will review these important milestones as well as the other noteworthy achievements reached by the community. We will emphasize the interest of neutrino searches in the multi-messenger era and describe the current efforts carried out in the large neutrino telescopes, with a focus on the IceCube Neutrino Observatory and KM3NeT. We will conclude presenting an outlook for the coming years.
Speaker: Gwenhaël de Wasseige (APC, CNRS) -
2
Recent highlights in high-energy-neutrino and ultra-high-energy-cosmic-ray research and implications for astrophysical candidate sources
The origin of ultra-high energy cosmic rays (UHECRs) is a long-standing mystery. In 2013 the IceCube experiment announced the observation of an astrophysical high-energy neutrino flux, adding the question of the origin of high-energy neutrinos to the mysteries in astroparticle physics. Recent highlights from the quest for the sources of UHECRs and high-energy neutrinos include the discovery of a dipole anisotropy in the arrival directions of UHECRs and the observation of high-energy neutrinos in the direction of the blazar TXS 0506+056. In this talk, I will review the implications of the most recent observations for astrophysical source models. One point of focus will be models of the origin of high-energy neutrinos in blazar flares, motivated by the first plausible association of a high-energy neutrino with an astrophysical source.
Speaker: Foteini Oikonomou (Penn State University) -
3
Detection of a Neutrino Event at the Glashow Resonance Energy in IceCube
The IceCube Neutrino Observatory has measured the astrophysical neutrino flux from tens of TeV up to PeV energies, with no significant indication of a cutoff at the highest energies. At these energies, the neutrino event-rates quickly drop and spectral measurements are statistically limited.
However, at an energy of $\approx 6.3\,$PeV, anti-electron neutrinos are expected to resonantly interact with atomic electrons via the Glashow resonance mechanism creating $W^-$-bosons, and thereby increasing the total neutrino interaction probability by two orders of magnitude. This process has so far never been experimentally observed.
Observation of Glashow resonance events would provide a unique possibility to measure the ratio of neutrinos and anti-neutrinos, which is an important input for the theoretical modelling of astrophysical accelerators.
In this talk, I will present our finding of a single partially-contained shower-like neutrino event with deposited energy $E_\text{dep} = 6.04^{+0.63}_{-0.61}\,$PeV, consistent with a neutrino interacting via the Glashow resonance.
The event shows a clear signature of relativistic muon production, consistent with a hadronic origin of the particle shower. The leading muon energy is estimated to $E_\mu=20^{+44}_{-5}\,$GeV and consistent with expectations for a hadronic W-decay with $\approx 6\,$ PeV lab-energy.
Furthermore, such an event topology is highly unlikely to arise from atmospheric background. With an estimated background rate of $10^{-7}$ in the 4.6 year search period, this strongly suggests an astrophysical origin of the neutrino.
Speaker: Christian Haack (RWTH Aachen University) -
4
Pacific Ocean Neutrino Explorer
Neutrino astronomy uses large volume detectors to search for astrophysical neutrinos. Detectors such as IceCube at the Geographic South Pole and the Gigaton Volume Detector (GVD) at Lake Baikal instrument up to a cubic kilometer of fresh water or ice for measuring Cherenkov radiation created in neutrino-matter interactions. Using the clear water of the deep sea as the Cherenkov medium has so far always posed severe difficulties in deploying and maintaining the offshore infrastructure, although KM3NeT currently develops a detector of this type in the Mediterranean.
A collaboration of the Ocean Networks Canada (ONC), the University of Victoria, the University of Alberta, and the Technical University of Munich (TUM) is currently exploring possibilities for a future neutrino telescope located in the Pacific. 300km westerly of Vicotria, the Cascadia Basin is a promising position for a cubic scale detector with a depth of 2600m. In June 2018, the collaboration deployed the Strings for Absorption Length in Water (STRAW) which monitor the optical conditions at the Cascadian Basin since then. In 2020, the deployment of STRAW-b, one 500m long string with 10 modules, is scheduled to test hardware and strategies for the 10-string array Pacific Ocean Neutrino Explorer.
We will give a brief overview and outlook of the three missions and present first results on the measurements at Cascadia Basin.
Speaker: Kilian Holzapfel (Technical University of Munich (TUM)) -
5
Recent progress of the Baikal-GVD project
Cubic kilometer scale neutrino telescope Baikal-GVD is currently under
construction in Lake Baikal. The detector is specially designed
for search for high energies neutrinos whose sources are not yet reliably
identified. Since April 2019 the telescope has been successfully
operated in complex of five functionally independent clusters i.e.
sub-arrays of optical modules (OMs) where now are hosted 1440 OMs
on 40 vertical strings. Each cluster is connected to shore by individual
electro-optical cables. The effective volume of the detector
for neutrino initiated cascades of relativistic particles with energy
above 100 TeV has been increased up to about 0.25 km$^3$.
Preliminary results in data analysis are discussed.Speaker: Olga Suvorova (Russian Academy of Sciences (RU)) -
11:00 AM
Coffe break
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6
Astrophysical Neutrinos at Hyper-Kamiokande
Hyper-Kamiokande (Hyper-K) is a proposed next generation underground large water Cherenkov detector with a 187~kton target volume of water and 40% photo coverage. With about 10 times larger fiducial volume than Super-Kamiokande, the sensitivities for astrophysical neutrinos, like solar neutrinos or supernova neutrinos, will be greatly improved in Hyper-K. In this presentation, we will discuss the physics potential of Hyper- K on astrophysical neutrinos and expected performance of the detector.
Speaker: David Bravo Berguno (Universidad Autónoma de Madrid) -
7
Searches for Nucleon Decay at Hyper-Kamiokande
While grand unified theories offer potential solutions to problems with the Standard Model, such as the origins of charge quantization, their signature prediction, proton decay, has not been observed experimentally. Hyper-Kamiokande is a next-generation water Cherenkov experiment with a 187~kton target volume that will provide unprecedented sensitivity to a variety of nucleon decay modes, including many beyond the so-called flagship modes, $p \rightarrow e^{+}\pi^{0}$ and $p \rightarrow \bar{\nu} K^{+}$.With improved detector technologies to enhance signal efficiencies and reject backgrounds, Hyper-Kamiokande is expected to search for these processes with sensitivities to proton lifetimes of 10^{35} years and longer, providing opportunities for a discoveries for lifetimes exceeding existing limits by an order of magnitude. This presentation will describe the complete Hyper-Kamiokande nucleon decay physics program and its expected sensitivities
Speaker: Hidekazu TANAKA (University of Tokyo) -
8
Atmospheric neutrino spectrum reconstruction with JUNO
The atmospheric neutrino flux represents a continuous source that can be exploited to infer properties about Cosmic Rays and neutrino oscillation physics. The JUNO observatory, a 20 kt liquid scintillator currently under construction in China, will be able to detect the atmospheric flux, given the large fiducial volume and the excellent energy resolution. The light produced in neutrino interactions will be collected by a double-system of photosensors: 18.000 x 20" PMTs and 25.000 x 3" PMTs. The rock overburden above the experimental hall is around 700 m and the experiment is expected to start the data-taking in 2021.
In this study, a sample of Monte Carlo events has been generated from theoretical models of the atmospheric neutrino flux, through the Genie software. To evaluate the JUNO performances, the events have been processed by a full Geant4 - based simulation, which propagates all the particles and the light inside the detector. The different time evolution of light on the PMTs allows to discriminate the flavor of the primary neutrinos. To reconstruct the time pattern of events, the signals from 3" PMTs only have been used, because of the small time resolution. A probabilistic unfolding method has been used, in order to infer the primary neutrino energy spectrum by looking at the detector output. JUNO will be particularly sensitive in the energy range (100-1000) MeV, where neutrino-induced events can be fully contained within the instrumented volume.Speaker: Giulio Settanta (INFN - National Institute for Nuclear Physics) -
9
ANDES: the future Latin American deep underground laboratory
In this talk I will present the project of creation of the first deep underground laboratory in the tunnel Agua Negra that will be connecting Argentina and Chile. This project profits from the construction of the highway linking two countries under the Los Andes mountain range. The depth of the tunnel provides an important cosmic ray shielding which opens vast possibilities to perform experiments in fundamental physics. The ANDES laboratory, planned as the first deep underground site in the Southern Hemisphere, will have a particular merit of providing complementary information to what is currently being learned from the existing laboratories in the Northern Hemisphere.
Speaker: Taisiya Mineeva (Universidad Técnica Federico Santa María)
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1
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Dark Matter Campus Ledeganck - Aud. 2
Campus Ledeganck - Aud. 2
Ghent
Conveners: Christian Ohm, Kalliopi Petraki (Sorbonne Université), Ranny Budnik-
10
On Anomaly-Free Dark Matter Models
Gamma lines provide a clean and distinctive signature, and hence, they represent a smoking gun for the discovery of the dark matter. Unfortunately, for many well-known dark matter models it is not possible to observe them, either because they are not predicted by the theory or they are overcome by the background. I will provide a simple guide to classify abelian dark matter models according to their potential to predict gamma lines. As an example, a very attractive and simple SM extension will be discussed: local baryon number with Majorana dark matter. In the context of this model, anomaly cancellation predicts the existence of dark matter and gamma lines, and interesting phenomenological features arise as a consequence of their leptophobic behaviour.
Speaker: Mrs Clara Murgui Galvez -
11
Robust limits on dark matter annihilation from the high latitude γ-ray sky
The Milky Way halo is the densest source of dark matter on the sky. As a matter of facts, the dark matter signals are expected to be stronger with a J-factor of ∼ 10^22 GeV2.cm−5 than those coming from objects such as dwarf galaxies (J ∼ 10^17 −10^19 GeV2.cm−5) or galaxy groups, even in regions away from the Galactic center. We present the results of an indirect search for dark matter annihilation signals in the gamma-ray data of Fermi-LAT. Our analysis is performed using 536 weeks of Pass 8 data within the energy range of 0.1 GeV - 1 TeV in the smooth Milky Way halo for the region |b|>20º and r<50º and for several annihilation channels. These results are obtained with SkyFACT, a new method of gamma-ray fitting which combines template fitting and image reconstruction and accounts for model background uncertainties. We expect to provide the most robust constraints on the annihilation cross section of dark matter at 95% C.L.
Speaker: Ms Celine Armand (LAPTh) -
12
Towards Understanding the Origin of Cosmic-Ray Positrons
Precision measurements of cosmic ray positrons are presented up to 1 TeV based on 1.9 million positrons collected by the Alpha Magnetic Spectrometer on the International Space Station. The positron flux exhibits complex energy dependence. Its distinctive properties are: (a) a significant excess starting from 25.2 GeV compared to the lower-energy, power-law trend; (b) a sharp drop-off above 284 GeV; (c) in the entire energy range the positron flux is well described by the sum of a term associated with the positrons produced in the collision of cosmic rays, which dominates at low energies, and a new source term of positrons, which dominates at high energies; and (d) a finite energy cutoff of the source term at 810 GeV is established with a significance of more than 4σ. These experimental data on cosmic ray positrons show that, at high energies, they predominantly originate either from dark matter annihilation or from other astrophysical sources.
Speaker: Nikolas Zimmermann (Rheinisch Westfaelische Tech. Hoch. (DE)) -
13
The GAPS experiment for dark matter detection with cosmic ray antinuclei.
The General Antiparticle Spectrometer (GAPS) will carry out a sensitive dark matter search by measuring low-energy (E < 0.25 GeV/nucleon) cosmic ray antinuclei. The primary target are low-energy antideuterons that might be produced in the annihilation or decay of dark matter. At these energies the antideuteron intensity from secondary/tertiary interactions is expected to be several orders of magnitude lower with respect to those predicted by beyond the standard model theories. GAPS will also conduct a low-energy antihelium search and will provide the highest-statistics spectral measurement of antiproton at these energies. Combined, these observations will provide a powerful search for dark matter and for primordial black hole evaporation.
GAPS will use a novel particle identification method based on exotic atom formation and
decay with emission of pions, protons and atomic X-rays from a common annihilation vertex.
This detection technique will give GAPS the high rejection factors necessary for rare antinuclei searches.The detector consists of a tracker, made up by ten planes of lithium-drifted silicon Si(Li) detectors, surrounded by a plastic scintillator
time-of-flight system.The first of a series of a long-duration Antarctic balloon flight is expected for the austral summer of 2020 or 2021. This presentation covers the scientific motivation for the GAPS experiment, its design and its current status.
Speaker: Riccardo Munini (INFN - Universita Studi Trieste) -
14
MADMAX: A new way to search for QCD Axion Dark Matter with a Dielectric Haloscope
Light Dark Matter candidates have increasingly come under the focus of scientific interest. In particular the QCD axion is also able to solve other fundamental problems such as CP-conservation in strong interactions. Galactic axions and axion-like particles can be converted to photons at boundaries between materials of different dielectric constants under a strong magnetic field. Combining many such surfaces, one can enhance this conversion significantly using constructive interference and resonances. The proposed MADMAX setup containing 80 high dielectric disks in a $10\,{\rm T}$ magnetic field could probe the well-motivated mass range of $40-400\,\mu{\rm eV}$, a range which is at present inaccessible by existing cavity searches. The experimental idea and the proposed design of MADMAX will be discussed. Among recent R&D results from 3D simulations and proof of principle prototype measurements, the prospects of reaching sensitivity to the QCD axion will be presented.
Speaker: Stefan Knirck (Max-Planck-Institute for Physics, Munich, Germany) -
15
Singlet-doublet fermion and triplet scalar dark matter with radiative neutrino masses
We present a detailed study of a combined singlet-doublet fermion and triplet scalar model for dark matter. These models have only been studied separately in the past. Together, they form a simple extension of the Standard Model that can account for dark matter and explain the existence of neutrino masses, which are generated radiatively. However, this also implies the existence of lepton flavour violating processes. In addition, this particular model allows for gauge coupling unification. The new fields are odd under a new Z2 symmetry to stabilise the dark matter candidate. We analyse the dark matter, neutrino mass and lepton flavour violation aspects both separately and in conjunction, exploring the viable parameter space of the model. This is done using a numerical random scan imposing successively the neutrino mass and mixing, relic density, Higgs mass, direct detection, collider and lepton flavour violation constraints. We find that dark matter in this model is fermionic for masses below about 1 TeV and scalar above. The narrow mass regions found previously for the two separate models are enlarged by their coupling. While coannihilations of the weak isospin partners are sizeable, this is not the case for fermions and scalars despite their often similar masses due to the relatively small coupling of the two sectors, imposed by the small neutrino masses. We observe a high degree of complementarity between direct detection and lepton flavour violation experiments, which should soon allow to fully probe the fermionic dark matter sector and at least partially the scalar dark matter sector.
Speaker: Michael Klasen -
11:10 AM
Coffee break
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16
Status and Results from the XENON Dark Matter Project
XENON1T, the first tonne-scale dual-phase xenon time projection chamber, took data at the Laboratori Nazionali del Gran Sasso in Italy between 2016 and 2018. The experiment was sensitive to the scattering of weakly interacting massive particle (WIMP) dark matter within a 2 t target volume. By using both the scintillation and ionisation signals induced by an interaction it is possible to discriminate WIMP-induced events from the main electronic recoil background. The electronic-recoil background rate of 82 ev / (t yr keV) is the lowest ever achieved in such a detector.
Work is now underway to upgrade the detector to XENONnT. Using much of the same infrastructure, this will have a three-times larger target. At the same time XENONnT will have a significantly reduced background rate, largely due to a new radon distillation column.
This talk will present the latest results from XENON1T as well as the status of the XENONnT work currently being performed.Speaker: Adam Brown (University of Zurich) -
17
Dark matter search results from 231 live-days of DEAP-3600
DEAP-3600 is a dark matter detector located 2 km underground at SNOLAB. The DEAP-3600 detector is sensitive to the scintillation signal from the scattering of dark matter particles on argon nuclei, using a single-phase (scintillation-only) design. The 3279 kg LAr target is contained in a spherical acrylic vessel and viewed by 255 photomultiplier tubes. The background from Ar-39 beta decays is strongly suppressed by the best pulse-shape discrimination in a LAr detector demonstrated so far. This talk will highlight the recent analysis and results from 231 live-days of data in DEAP-3600, currently representing the most sensitive WIMP search above a mass of 30 GeV/c2 using argon.
Speaker: Dr Tina Pollmann (Technische Universität München) -
18
DarkSide-50 Results and the Future Liquid Argon Dark Matter Program
DarkSide uses a dual-phase Liquid Argon Time Projection Chamber to search for WIMP dark matter. The talk will present the latest result on the search for low mass ($M_{WIMP} <20GeV/c^2$ ) and high mass ($M_{WIMP}>100GeV/c^2$) WIMPs from the current experiment, DarkSide-50, running since mid 2015 a 50-kg-active-mass TPC, filled with argon from an underground source. The next stage of the DarkSide program will be a new generation experiment involving a global collaboration from all the current Argon based experiments.
DarkSide-20k, is designed as a 20-tonne fiducial mass TPC with SiPM based photosensors, expected
to be free of any instrumental background for an exposure of >100 ton x years. Like its predecessor DarkSide-20k will be housed at the Gran Sasso (LNGS) underground laboratory, and it is expected to attain a WIMP-nucleon cross section exclusion sensitivity of $10^{-47}\, cm^2$ for a WIMP mass of $1 TeV/c^2$ in a 5 yr run.
A subsequent objective, towards the end of the next decade, will be the construction of the ultimate
detector, ARGO, with a 300 t fiducial mass to push the sensitivity to the neutrino floor region for high mass WIMPs.
The combination of the three experiments, part of a single family, will cover completely the WIMP hypothesis from 1GeV/c2 to several hundreds of TeV/c2 masses.Speaker: Alessio Caminata (INFN e Universita Genova (IT)) -
19
DARWIN – a next-generation liquid xenon observatory for dark matter and neutrino physics
Benefiting from more than a decade of experience in WIMP search with liquid xenon time projection chambers, the DARWIN (DARk matter WImp search with liquid xenoN) collaboration intends to build an observatory involving 50 tonnes of xenon. The primary goal of the experiment is to explore the entire experimentally accessible parameter space for WIMP masses above ${5} \ \mathrm{GeV/c^2}$ down to the irreducible neutrino floor. With its low energy threshold and ultra-low background level, DARWIN will provide an excellent platform to search for various other rare interactions, including the neutrinoless double beta decay of $^{136}\mathrm{Xe}$, solar axions and axion-like particles. Furthermore, it will measure the low-energy solar neutrino flux with high precision, observe coherent neutrino-nucleus interactions and detect galactic supernovae. In this talk, we will present the detector concept, the sensitivity to the various science channels, and ongoing R&D efforts.
Speaker: Mr Kevin Thieme (University of Zurich)
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10
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Detector R&D and Data Handling Campus Ledeganck - Aud. 4
Campus Ledeganck - Aud. 4
Ghent
Conveners: Nadia Pastrone (INFN), Niko Neufeld (CERN)-
20
Precision Timing with the CMS MIP Timing Detector
The Compact Muon Solenoid (CMS) detector at the CERN Large Hadron Collider (LHC) is undergoing an extensive Phase II upgrade program to prepare for the challenging conditions of the High-Luminosity LHC (HL-LHC). In particular, a new timing layer with hermetic coverage up to a pseudo-rapidity of |η|=3 will measure minimum ionizing particles (MIPs) with a time resolution of ~30ps. This MIP Timing Detector (MTD) will consist of a central barrel region based on LYSO:Ce crystals read out with SiPMs and two end-caps instrumented with radiation-tolerant Low Gain Avalanche Detectors. The precision time information from the MTD will reduce the effects of the high levels of pile-up expected at the HL-LHC and will bring new and unique capabilities to the CMS detector. The time information assigned to each track will enable the use of 4D reconstruction algorithms and will further discriminate interaction vertices within the same bunch crossing to recover the track purity of vertices in current LHC conditions. For instance, in the analysis of di-Higgs boson production decaying to two b quarks and two photons, 30 ps timing resolution is expected to improve the effective luminosity by 22% through gains in b-tagging and photon isolation efficiency. We present motivations for precision timing at the HL-LHC and the ongoing MTD R&D targeting enhanced timing performance and radiation tolerance.
Speaker: Adolf Bornheim (California Institute of Technology (US)) -
21
A High-Granularity Timing Detector for the Phase-II upgrade of the ATLAS Calorimeter system: detector concept, description and R&D and first beam test results
The increase of the particle flux (pile-up) at the HL-LHC with luminosities of L ≃ 7.5 × 1034 cm−2 s-1 will have a severe impact on the ATLAS detector reconstruction and trigger performance. The end-cap and forward region where the liquid Argon calorimeter has coarser granularity and the inner tracker has poorer momentum resolution will be particularly affected. A High Granularity Timing Detector (HGTD) is proposed in front of the LAr end-cap calorimeters for pile-up mitigation and for luminosity measurement.
It will cover the pseudo-rapidity range from 2.4 to 4.0. Two Silicon sensors double sided layers will provide precision timing information for MIPs with a resolution better than 30 ps per track in order to assign each particle to the correct vertex. Readout cells have a size of 1.3 mm × 1.3 mm, leading to a highly granular detector with 3 millions of channels. Low Gain Avalanche Detectors (LGAD) technology has been chosen as it provides enough gain to reach the large signal over noise ratio needed.
The requirements and overall specifications of the HGTD will be presented as well as the technical proposal. LGAD R&D campaigns are carried out to study the sensors, the related ASICs, and the radiation hardness. Laboratory and test beam results will be presented.
Speaker: Alexander Leopold (LPNHE Paris) -
22
SciFi - A large Scintillating Fibre Tracker for LHCb
The LHCb detector is currently being upgraded in order to cope with higher instantaneous luminosities and to read out the data at 40MHz using a trigger-less read-out system. The Run 1 + 2 tracking system, composed of an inner and outer tracking detector, will not be able to cope with the increased particle multiplicities and is being replaced by a single homogenous detector based on scintillating fibres. The new Scintillating Fibre (SciFi) Tracker covers a total detector area of 340 m2 and should provide a spatial resolution for charged particles better than 100 µm in the bending direction of the LHCb spectrometer. The detector is being built from individual modules (0.5 m × 4.8 m), each comprising 8 scintillating fibre mats with a length of 2.4 m as active detector material. The fibre mats consist of 6 layers of densely packed blue emitting scintillating fibres with a diameter of 250 µm. The scintillation light is recorded with arrays of state-of-the-art multi-channel silicon photomultipliers (SiPMs). A custom ASIC will be used to digitize the SiPM signals. Subsequent digital electronics performs clustering and data-compression before the data is sent via optical links to the DAQ system. To reduce the thermal noise of the SiPM in particular after being exposed to a neutron fluence of up to 1012 neq /cm2, expected for the lifetime of the detector, the SiPMs arrays are mounted in so called cold-boxes and cooled down by 3D-printed titanium cold-bars to -40o C. Modules together with cold-boxes and readout electronics are mounted on so-called C-frames which provide the mechanical support structure and the necessary services to power, read out and cool the detector elements. After a first proto-type frame has been built and tested the serial assembly of these detector elements has started in March 2019. The first finished and commissioned detector elements will be installed in the experimental cavern at the end of 2019. The talk will give an overview of the detector concept and will present the experience from the series production complemented by most recent test and comissioning results.
Speaker: Mauricio Feo (Nikhef National institute for subatomic physics (NL)) -
23
The new Inner Tracking System for the ALICE Upgrade
ALICE (A Large Ion Collider Experiment) is the CERN LHC experiment optimized for the study of the strongly interacting matter produced in heavy-ion collisions, in particular the characterization of the quark-gluon plasma. ALICE is preparing a major upgrade of its detector to be installed during the second long LHC shutdown (LS2). The main objective is to increase the readout capabilities to allow the readout and recording of Pb–Pb minimum bias events at rates in excess of 50 kHz, the expected Pb–Pb interaction rate at the LHC after LS2. This increase in readout speed, together with the deployment of a new data acquisition system capable of recording all collisions, will imply an increase by about two orders of magnitude in the collectible minimum-bias statistics compared to the present ALICE set-up. One of the key components of the LS2 upgrade programme is the replacement of the current Inner Tracking System (ITS) with an entirely new one (ITS2) which will bring about an increased vertexing and tracking performance, especially for particles with low transverse momentum ($p_{\rm T}$ < 1 GeV/c). The new ITS consists of seven approximately-cylindrical detector layers based on CMOS Monolithic Active Pixel Sensors (MAPS) with the sensor matrix and readout integrated in a single chip, named ALPIDE (ALice PIxel DEtector), covering a 10 m$^2$ area with about 12.5 billion pixels. This talk will present the motivations, the requirements and the overall layout of the ITS2 as well as the construction and commissioning status.
Speaker: Dr Yasser Corrales Morales (Los Alamos National Laboratory (US)) -
24
The Gigatracker of the NA62 experiment at CERN
NA62 is a fixed-target experiment at the CERN SPS designed to measure the branching ratio of the very rare kaon decay $K^{+}\rightarrow \pi^{+} \nu \bar{\nu}$ with 10% precision. Measurements of time, momentum and direction of incoming beam particles are provided by a beam spectrometer called GigaTracKer.
The GigaTracKer is made of three stations of hybrid silicon pixel detector installed in vacuum ($\sim$10-6mbar). Each station consists of 18000 pixels of $300\times300\mu m^{2}$ area each, arranged in a matrix of $200\times90$ elements corresponding to a total area of $62.8\times27mm^{2}$. The beam particles, flowing at 750 MHz, are tracked in 4-dimensions by means of time-stamping pixels with the single hit time resolution reaching 115ps. This performance has to be maintained despite the beam irradiation amounting to a yearly fluence of $4.5 \times 10^{14}\ 1MeV\ n_{eq}/cm^{2}/200\ days$. In order to limit multiple scattering and beam hadronic interactions, the station material budget is reduced to 0.5%X0 by using micro channel cooling (first application in HEP).
We will present the detector design and performances during the NA62 data taking periods.
Speaker: Alina Kleimenova (Universite Catholique de Louvain (UCL) (BE)) -
25
Commissioning of the Belle II Pixel Vertex Detector
As an upgrade of the asymmetric e+e− collider KEKB, SuperKEKB aims to increase the peak luminosity by a factor of 40 to 8×10^35 cm^−2s^−1. The upgraded Belle II detector allows the experiment to handle the much increased data rates, with the goal to explore new physics beyond the Standard Model at the intensity frontier. Belle II is expected to accumulate a dataset of 50 ab^−1 by 2027. The Belle II pixel detector (PXD) has been developed using the DEpleted P-channel Field Effect Transistor (DEPFET) technology, which combines low power consumption in the active pixel area and low intrinsic noise with a very small material budget. In this talk commissioning and performance of this novel detector measured with first collision data will be presented.
Speakers: Dr Hua Ye, PXD-DEPFET Collaboration -
26
Upgrade of the ALICE Time Projection Chamber for the LHC Run3
One of the experiments at the Large Hadron Collider (CERN), ALICE, is undergoing ambitious upgrades during the ongoing second long shutdown. The main goal of this project is to accessrare events and previously inaccessible physics observables. The increased Pb-Pb and p-p collision rates need a correspondingly higher TPC operation rate in the next Run 3 of the LHC.
The operational gated MWPC readout used so far cannot be used at such fast rates. Therefore a new readout chamber is needed with a novel technology and without any compromise on the momentum and energy resolution. As a solution the Gas Electron Multiplier (GEM) technology is applied, which is a thin, metal-clad polymer foil with a high density of holes etched chemically. This new readout chamber consists of inner- (IROC) and outer (OROC) readout chambers with a 4 stage
GEM cascade in order to reduce back-drifting ion space charges. These quadruple stacks have proven to provide sufficient ion blocking capabilities. This structure also preserves the intrinsic energy resolution and keeps the space-charge distortions at a tolerable level. At the nominal working point, the gain of one stack is around 2000.We will present the status of the ongoing ALICE TPC upgrade project: (i) The recently completed quality assurance (QA) and calibration of the 720 GEM foils. This included basic QA tests performed at CERN, a high definition optical and gain scan. (ii) The disassembly and re-build of the ALICE TPC. (iii) The new data acquisition with continuous readout system for the 50kHz Pb-Pb performance.
Speaker: Adam Laszlo Gera (Hungarian Academy of Sciences (HU)) -
27
Status of the TORCH time-of-flight detector
TORCH is a novel time-of-flight detector, designed to provide $\pi$/K particle identification up to 10 GeV/$c$ momentum over a 10 m flight path. Based on the DIRC principle, Cherenkov photons are produced in a quartz plate of 10 mm thickness, where they propagate to the periphery of the plate by total-internal reflection. There the photons are focused onto an array of micro-channel plate photomultipliers (MCP-PMTs) which measure their arrival times and spatial positions. A time resolution of 70 ps per detected Cherenkov photon is expected, which results in a time-of-flight resolution of 15 ps, given typically 30 detected photons per track. To demonstrate the principle, a half-scale ($660\times1250\times10$ mm$^3$) TORCH prototype module has been tested in a 5 GeV/$c$ mixed proton-pion beam at the CERN PS. Customised $53\times53$ mm$^2$ MCP-PMTs of effective granularity $128\times8$ pixels have been employed, which have been developed in collaboration with an industrial partner. The single-photon timing performance and photon yields have been measured and are close to specification, demonstrating the TORCH concept. For a future application, a full-scale TORCH detector has been proposed for the LHCb Phase II Upgrade, which comprises 18 modules with 198 MCP-PMTs. Results will be reported on the simulated performance of the detector for high luminosity LHCb running in terms of $\pi$/K/p discrimination.
Speaker: Tom Hadavizadeh (University of Oxford (GB)) -
11:00 AM
Coffee break
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28
First Experiences with the Novel Time of Propagation (TOP) Barrel PID Detector in the Belle II Experiment
The Time of Propagation (TOP) detector is a novel particle identification system developed for the barrel region of the Belle II experiment at the SuperKEKB collider at KEK in Tsukuba, Japan. The detector is based on reconstructing the emission angle of Cherenkov photons generated in its quartz radiator bars by measuring the propagation time of individual photons to the Micro-Channel Plate PMT sensor plane. The readout electronics for the 8192 channels of the TOP system are built around a switched capacitor array waveform sampling ASIC operating at 2.7GSa/s. Acquired waveforms are processed in real time in the front end electronics, extracting the individual timing of detected photons to better than 100 ps.
After a commissioning run with first beam collisions starting in spring 2018, the final inner tracking system is now installed in the Belle II detector, and the physics programme and luminosity rampup is underway since March 2019.
This talk presents the current experiences and results from commissioning, calibration and operation of the Belle II TOP detector in the first Belle II physics runs up until now.
Speaker: Oskar Hartbrich (University of Hawaii at Manoa) -
29
MUON Spectrometry at forward rapidities in ALICE
ALICE is the experiment specifically designed for the study of the Quark-Gluon Plasma in heavy-ion collisions at the CERN LHC. The forward Muon Spectrometer of ALICE is devoted to the study of muon production in the pseudo-rapidity interval between 2.5 and 4. During Run 1 and 2, the spectrometer produced an impressive amount of results concerning the Quarkonia (J/$\Psi$ and $\Upsilon$ families), Heavy flavor and low mass vector mesons. The present spectrometer is composed of two systems: the muon tracking based on 10 planes of Cathode Pad Chambers (CPC) and the muon trigger based on 4 planes of Resistive Plate Chambers (RPC). For Run 3 and 4, an ambitious upgrade program is ongoing for both systems, consisting of the replacement of the front-end and the back-end readout electronics in order to cope with an increased rate by an order of magnitude in Pb-Pb collisions compared to run 2. An additional detector, the Muon Forward Tracker (MFT), will be installed in front of the spectrometer absorber. It consists of planes of high resolution CMOS pixel sensors and it will bring precise vertexing capabilities to the Muon Spectrometer. The technical challenges and construction status related to the muon spectrometer upgrade and the addition of the MFT will be presented.
Speaker: Andrea Ferrero (Université Paris-Saclay (FR)) -
30
Frontend and backend electronics for the ATLAS New Small Wheel Upgrade
The Phase-I and Phase-II upgrades of the LHC accelerator will increase the LHC instantaneous luminosity to 2×1034 cm−2s−1 and 7.5×1034 cm−2s−1, respectively. The luminosity increase drastically impacts the ATLAS trigger and readout data rates. The present ATLAS small wheel muon detector will be replaced with a New Small Wheel (NSW) detector in 2019. The NSW will feature two new detector technologies, Resistive Micromegas (MM) and small strip Thin Gap Chambers (sTGC) conforming a system of ~2.4 million readout channels. Both detectors will be used for muon triggering and precision tracking. A common readout path and two separate trigger paths are developed for these two detector technologies. The frontend electronics will be implemented in about 8000 boards including the design of 4 custom ASICs capable of driving trigger and tracking primitives to the backend trigger processor and readout system. The readout data flow is designed through a high-throughput network approach. The large number of readout channels, short time available to prepare and transmit trigger data, large volume of output data, harsh radiation environment, and the need of low power consumption all impose great challenges on the system design. We will present the overall design along with the status of all ASIC and board prototypes.
Speaker: Ann Miao Wang (Harvard University (US)) -
31
The GEM (GE1/1) Phase II Upgrade for the CMS muon system: results from in-situ demonstrator, production detector qualification, and commissioning plans
In the next years the Large Hadron Collider (LHC) will be upgraded to significantly expand its physics program, increasing the luminosity up to 5 × 10^34cm^−2s^−1, well beyond the design value. An upgrade of the CMS detector is needed accordingly to cope with the expected growth in background rates, with the goal of keeping a high trigger efficiency. In this context, a first new station called GE1/1 will be installed in 2019-2020 in the CMS muon system. It will be composed by 144 Triple Gas Electron Multiplier (GEM) detectors to be integrated in the CMS muon endcaps in the region closest to the beam line. A fundamental operational experience has been already achieved in 2017-2018, when a demonstrator composed of ten GE1/1 Triple-GEM detectors was installed to prove the integration of the GE1/1 system into CMS itself. In parallel, a dedicated production chain has been setup in seven production sites spread around the world, for the construction and qualification of all the detectors for the complete station. This contribution will give a complete overview of the GE1/1 project: the detectors design and performance will be discussed, together with the lessons learned from the GE1/1 demonstrator installation, integration and operation. The construction and qualification processes will be presented, with great emphasis to the results obtained with the 144 GE1/1 detectors. Finally, the plans for the installation and commissioning of the full station will be outlined.
Speaker: Ilaria Vai (Universita and INFN (IT)) -
32
The CMS Tracker Upgrade for the High Luminosity LHC
The LHC machine is planning an upgrade program which will smoothly bring the luminosity to about $5-7.5\times10^{34}$cm$^{-2}$s$^{-1}$ in 2028, to possibly reach an integrated luminosity of $3000-4500\;$fb$^{-1}$ by the end of 2039. This High Luminosity LHC scenario, HL-LHC, will require an upgrade program of the LHC detectors known as Phase-2 upgrade. The current CMS Outer Tracker, already running beyond design specifications, and CMS Phase-1 Pixel Detector will not be able to survive HL-LHC radiation conditions and CMS will need completely new devices, in order to fully exploit the highly demanding conditions and the delivered luminosity. The new Outer Tracker should have also trigger capabilities. To achieve such goals, R\&D activities have explored options for both the Outer Tracker and for the Inner Tracker. The solutions developed will allow to include tracking information in the first level trigger stage. The design choices for the Tracker upgrades are discussed along with some highlights on technological approaches and R\&D activities.
Speaker: Simone Paoletti (Universita e INFN, Firenze (IT)) -
33
The FAMU experiment at RIKEN RAL for a precise measure of the proton radius
The FAMU (Fisica degli Atomi Muonici) experiment has the goal to measure precisely the proton Zemach radius, thus contributing to the solution of the so-called proton radius ``puzzle'', consisting in a 6 sigmas discrepancy between measurements with electrons and with muons of the charge proton radius. This discrepancy may point to new physics or violation of the lepton universality. To this aim, the FAMU experiment makes use of a high-intensity pulsed muon beam at RIKEN-RAL impinging on a cryogenic hydrogen target with an high-Z gas admixture and a tunable mid-IR high power laser, to measure the hyperfine (HFS) splitting of the 1S state of the muonic hydrogen. From the value of the exciting laser frequency, the energy of the HFS transition may be derived with high precision ($\sim 10^{-5}$) and thus, via QED calculations, the Zemach radius of the proton. The experimental signature of the process will be the emission of characteristic X-rays ($\sim$ 100 keV) from the de-excitation of the high-Z muonic atoms formed when the muon is transferred from $\mu p$ to $\mu Z$. Preliminary studies have provided indications on the most suitable high-Z elements to be used. The experimental apparatus includes a system of precise fiber-SiPM beam hodoscopes, a crown of eight 1" $LaBr_3$ crystals read by photomultipliers complemented by additional 1/2" $LaBr_3$ crystals read by SiPM arrays with temperature control and a few HPGe detectors for detection of the emitted characteristic X-rays around 100 keV . The system is in condition to detect the signal in a very noisy environment and has been used for preliminary runs. The experimental apparatus and the innovative method to determine the Zemach proton radius with high precision will be described in detail.
Speakers: Maurizio Bonesini, Maurizio Bonesini (Universita & INFN, Milano-Bicocca (IT)), Maurizio Bonesini
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20
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Flavour Physics and CP Violation Campus Ledeganck - Aud. 6
Campus Ledeganck - Aud. 6
Ghent
Conveners: Admir Greljo, Angela Papa, Mitesh Patel (Imperial College (GB))-
34
First look at CKM parameters from early Belle II data
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is $8\times 10^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of data, a factor of 50 more than its predecessor. From February to July 2018, the machine has completed a commissioning run, achieved a peak luminosity of $5.5\times 10^{33}$ cm$^{-2}$s$^{-1}$, and Belle II has recorded a data sample of about 0.5 fb$^{-1}$. Main operation of SuperKEKB has started in March 2019.
We use the early Belle II data to characterize the performance of the detector regarding the tracking of charged particles, the reconstruction of known resonances, and the capability of identifying displaced decay vertices.
A first benchmark towards analysing time-dependent CP violation consists in the measurement of the lifetime of B mesons and of the $B^0-\bar B^0$ mixing frequency. We present the first results, based on samples of B mesons that decay to hadronic and semileptonic final states. We further present estimates of the sensitivity to $\beta$ in the golden channels $B\to c\bar cs$ and in the penguin-dominated modes $B^0\to\eta’ K^0$, $\phi K^0$, $K_S\pi^0(\gamma)$. A study of the time-dependent analysis of $B^0\to\pi^0\pi^0$, relevant for the measurement of $\alpha$, and feasible only in the clean environment of an $e^+ e^-$ collider, will also be given.
Belle II can also measure $\gamma$, the third and least well known CKM angle, through the interference between $B^+\to D^0 K^+$ and $B^+ \to \bar D^0 K^+$ decays, which occurs if the final state of the charm-meson decay is accessible to both the $D^0$ and $\bar D^0$ mesons. We will also discuss the precision that Belle II will be achieved in this measurement.
Speaker: Isabelle Ripp-Baudot (CNRS) -
35
Measurements of the CP violation phase phi_s at LHCb
Decays of the Bs meson via b->ccbars transitions are excellent probes for physics beyond the Standard Model due to their sensitivity to the CP-violating phase phi_s. In addition, the Bs decay width and the decay width difference between the Bs mass eigenstates are measured precisely in these modes. We present the first Run 2 measurements of these quantities at LHCb.
Speaker: Veronika Georgieva Chobanova (Universidade de Santiago de Compostela (ES)) -
36
Measurement of the weak mixing phase phi_s through time-dependent CP violation in Bs0—>J/psi phi decay in ATLAS
In the Standard Model of particle physics, CP violation arises due to a single complex phase in the Cabibbo–Kobayashi–Maskawa (CKM) quark mixing matrix. Testing the validity of the CKM mechanism as the only source of CP violation is one of the major experimental challenges in particle physics today. Precise measurement of the CKM parameters therefore constrains the Standard Model, and may reveal effects beyond the Standard Model. Measurement of the time–dependent decay rates of Bs0—>J/psi phi provides a theoretically clean method for extracting CP–violating weak mixing phase phi_s. The Standard Model predicts phi_s to be very small and it is very well constrained, while in many new physics models large phi_s values are expected. Bs0—>J/psi phi decay channel is sensitive to the new physics contributions, and already small deviations in a measurement of phi_s would be hints for the existence of the new particles.
The most recent results from ATLAS are presented in CP-violating mixing phase phi_s and several other parameters describing the Bs0 meson system.Speaker: Adam Edward Barton (Lancaster University (GB)) -
37
Searches for direct CP violation in two-body and quasi-two-body B meson decays at LHCb
B meson decays with contributions from loop processes give access to physics within and beyond the Standard Model through measurements of their CP-violating parameters and branching fractions. We present the latest LHCb results of direct CP violation searches in B meson decays using a two-body approximation.
Speaker: Tom Hadavizadeh (University of Oxford (GB)) -
38
Time-integrated measurements of the CKM angle gamma
The tree-level determination of the CKM angle gamma is a standard candle measurement of CP violation in the Standard Model. The latest LHCb results from time-integrated measurements of CP violation using beauty to open charm decays are presented. These include updates to previous Run 1 measurements, and new results from processes that have never been studied before, using the LHCb Run 2 data sample.
Speaker: Ms Alexandra Paige Rollings (University of Oxford (GB)) -
39
First measurements of the phi_3 sensitive decay B+ -> D(Ks pi+ p- pi0) K+ with Belle
We present the first model-independent measurement of the CKM angle $\phi_3$ using $B^{\pm}\to D(K_{\rm S}^0\pi^+\pi^-\pi^0)K^{\pm}$ decays. The GGSZ method is used by binning the a five-dimensional phase space of the $D$ decay. This analysis uses the measurement of the average strong-phase differences across the phase space in $D \to K_{\rm S}^0\pi^+\pi^-\pi^0$ decays from CLEO-c, as input. The results are obtained from the full Belle data set with an integrated luminosity of 711 fb$^{-1}$ collected at the $\Upsilon(4S)$ resonance.
Speaker: Resmi P K (IIT Madras) -
40
Time-dependent CP violation measurements from beauty to open charm decays
The latest time-dependent CP violation measurements using beauty to open charm decays from LHCb are presented. These decays provide sensitivity to important CKM parameters such as the angles beta and gamma from the unitarity triangle. Measurements include the latest results from new decay channels, analysed for the first time, including data from both LHCb Run 1 and Run 2.
Speaker: Sevda Esen (Nikhef National institute for subatomic physics (NL)) -
11:10 AM
Coffee break
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41
Time-dependent CP violation in charmless b decays at LHCb
In the B meson sector, measurements of weak phases not associated with Vub are obtained through time-dependent, flavour-tagged analyses involving B-Bbar mixing. In addition to new phases that may enter the mixing loop, charmless B decays have an additional mechanism for unknown particles to induce deviations from the Standard Model expectation due to the sizeable contribution to these decays from penguin topologies. We present the most recent studies of time-dependent CP violation in charmless B decays at the LHCb experiment, including Bs -> phi phi, one of the “golden channels” for New Physics searches.
Speaker: Louis Henry (Instituto de Física Corpuscular (IFIC)) -
42
Observation of several sources of CP violation in B+ -> pi+ pi+ pi- decays at LHCb
Very large CP asymmetries in decays of B mesons to final states containing three charged particles have been observed and attracted much interest. We present new results from a Dalitz plot analysis of B -> 3pi using a data sample corresponding to an integrated luminosity of 3 fb-1 of pp collisions recorded by the LHCb detector. Significant CP violation from different sources (S-wave, D-wave,S-P wave interference etc.) are established and may shed new light on understanding the underlying dynamics for CP violation in hadronic B decays.
Speaker: Jeremy Peter Dalseno (Universidade de Santiago de Compostela (ES)) -
43
CP violation in multi-body charmless b-hadron decays at LHCb
Long-distance resonant dynamics along with a sizeable weak phase present in multi-body charmless b-hadron decays leads to a rich structure of CP violation as a function of the phase space. Amplitude analysis provides a deeper understanding of the mechanisms that generate strong phase variations, which are responsible for this effect. We present the amplitude analyses of B+ -> pi+ K+ K- and Bs -> Ks K± pi∓. For the former, CP asymmetries of the contributing quasi-two-body resonances are measured.
Charmless b-baryon decays represent a promising opportunity to make a first observation of CP violation in the baryonic sector. We also present the most recent measurements of four-body charmless b-baryon decays performed by LHCb.Speaker: Adam Morris (Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France) -
44
Time-dependent CP violation in B decays at Belle
Using the entire Belle dataset collected at the Upsilon(4S) resonance containing 772 million B-meson pairs, measurements of time-dependent CP violation in neutral B meson decays are performed for the decay channels governed by, or sensitive to, the b → s penguin (loop) transitions. In this presentation, we report a new measurement of CP violation parameters in B → Ks Ks Ks and few other channels.
Speaker: Yosuke Yusa
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34
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Heavy Ion Physics ICC - Baeckeland 1
ICC - Baeckeland 1
Ghent
Conveners: Guilherme Milhano (LIP-Lisbon & CERN TH), Iwona Grabowska-Bold (AGH University of Science and Technology (PL)), Yen-Jie Lee (Massachusetts Institute of Technology), You Zhou (University of Copenhagen (DK))-
45
System and event activity dependences of inclusive jet production with ALICE
Jets are produced by a high momentum transfer of initial partons at high energies. Comparing jet production in pp and nucleus-nucleus collisions will allow us to study the jet-quenching effect caused by the hot and dense QCD medium produced in nucleus-nucleus collisions when energetic partons traverse the medium. In particular, systematic studies of jet production in different multiplicity environments will provide in-depth understanding of the medium properties and its evolution from small to large systems. In small systems and high multiplicity events, the particle bulk behaves as if a hot QCD medium was created, but such behavior is not observed with hard probes. Therefore, a detailed study of the jet production in different collision systems and different event activity with various jet resolution parameters will help us to investigate further the existence of medium effects on jets in small systems with high multiplicity. In this presentation, the jet cross section measurements in different collision systems using the data taken by ALICE during the LHC RUN 2 will be presented. The jet nuclear modification factor, which characterizes the jet-quenching effect, will be presented using different jet resolution parameters. In order to study the jet collimation properties, the jet cross section ratio for different jet resolution parameters will be also measured and compared to different theoretical models.
Speakers: Daicui Zhou (Central China Normal University CCNU (CN)), Yongzhen Hou (Central China Normal University CCNU (CN)) -
46
Jet Measurements in Heavy Ion Collisions with the ATLAS Experiment
This talk presents the latest jet measurements in 5.02 TeV Pb+Pb collisions with the ATLAS Experiment at the LHC. Jets are direct probes of the quark-gluon plasma produced in heavy-ion collisions and studying how they are modified in the heavy-ion collisions compared to the pp collisions provides insight into their interactions with this QCD medium. The latest jet results from ATLAS shown in this talk include measurements of nuclear modification factor of jets, jet fragmentation functions, the momentum and angular dependence of charged particle yields within and around jets, and the correlations of jets with direct photons. The presented measurements are also directly compared to state of the art theoretical models and provide important information to understand the strength and mechanism of the jet quenching. Further, this talk presents ATLAS results on dijet production in p+Pb collision that help to understand the partonic structure of heavy nuclei, and serve as a constraint on the initial state of Pb+Pb collisions.
Speaker: Helena Santos (LIP - Lisbon) -
47
Broadening and saturation effects in dijet azimuthal correlations in p-p and p-Pb collisions at √sNN= 5.02 TeV
We demonstrate that the recent forward-forward dijet correlation data measured by the ATLAS collaboration for proton-proton and proton-lead collisions are consistent with the broadening effects due to both the gluon saturation and the resummation of large logarithms of the hard scale (the so-called Sudakov logarithms). We find that both effects are necessary to describe the experimental results.
Speaker: Krzysztof Kutak (Instytut Fizyki Jadrowej Polskiej Akademii Nauk) -
48
Time evolution of a medium-modified jet
The presence of a hot and dense medium, produced in ultra-relativistic heavy-ion collisions, is known to modify the parton shower evolution. Several observations of the resulting intra-jet activity show significant modifications of what can be considered as a medium-modified jet from a “vacuum” (proton-proton) reference. These modifications, generically known as jet quenching effects, are the result of the multiple interactions of the parton shower with the produced fast evolving quark-gluon plasma (QGP). Recent efforts have tried to assess the time dependence of jet quenching effects, with particular focus on late [1] or early dynamics [2]. In this talk, we show a novel tool that evaluates the full-time evolution of the jet, by applying jet grooming techniques to a fully re-clustered jet. The result can bring novel insights into the QGP expansion as well as shed some light on how to re-sum, in a consistent way, vacuum-like and medium-like emissions into a single parton shower evolution equation.
[1] L. Apolinário, G. Milhano, C. Salgado, G. Salam, arXiv:1711.03105
[2] C. Andrés, N. Armesto, H. Niemi, R. Paatelainen, C. Salgado, arXiv:1902.03231Speaker: Liliana Apolinario (LIP (PT)) -
49
Recent jet results in heavy-ion collisions with CMS
The quenching of jets in heavy-ion collisions probes the transport properties of the quark-gluon plasma. We present selected recent inclusive jet and photon+jet measurements from the CMS experiment.
Speaker: Inna Kucher (Centre National de la Recherche Scientifique (FR)) -
50
Relating CGC and TMD factorization frameworks beyond leading twist
It is known already for some time that the leading power limit of the Color Glass Condensate (CGC) expressions for dijet production can be identified with the (generalized) Transverse Momentum Dependent (TMD) factorization in the small x regime. In the latter formalism, there are several TMD gluon distributions containing distinct Wilson line operators, and corresponding on-shell hard factors. There is a natural extension of this formalism, which generalizes the on-shell hard factors to the off-shell case in a gauge invariant way -- the so-called small-x improved TMD factorization (ITMD) [JHEP 1509 (2015) 106], which allows to study the kinematic regime beyond back-to-back configuration, and thus beyond the leading twist. In a recent work [arXiv:1901.01175] we studied the relation of the ITMD approach and the CGC theory in detail. We have shown that the ITMD framework corresponds to isolated and resummed all kinematic twists in the CGC theory.
Speaker: Piotr Kotko (Penn State University) -
51
Machine Learning based jet momentum reconstruction in Pb-Pb collisions measured with ALICE
The precise reconstruction of jet transverse momenta in heavy-ion collisions is a challenging task. A major obstacle is the large number of uncorrelated (mainly) low-$p_{\rm T}$ particles overlaying the jets. Strong region-to-region fluctuations of this background complicate the jet measurement and lead to significant uncertainties.
We developed a novel approach to correct jet momenta (or energies) for the underlying background in heavy-ion collisions. The approach allows the measurement of jets down to extremely low transverse momenta and for large resolution R by making use of common Machine Learning techniques to estimate the jet transverse momentum based on several parameters.In this talk, we will present transverse momentum spectra and nuclear modification factors of track-based jets that have been corrected by this Machine Learning approach and comparisons to published results where possible. The analysis was performed on Pb-Pb collisions at $\sqrt{s_{NN}} = 5.02$ TeV recorded with the ALICE detector and measures jets with large resolution parameters for low momenta, unprecedented thus far in data on heavy-ion collisions.
Speaker: Rudiger Haake (Yale University (US)) -
11:10 AM
Coffee break
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52
On the pair correlations of neutral $K, D, B$ and $B_s$ mesons with close momenta produced in inclusive multiparticle processes
The phenomenological structure of inclusive cross-sections of the production of two neutral $K$ mesons in hadron--hadron, hadron--nucleus and nucleus--nucleus collisions is theoretically studied taking into account the strangeness conservation in strong and electromagnetic interactions. Relations for the dependence of correlations of two short-lived and two long-lived neutral kaons
$K^0_S K^0_S$, $K^0_L K^0_L$ and correlations of "mixed" pairs $K^0_S K^0_L$ at small relative momenta upon the space-time parameters of the generation region of $K^0$ and $\bar{K}^0$ mesons are obtained -- involving the contributions of Bose-statistics and $S$-wave strong final-state interaction of two $K^0$ ($\bar{K}^0$) mesons and of
the $K^0$ and $\bar{K}^0$ mesons, as well as the additional one of transitions $K^+ K^- \rightarrow K^0 \bar{K}^0$, and depending
upon the relative fractions of generated pairs $K^0 K^0$, $\bar{K}^0 \bar{K}^0$, $K^0 \bar{K}^0$. It is shown that under the strangeness conservation the correlation functions of the pairs $K^0_S K^0_S$ and $K^0_L K^0_L$, produced in the same inclusive process, coincide, and the difference between the correlation functions of the pairs $K^0_S K^0_S$ and $K^0_S K^0_L$ is conditioned exclusively by the generation of pairs of non-identical neutral kaons $K^0 \bar{K}^0$.For comparison, analogous correlations for the pairs of neutral heavy mesons $D^0$, $B^0$ and $B_s^0$, produced in multiple inclusive
processes with charm (beauty) conservation, are also theoretically analyzed -- neglecting, just as for the case of $K^0$ mesons, the weak effects of $CP$ violation. These correlations have the quite similar character and they are described by quite similar expressions: in particular, just as for $K^0$ mesons, the correlation functions for the pairs of states with the same $CP$ parity ($R_{SS}=R_{LL}$) and with different $CP$ parity ($R_{SL}$) do not coincide, and the difference between them is conditioned exclusively by the production of pairs $D^{0}\bar{D}^{0}$, $B^{0}\bar{B}^{0}$ and $B_s^{0}\bar{B}_s^{0}$. However, contrary to the case of $K^0$ mesons, here the distinction of $CP$-even and $CP$-odd states (and, hence, the experimental observation of respective pair correlations) encounters difficulties -- due to the insignificant differences of their lifetimes and the relatively small probability of purely $CP$-even and $CP$-odd decay channels. Nevertheless, one may expect that this will become possible at future colliders.Speaker: Dr Valery Lyuboshitz (Joint Institute for Nuclear Research, Dubna ) -
53
Light neutral meson production in the era of precision physics at the LHC
The production of light neutral mesons in different collision systems is interesting for a variety of reasons: In AA collisions the measurements can provide important information on the energy loss of partons traversing the Quark-Gluon Plasma (QGP) which is formed in heavy-ion collisions at the LHC. Measured in pp collisions, neutral meson spectra serve as a reference for pA and AA collisions. Also, they allow us to test with high precision the predictions of perturbative QCD and other model calculations. In pA collisions, cold nuclear matter effects are studied. In addition, decays of $\pi^0$ and $\eta$ mesons are the dominant background for all direct photon measurements. Therefore, pushing the limits of the precision of neutral meson production is key to learning about the temperature and space-time evolution of the QGP.
In the ALICE experiment, which is dedicated to the study of the QGP, neutral mesons can be detected via their decay to two photons. The latter can be reconstructed using the two calorimeters EMCal and PHOS or via conversions in the detector material. Combining the excellent momentum resolution of the conversion photons down to very low transverse momenta ($p_{\text{T}}$) and the high reconstruction efficiency and triggering capability of calorimeters at high $p_{\text{T}}$, we are able to measure neutral mesons and direct photons over a wide transverse momentum range.
Combining state-of-the-art reconstruction techniques with the high statistics delivered by the LHC in Run 2 gives us the opportunity to enhance the precision of our measurements. In this talk, new results together with an overview of neutral meson production in pp, p--Pb and Pb--Pb collisions at LHC energies, as measured with the ALICE experiment will be presented.
Speaker: Mike Henry Petrus Sas (Nikhef National institute for subatomic physics (NL)) -
54
Rapidity distributions of pions in p+p and Pb+Pb collisions at CERN SPS energies
Our presentation will be largely based on our recent paper [1].
The centrality and energy dependence of rapidity distributions of pions in Pb+Pb reactions can be understood by imposing local energy-momentum conservation in the longitudinal “fire-streaks” of excited matter. With no tuning nor adjustment to the experimental data, the rapidity distribution of pions produced by the fire-streak which we obtained from Pb+Pb collisions reproduces the shape of the experimental pion rapidity distribution in p+p interactions, measured by the NA49 Collaboration at the same energy per nucleon. The observed difference in the absolute normalization of this distribution can be explained by the difference in the overall energy balance, induced by baryon stopping and strangeness enhancement phenomena occurring in heavy ion collisions. We estimate the latter effects using a collection of CERN SPS experimental data on π±, K±, net p, and n production in p+p and Pb+Pb reactions. We discuss the implications of the above findings for the understanding of particle production phenomena in both hadron-hadron and nucleus-nucleus collisions. In addition, we comment on the excellent accuracy in the determination of the energy balance at the CERN SPS, which can be used as an independent tool to test different models for hadronic or nuclear reactions.
[1] A. Rybicki, A. Szczurek, M. Kiełbowicz, A. Marcinek, V. Ozvenchuk, Ł. Rozpłochowski, Phys. Rev. C 99 (2019), 024908
Speaker: Antoni Marcinek (Polish Academy of Sciences (PL)) -
55
The quark-gluon plasma production from the QCD ground state in the Hamiltonian picture
A semi-classical Hamiltonian approach can be used to describe the quark-gluon plasma (QGP) production mechanism in heavy-ion collisions in real physical time based upon the existence of a homogeneous initial state being a non-trivial QCD ground-state. An effect ala parametric resonance leading to a decay of the homogeneous gluon condensate into inhomogeneous gluon plasma can be thought as a possible driver of QGP production in QCD as well as its hadronisation. I will elaborate on physical significance and the possible new signatures of this mechanism relevant for heavy-ion phenomenology.
Speaker: Roman Pasechnik (Lund university) -
56
Baryon production from small to large collision systems at ALICE
Studies of the production of light- and heavy-flavour baryons are of prominent importance to characterise the partonic phase created in ultrarelativistic heavy ion collisions and to investigate hadronisation mechanisms at the LHC. Studies performed in p--Pb and pp collisions have revealed unexpected features, qualitatively similar to what is observed in larger collision systems and, in the charm sector, not in line with the expectations from $e^{+}e^{-}$ and $e^{-}$p interactions. The ALICE experiment has exploited its excellent tracking and PID capabilities down to low transverse momentum to perform an extensive study of protons, hyperons and charmed baryons. A critical discussion of the most recent results on light (protons and hyperons) and heavy-flavour ($\Lambda_{\mathrm{c}}$ and $\Xi_{\mathrm{c}}$) baryon production will be presented, together with a comparison to phenomenological models. Emphasis will be given to the discussion of the impact of these studies on our understanding of hadronisation processes.
Speaker: Omar Vazquez Rueda (Lund University (SE))
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45
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Higgs Physics Campus Ledeganck - Aud. 5
Campus Ledeganck - Aud. 5
Ghent
Conveners: Martin Flechl (Austrian Academy of Sciences (AT)), Ramona Groeber (HU Berlin), Sinead Farrington (University of Warwick (GB))-
57
Measurements of Higgs boson properties in leptonic final states at CMS
This presentation will cover the most recent results on Higgs boson measurements using decays into leptons from the CMS experiment at the LHC.
Speaker: Olena Hlushchenko (RWTH Aachen) -
58
Measurements of Higgs boson production in decays to two tau leptons with the ATLAS detector
Testing the couplings of the Higgs boson to leptons is important to understand the origin of lepton masses. This talk presents measurements of Higgs boson production in Higgs boson decays to two tau leptons based on pp collision data collected at 13 TeV, as well as studies of the CP-nature of the HVV coupling in H→tautau decays.
Speaker: David Hohn (Albert Ludwigs Universitaet Freiburg (DE)) -
59
A universally enhanced light-quarks Yukawa couplings paradigm
We propose that natural TeV-scale new physics (NP) with $O(1)$ couplings to the standard model (SM) quarks may lead to a universal enhancement of the Yukawa couplings of all the light quarks, perhaps to a size comparable to that of the SM b-quark Yukawa coupling, i.e., $y_q \sim O(y^{SM}_b$) for $q=u,d,c,s$. I will discuss this scenario in an effective field theory (EFT) extension of the SM, and show that the potential EFT contribution to the light quarks Yukawa couplings is $y_q \sim O(f \frac{v^2}{Λ^2})$, where $\Lambda$ is the typical scale of the underlying heavy NP and $f$ depends on its properties and details. For example, with $\Lambda \sim 1.5$ TeV and natural NP couplings $f \sim O(1)$, one obtains $y_q \sim 0.025 \sim y^{SM}_b$. I will also discuss this enhanced light quarks Yukawa paradigm in extensions of the SM which contain TeV-scale vector-like quarks (VLQ) and match them to the EFT description. The flavor structure and the constraints on this scenario will also be explored as well as the resulting “smoking gun” signals that should be searched for at the LHC, e.g., multi-Higgs production $pp \to hh, hhh$ and single Higgs production in association with a high $p_T$ jet or photon and with a single top-quark, i.e., $pp \to hj, h \gamma$ and $pp \to ht$.
Speaker: Shaouly Bar-Shalom (Physics Department Technion, Israel) -
60
Light Yukawa couplings from double Higgs production
One of the puzzles of the SM is the large hierarchy between the Yukawa couplings of different flavours. Yukawa couplings of the first and the second generation are constrained only very weakly so far. However, one can obtain large deviations in the Yukawa couplings in several New Physics (NP) models, such as e.g new vector-like quarks, or new Higgs bosons that couple naturally to individual fermion families. In this talk, we investigate the potential bounds on the NP Higgs Yukawa couplings modification $ \kappa_f$ for light quarks from double-Higgs at the LHC. We start disscussing model-independent bounds and then we investigate specific models. We have looked at the Higgses' final states $ b \bar b \gamma \gamma $, and the relevant experimental cuts to reduce backgrounds and estimated the potential exclusion bounds for $ \kappa_f$ and $ \kappa_\lambda$ that can be achieved at the LHC for some models.
Speakers: Ms Lina Alasfar ( Humboldt Universität zu Berlin), Lina Alasfar (Max-Planck-Gesellschaft (DE)), Lina Alasfar (HU-Berlin) -
61
Measurements of Higgs boson production using decays to two b-quarks with the ATLAS detector
Testing the couplings of the Higgs boson to quarks is important to understand the origin of quark masses. The talk presents simplified template cross section measurements for Higgs boson production in association with a vector boson using decays to two b quarks using pp collision data collected at 13 TeV, along with an interpretation in an effective field theory framework. A search for vector-boson fusion production in the same Higgs decay channel will also be presented.
Speakers: Rute Costa Batalha Pedro (LIP Laboratorio de Instrumentacao e Fisica Experimental de Part), Rute Costa Batalha Pedro (LIP Laboratorio de Instrumentacao e Fisica Experimental de Part) -
62
Measurements of Higgs boson properties in hadronic final states at CMS
This presentation will cover the most recent results on Higgs boson measurements using decays into quarks from the CMS experiment at the LHC
Speaker: Leonardo Giannini (INFN Sezione di Pisa, Universita' e Scuola Normale Superiore, P) -
63
Muon identification and performance in the ATLAS experiment
Muon reconstruction and identification play a fundamental role in many analyses of central importance in the LHC run-2 Physics pro- gramme. The algorithms and the criteria used in ATLAS for the recon- struction and identification of muons with transverse momenta ranging from a few GeV to the TeV scale will be presented. Their performance is measured in data based on the decays of Z, Υ, and J/ψ to pairs of muons. Reconstruction and identification efficiencies are evaluated, as well as momentum scales and resolutions, and the results are used to derive Monte Carlo simulation corrections that in severasl cases reach the permit-level precision. Isolation selection requirements and their performance in presence of high pileup will also be presented.
Speaker: Peter Kluit (Nikhef National institute for subatomic physics (NL)) -
64
Discussion
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11:00 AM
Coffee break/Poster session
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65
Measurements of cross sections in Higgs boson decays to two W bosons with the ATLAS detector
The Higgs boson decay to two W bosons has the largest branching fraction and can be used to perform some of the most precise measurements of the Higgs boson production cross sections. Cross section measurements for Higgs boson production via gluon fusion, vector-boson fusion, and production in association with a vector boson based on pp collision data collected at 13 TeV will be presented.
Speaker: Pamela Ferrari (Nikhef National institute for subatomic physics (NL)) -
66
Measurements of Higgs boson properties in bosonic final states at CMS
Latest CMS results on Higgs boson property measurements in final states with photons, W and Z bosons will be presented.
Speaker: Filippo Errico (University of Florida (US)) -
67
Measurement of cross sections in Higgs boson decays to two photons with the ATLAS detector
Higgs boson decays to two photons can be selected with high efficiency, and the very good invariant mass resolution allow a robust subtraction of the backgrounds. This talk will present measurements of differential cross sections, as well as cross section measurements for the different Higgs boson production processes in the simplified template cross section framework using pp collision data collected at 13 TeV.
Speaker: Ioannis Nomidis (Centre National de la Recherche Scientifique (FR)) -
68
Measurement of cross sections in Higgs boson decays to four leptons with the ATLAS detector
Higgs boson decays to four leptons can be selected with a very high purity and are very well suited for measurements of Higgs boson properties, despite the small H→ZZ→4l branching ratio. This talk will present measurements of differential cross sections, as well as cross section measurements for the different Higgs boson production processes in the simplified template cross section framework using pp collision data collected at 13 TeV.
Speaker: Susumu Oda (Kyushu University (JP)) -
69
Disentangling Higgs and Electroweak Physics at Future Lepton Colliders
With Higgs couplings measurement prospects reaching the per-mille level at future lepton colliders, their interplay with the electroweak sector is expected to become relevant. We perform the first comprehensive Standard Model Effective Field Theory analysis covering jointly the Higgs and electroweak sectors. It allows us to investigate the impact of electroweak parameter uncertainties in Higgs couplings determination; to examine what electroweak measurements are needed to achieve the full potential of the precision Higgs physics program at future lepton colliders; and conversely to discuss the possible improvement to measurements electroweak parameters otherwise brought by Higgs measurements. For this we systematically compare reaches for circular and linear colliders with several proposed energies and polarization configurations.
Speaker: Dr Ayan Paul (INFN, Sezione di Roma) -
70
Higgs measurements at the FCC-ee
The future circular collider (FCC) study released a conceptual design report (CDR) in January 2019. The CDR highlights the potential for precision measurements and searches for new phenomena in the Higgs sector are among the most important goals in particle physics. Electron-positron collisions up to an energy of 365 GeV (FCC-ee) provide the ultimate precision with studies of Higgs boson couplings, mass, total width, and CP parameters, as well as searches for exotic and invisible decays.
Speaker: Biagio Di Micco (Universita' degli Studi di Roma Tre e Istituto Nazionale di Fisica Nucleare (INFN))
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57
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Neutrino Physics ICC - Baeckeland 3
ICC - Baeckeland 3
Ghent
Conveners: Federico Sanchez (Universite de Geneve (CH)), Francesco Terranova (Universita & INFN, Milano-Bicocca (IT)), Yasaman Farzan (Institute for research in fundamental sciences (IPM).)-
71
Probing Majorana neutrinos via double-$\beta$ decay with GERDA
A discovery of neutrinoless double beta ($0\nu\beta\beta$) decay would establish neutrinos as Majorana fermions and imply a violation of lepton number conservation. The GERDA collaboration searches for $0\nu\beta\beta$ decay by operating germanium detectors enriched in $^{76}$Ge in a cryostat filled with liquid argon. Instrumenting the cryostat with photosensors to enable read out of scintillation light from the argon, an unprecedented low background in the region of interest is reached, rendering the experiment effectively background free up to its design exposure of 100 kg yr. With the latest data release in mid 2018, GERDA was the first experiment to surpass a half-life sensitivity of $10^{26}$ yr for $0\nu\beta\beta$ decay. The experiment was recently upgraded, deploying a new type of germanium detector and improving the liquid argon instrumentation for the last stretch of its runtime until the end of 2019.
We will summarize the latest results and report on the performance since the upgrade.Speaker: Dr Roman Hiller (for the GERDA collaboration) -
72
Results from the CUORE experiment
The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay (0νββ) that has been able to reach the one-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a compact cylindrical structure of 19 towers. The construction of the experiment was completed in August 2016 with the installation of all towers in the cryostat. Following a cooldown, diagnostic, and optimization campaign, routine data-taking began in spring 2017. In this talk, we present the 0νββ results of CUORE from examining a total TeO2 exposure of 86.3 kg∙yr, characterized by an average energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts/(keV∙kg∙yr). In this physics run, CUORE placed the current best lower limit on the 130Te 0νββ half-life of > 1.3 × 10^25 yr (90% C.L.). We then discuss the additional improvements in the detector performance achieved in 2018, the latest evaluation of the CUORE background budget, and we finally present the most precise measurement of the 130Te 2νββ half-life to date.
Speaker: Antonio Branca (Universita e INFN (IT)) -
73
Final results of the CUPID-0 Phase I experiment
A convincing observation of neutrino-less double beta decay (0$\nu$DBD) relies on the possibility of operating high-energy resolution detectors in background-free conditions.
Scintillating cryogenic calorimeters are one of the most promising tools to fulfill the requirements for a next-generation experiment. Several steps have been taken to demonstrate the maturity of this technique, starting form the successful experience of CUPID-0.
The CUPID-0 experiment collected 10 kg*y of exposure, running 26 Zn$^{82}$Se crystals during two years of continuous detector operation. The complete rejection of the dominant alpha background was demonstrated, measuring the lowest counting rate in the region of interest for this technique. Furthermore, the most stringent limit on the Se-82 0$\nu$DBD was established.
In this contribution we present the final results of CUPID-0 Phase I, including a detailed model of the background and the measurement of the 2$\nu$DBD half-life.Speaker: Luca Maria Pattavina (INFN - National Institute for Nuclear Physics) -
74
NEXT: results from NEXT-White and roadmap toward the $\beta\beta0\nu$ search
The goal of the NEXT (Neutrino Experiment with a Xenon TPC) collaboration is the sensitive search of the neutrino-less double beta decay ($\beta\beta0\nu$) of $^{136}$Xe at the Laboratorio Subterraneo de Canfranc (LSC). The observation of such a lepton-number-violation process would prove the Majorana nature of neutrinos, providing also handles for an eventual measurement of the neutrino absolute mass. After a successful R\&D phase, a first large-scale prototype of a high-pressure gas-Xenon electroluminescent TPC is being operated at the LSC since 2016. NEXT-White is a 5-kg radiopure detector meant to understand the relevant backgrounds for the $\beta\beta0\nu$ search and to perform a measurement of the two neutrino mode of the double beta decay ($\beta\beta2\nu$). The operation of NEXT-White is setting the grounds for the construction of the NEXT-100 detector: a TPC holding 100 kg of $^{136}$Xe and reaching a sensitivity to the $\beta\beta0\nu$ half-life of 6$\times$10$^{25}$ y after 3 years of data taking. In this talk, the latest results from the NEXT-White detector will be presented. The calibration data have allowed to evaluate the performance of the NEXT technology in terms of the topology-based background rejection capabilities and the energy resolution. In particular, a world-leading resolution for a Xe TPC has been achieved ($<$1\% FWHM at 2.6 MeV). The radioactivity-induced backgrounds have also been measured using the data collected operating the detector with depleted xenon. These results validate the background model of the NEXT experiment, estimating less than 5$\times$10$^{-4}$ counts/keV/kg/year in the NEXT-100 detector. As NEXT-White is currently taking data with $^{136}$Xe, preliminary results on the measurement of the $\beta\beta2\nu$ half-life will be released in this talk. Finally, the status of NEXT-100 and future upgrades, like the Ba$^{++}$ tagging R\&D, will also be addressed.
Speaker: Pau Novella Garijo (Univ. of Valencia and CSIC (ES)) -
75
Comprehensive measurement of pp-chain solar neutrinos with Borexino
The sun is fueled by fusion reactions that convert hydrogen into helium. The vast majority of the resulting energy is produced through the proton-proton (pp) chain reaction. The byproducts of the various stages of the pp-chain are the so-called pp, pep, $^7\text{Be}$, $^8\text{B}$ and hep solar neutrinos. They are a unique tool to gain information about the internal structure of the sun, as well as an intense natural source of neutrinos that can be used to study neutrino properties. Another known set of fusion reactions is the carbon-nitrogen-oxygen (CNO) catalytic cycle which also produces neutrinos, but has not yet been observed.
The Borexino detector is a liquid scintillator detector located in Laboratori Nazionali del Gran Sasso in the mountains of central Italy. It is particularly suitable for measuring the solar neutrinos due to its unprecedented radio-purity and resolution at low energies. A comprehensive study of the pp-chain was presented in a recent Nature publication by the Borexino collaboration.
The measurement reports pp, $^7\text{Be}$ and pep neutrino fluxes with the highest precision ever achieved, $^8\text{B}$ with the lowest energy threshold, the first Borexino limit on hep neutrinos, as well as the best limit on CNO neutrinos. These results and their physics interpretations concerning, for example, the so-called solar metallicity puzzle and the electron-neutrino survival probability, as well as other highlights of the analysis, will be summarized in this talk. The talk is presented in the name of the Borexino collaboration.
Speaker: Mariia Redchuk (Forschungszentrum Jülich) -
76
Reactor antineutrino flux and spectrum measurement of Daya Bay Experiment
The Daya Bay Reactor Neutrino Experiment utilizes eight functionally identical detectors with large target volume to measure the antineutrino flux emitted from three pairs of powerful nuclear reactors at different baselines. The detectors are placed underground to provide enough shielding against cosmic rays induced backgrounds. The experiment can perform a high-statistics determination of the absolute reactor antineutrino flux and spectrum. It’s found that a deviation in the measured positron prompt energy spectrum with the comparison to model predictions. It’s observed a local discrepancy in the energy range of 4-6 MeV. The experiment gave the first measurement of individual spectra from 235U and 239Pu. This talk will report the latest measurements of antineutrino flux, spectral shape and evolution of these two quantities with nuclear fuel at Daya Bay.
Speaker: Mr Haoqi Lu (Institute of High Energy Physics, CAS, China) -
11:00 AM
Coffee break
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77
Latest Results from Double Chooz
On behalf of the Double Chooz (DC) collaboration, we’d like to propose a talk to report our latest results as of the latest publication (arXiv:1901.09445). We hereby report our latest measurement of Theta13. Special emphasis has been done for the validation of the systematics accuracy by the articulation of redundant measurements while DC exploits its unique simpler geometry to cancel almost completely the impact of questioned reactor flux model. Our Theta13 measurement continues to exhibit an inconclusive slightly higher value within an acceptable ≤2$\sigma$ effect of the latest Daya Bay and RENO results. Additionally, we also report the world most precise mean cross-section per fission ($\sigma_f$) in good agreement to all experiments so far, thus superseding Bugey4 results for the first time. DC also scrutinises the reactor model prediction discrepancies in terms of both rate and shape, including inter-experiment comparison and addressing the possible impact to the accuracy of Theta13 measurement. DC thus concludes that the reactor prediction model uncertainties are likely underestimated and we quantify using an empirical neutrino data driven approach. Also, an empirical prescription for a new reactor model systematics is presented as temporary empirical solution for as long as the prediction accuracy appears questioned and compromised.
Speaker: Philipp Soldin (RWTH Aachen University) -
78
JUNO potential for neutrino oscillation physics
JUNO is a Liquid Scintillator (LS) detector currently under construction in the south of China (Jiangmen city, Guangdong province). JUNO aims to detect the disappearance of reactor antineutrinos at an average baseline of 53 km, with the primary goal of determining the neutrino mass ordering and performing a sub-percent measurement of three of the neutrino oscillation parameters. This physics program is rooted in the detector’s capability to resolve, for the first time, the interference pattern between the solar and atmospheric oscillation modes, thanks to an unprecedented 3% energy resolution at 1 MeV.
The main purpose of this talk is to elaborate on JUNO expected sensitivity in terms of neutrino oscillation physics, showing the impact of JUNO prospective results within the global neutrino landscape. The talk will also address how the JUNO design is geared to achieve the target energy resolution by deploying more than 40000 PMTs of different size to detect at least 1200 photoelectrons per MeV of deposited energy. PMTs cover 78% of the detector surface, and are arranged in a spherical geometry to monitor 20 kton of ultra-pure Linear AlkylBenzene acting as the antineutrino target mass, which make JUNO the largest LS detector currently being built. The relation between the overall detector performance and physics sensitivity will also be briefly described.
Speaker: Marco Grassi (IN2P3 - CNRS) -
79
First Sub-Percent Exploration of PMNS Unitarity with LiquidO?
The last decade has witnessed a remarkable progress in the knowledge of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) neutrino mixing matrix upon the first observation and today’s precision (~3%) measurement of the θ13 mixing angle by the reactor experiments; i.e. Daya Bay (China), Double Chooz (France) and RENO (South Korea). However, only the JUNO experiment (China) will open, for the first time, the sub-percent precision era. The measurement of the (“solar") θ12 mixing angle is expected to reach <1% precision (today: ~4%) soon upon data taking in 2022. The ("atmospheric") θ23 mixing angle ultimate knowledge depends on the DUNE (USA) and Hyper-Kamiokande (Japan) next generation beam experiments. The ultimate precision is expected to reach the ~1% level, despite the so called “octant” ambiguity. These same experiments are expected to provide the most precise knowledge on CP-Violation. Hence, sub-percent precision across the entire PMNS matrix is reachable within the forthcoming 2030 decade, only if a sub-percent θ13 measurement was possible. If so, the unprecedented opportunity for competitive unitarity exploration will open, including sensitivity to hypothetical evidence for physics beyond 3 neutrino families — a critical building block of the Standard Model. However, none of the running or proposed experiments can yield such a precision on θ13. Ιn this talk, we shall describe the necessary experimental steps needed to yield “the missing experiment” to reach the world best knowledge on PMNS unitarity. The new hypothetical experiment relies on a novel methodology and a new detection technique, called LiquidO, in active R&D demonstration. Both will be described as well as full systematics uncertainty feasibility for the firs time. One of the most powerful sites is in Europe, which is to be highlighted too. A publication in preparation, this talk will be the first release.
Speaker: Dr Anatael Cabrera (LAL/LNCA - IN2P3/CNRS) -
80
Electromagnetic properties of neutrinos
Abstract:
A review of theory and phenomenology of neutrino electromagnetic properties is presented. A massive neutrino even in the easiest generalization of the Standard Model inevitably has nonzero electromagnetic characteristics, at least nonzero magnetic moment. Although its value, determined by the neutrino mass, is very small, in other BSM theories much larger values of magnetic moments are predicted.
A short introduction to the derivation of the general structure of the electromagnetic interactions of Dirac and Majorana neutrinos is presented.
A thorough account of electromagnetic interactions of massive neutrinos in the theoretical formulation of low-energy elastic neutrino-electron scattering is discussed on the basis of our recently published paper. The formalism of neutrino charge, magnetic, electric, and anapole form factors defined as matrices in the mass basis with account for three-neutrino mixing is presented.
Then we discuss experimental constraints on neutrino magnetic and electric dipole moments, electric millicharge, charge radius and anapole moments from the terrestrial laboratory experiments. A special credit is done to bounds on neutrino electromagnetic characteristics (including magnetic and electric dipole moments, millicharge and charge radius) obtained by the reactor (MUNU, TEXONO and GEMMA) and solar Super-Kamiokande and the recent Borexino and COHERENT experiments.
The effects of neutrino electromagnetic interactions in astrophysical and cosmological environments are also reviewed. The main manifestation of neutrino electromagnetic interactions, such as: 1) the radiative decay in vacuum, in matter and in a magnetic field, 2) the Cherenkov radiation, 3) the plasmon decay, 4) spin light in matter, 5) spin and spin-flavour precession, 6) neutrino pair production in a strong magnetic field, and the related processes along with their astrophysical phenomenology are also considered.
The best world experimental bounds on neutrino electromagnetic properties are confronted with the predictions of theories beyond the Standard Model. It is shown that studies of neutrino electromagnetic properties provide a powerful tool to probe physics beyond the Standard Model.
References:
[1] C. Guinti and A. Studenikin, “Neutrino electromagnetic interactions: A window to new physics”, Rev. Mod. Phys. 87 (2015) 531-591.
[2] A. Studenikin, “Neutrino electromagnetic properties: A window to new physics – II” , PoS (EPS-HEP2017) 137, arXiv:1801.08887.
[3] A. Popov, A. Studenikin, “Neutrino oscillations and exact eigenstates in magnetic field”,
accepted to Eur. Phys. J. C (2019), arXiv:1803.05755 v2, January 13, 2019.[4] A. Popov, A. Pustoshny, A. Studenikin, “Neutrino motion and spin oscillations in magnetic field and matter currents”, PoS EPS-HEP2017 (2018) 643, arXiv:1801.08911.
[5] K. Kouzakov, A. Studenikin, “Electromagnetic properties of massive neutrinos in low-energy elastic neutrino-electron scattering”, Phys. Rev. D 95 (2017) 055013.
[6] P. Kurashvili, K. Kouzakov, L. Chotorlishvili, A. Studenikin, “Spin-flavor oscillations of ultrahigh-energy cosmic neutrinos in interstellar space: The role of neutrino magnetic moments”, Phys. Rev. D 96 (2017) 103017.
[7] A. Grigoriev, A. Lokhov, A. Studenikin, A. Ternov, “Spin light of neutrino in astrophysical environments”, JCAP 1711 (2017) no.11, 024.
[8] P. Pustoshny, A. Studenikin, “Neutrino spin and spin-flavour oscillations in transversal matter currents with standard and non-standard interactions”, Phys. Rev. D 98 (2018) no.11, 113009.
[9] M. Cadeddu, C. Giunti, K. Kouzakov, Y.F. Li, A. Studenikin, Y.Y. Zhang, “Neutrino charge radii from COHERENT elastic neutrino-nucleus scattering”,
Phys. Rev. D 98 (2018) no.11, 113010.[10] D. Papoulias, T. Kosmas, “COHERENT constraints to conventional and exotic neutrino physics”, Phys. Rev. D 97 (2018) 033003.
[11] M. Agostini et al (Borexino coll.), “Limiting neutrino magnetic moments with Borexino Phase-II solar neutrino data”, Phys. Rev. D 96 (2017) 091103.
[12] ] S. Arceo-Díaz, K.-P. Schröder, K. Zuber and D. Jack, “Constraint on the magnetic dipole moment of neutrinos by the tip-RGB luminosity in ω-Centauri”,
Astropart. Phys. 70 (2015) 1.[13] A. Studenikin, “New bounds on neutrino electric millicharge from limits on neutrino magnetic moment”, Europhys. Lett. 107 (2014) 21001.
[14] A. Studenikin, I. Tokarev, “Millicharged neutrino with anomalous magnetic moment in rotating magnetized matter”, Nucl. Phys. B 884 (2014) 396-407.
[15] K. Kouzakov, A. Studenikin, “Theory of neutrino-atom collisions: The history, present status and BSM physics”, Adv. High Energy Phys. 2014 (2014) 569409.
[16] A. Beda, V. Brudanin, V. Egorov et al., “The results of search for the neutrino magnetic
moment in GEMMA experiment”, Adv. High Energy Phys. 2012 (2012) 350150.[17] N. Viaux, M. Catelan, P. B. Stetson, G. G. Raffelt et al., “Particle-physics constraints from the globular cluster M5: neutrino dipole moments”, Astron. & Astrophys. 558 (2013) A12.
[18] G. Raffelt, “New bound on neutrino dipole moments from globular-cluster stars“, Phys. Rev. Lett. 64 (1990) 2856.
Speaker: Prof. Alexander Studenikin (M.V. Lomonosov Moscow State University & JINR (RU))
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71
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Searches for New Physics Campus Ledeganck - Aud. 1
Campus Ledeganck - Aud. 1
Ghent
Conveners: Christina Jane Potter (University of Cambridge (GB)), David Marzocca (INFN Trieste), Robert Schoefbeck (Austrian Academy of Sciences (AT))-
81
Searches for supersymmetry via strong production in all-hadronic final states at CMS
We present searches for new physics in events with one or more jets accompanied by large missing transverse momenta produced in proton-proton collision data recorded by the CMS experiment during the LHC Run2 operations (2016-18). Compressed chargino-neutralinos appearing in gluino cascades are studied using short tracks. The results are interpreted in the context of several simplified models of pair-production of gluinos and squarks.
Speaker: Laurent Thomas (Universite Libre de Bruxelles (BE)) -
82
Searches for promptly decaying squarks and gluinos with ATLAS
Despite the absence of experimental evidence, weak-scale supersymmetry remains one of the best motivated and studied Standard Model extensions. This talk summarizes recent ATLAS results on inclusive searches for supersymmetric squarks of the first two generations and gluinos. It covers both R-parity conserving models that predict dark matter candidates and R-parity violating models that typically lead to high-multiplicity final states without large missing transverse momentum. The searches target final states including jets, leptons, photons, and missing transverse momentum.
Speaker: Nikola Makovec (LAL-Orsay (FR)) -
83
Pair production of electroweak superpartners at the LHC in NLO+NLL with resummation-improved parton densities
We make use of recently released parton density functions (PDFs) with threshold-resummation improvement to consistently calculate theoretical predictions for neutralino-chargino and slepton pair production at next-to-leading order and next-to-leading logarithmic accuracy. The updated cross sections have been computed for experimentally relevant higgsino/gaugino and slepton search channels at the ongoing Run II of the LHC. A factorisation method is applied to exploit the smaller PDF uncertainty of the global PDF sets and to avoid complications arising in the refitting of threshold-resummation improved PDF replicas in Mellin space. The reduction of the scale uncertainty due to the resummation is, however, explicitly taken into account. As expected, the resummation contributions in the PDF fits partially compensate the cross section enhancements induced by those in the partonic matrix elements.
Speaker: Michael Klasen -
84
Search for electroweak production of supersymmetry at CMS
We present searches for pair production of supersymmetric partner of tau-leptons, and of partners of electroweak gauge bosons in events with at least one tau-lepton and missing transverse momenta produced in proton-proton collision data recorded by the CMS experiment during the LHC Run2 operations. The results are interpreted in terms of simplified models of supersymmetry production and decay of these of these particles.
Speaker: Valentina Dutta (Univ. of California Santa Barbara (US)) -
85
Searches for charginos, neutralinos and sleptons with the ATLAS detector
Many supersymmetry models feature gauginos and sleptons with masses less than a few hundred GeV. These can give rise to direct pair production rates at the LHC that can be observed in the data sample recorded by the ATLAS detector. The talk presents recent ATLAS results from searches for pair produced charginos and neutralinos or sleptons in final states with leptons (including hadronic taus) and missing transverse momentum.
Speaker: Sarah Louise Williams (University of Cambridge (GB)) -
86
Searches for electroweak production of supersymmetric particles involving the Higgs boson and the higgsino with ATLAS
Fine-tuning arguments suggest the mass of the supersymmetric partner of the Higgs boson, the higgsino, is not too far from the weak scale. The search for higgsinos represents an experimental challenge due to the near mass-degeneracy resulting in soft decay products, and the low production cross section. This talk presents recent ATLAS results of analyses explicitly targeting the higgsino with a variety of experimental techniques, as well as searches for electroweak production of supersymmetric particles in final states involving the Higgs boson.
Speaker: Francisco Alonso (National University of La Plata (AR)) -
87
Searches for direct production of third generation squarks at CMS
We present searches for third generation of supersymmetric top and bottom quarks based on proton-proton collision data recorded by the CMS experiment during the LHC Run2 operations (2016-18). The searches are performed in zero, single lepton (including taus) and dilepton final states, and the results are interpreted in the context of several decay modes of stop quarks.
Speaker: Caroline Collard (Centre National de la Recherche Scientifique (FR)) -
88
Searches for direct pair production of third generation squarks with the ATLAS detector
Naturalness arguments for weak-scale supersymmetry favour supersymmetric partners of the third generation quarks with masses light enough to be produced at the LHC. The ATLAS experiment has a variety of analyses devoted to stop direct production exploiting advanced analysis techniques. This talk presents recent results of searches for stops and sbottoms, including models with long decay chains involving Higgs and/or Z bosons, and their interpretation in associated-production DM models.
Speaker: Keisuke Yoshihara (University of Pennsylvania (US)) -
11:00 AM
Coffee break
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89
LHC constraints on the minimal Dirac gaugino model.
Most SUSY searches at the LHC are optimised for the MSSM, where gauginos are Majorana particles. By introducing Dirac gauginos, we obtain an enriched phenomenology, from which considerable differences in the LHC signatures and limits are expected as compared to the MSSM. Concretely, in the minimal Dirac gaugino model (MDGSSM) we have six neutralino and three chargino states. Moreover, production cross sections are enhanced for gluinos, while for squarks they are suppressed. In this talk, we explore the consequences for the current LHC limits on gluinos and squarks. This is based on the recent paper arXiv:1812.09293. We also comment on ongoing work regarding electroweak-ino phenomenology in the MDGSSM.
Speaker: Humberto Reyes-González (LPSC Grenoble) -
90
Search for RPV and stealth top squarks at CMS
We present searches for new physics scenarios like R-parity violating supersymmetry or compressed mass spectra which predict low missing transverse momenta, many jets and top quarks. The searches are based on proton-proton collision data recorded by the CMS experiment during the LHC Run2 operations.
Speaker: Dr Kin Ho Lo (University of Florida (US)) -
91
New Physics interpretations with GAMBIT
I will present recent results from the Global and Modular
Beyond-the-Standard-Model Inference Tool (GAMBIT)
collaboration. Global fits with GAMBIT have been carried out on many
models including supersymmetric models, scalar singlet dark matter,
fermionic and vector Higgs portal dark matter and axions. In this
talk I will focus on our most recent study interpreting collider
constraints on electroweakinos (arXiv:1809.02097). First we show that
when the neutralinos and charginos are the only light states of the
MSSM, there are scenarios which evade LHC constraints for any mass of
the lightest neutralino and the lightest chargino, i.e. the profile
likelihood shows no constraint in this plane when one only considers
the possibility of excluding new physics. Intriguingly, in addition
we also find that excesses in the data can lead to closed contours,
indicating a preference for light neutralinos and charginos over the
standard model. We find the excess has a local significance of 3.3
sigma when combining ATLAS and CMS 13 TeV searches, which drops to
2.9 sigma when including 8 TeV searches as wellSpeaker: Peter Athron -
92
The ILC as a natural SUSY discovery machine and precision microscope: From light higgsinos to tests of unification
The requirement of electroweak naturalness in simple supersymmetric models motivates the existence of a cluster of four light higgsinos with mass 100-300 GeV, the lighter the better. While such light compressed spectra may be challenging to observe at LHC, future e+e- colliders with sqrt(s) > 2m(higgsino) would serve as both a SUSY discovery machine and a precision microscope.
We study higgsino pair production signatures at the ILC based on full, Geant4-based simulation of the ILD detector concept. We examine several benchmark scenarios that may or may not be accessible to HL-LHC searches, with mass di?fferences between the higgsino states between 20 and 4 GeV. Assuming
sqrt(s)=? 500 GeV and 1000 fb^-1 of integrated luminosity, the individual higgsino masses can be measured to 1-2% precision in case of the larger mass diff?erences, and still at the level of 5% for the smallest mass diff?erence case. The higgsino mass splittings are sensitive to the electroweak gaugino masses and can allow extraction of gaugino masses to ? 3 - 20% (depending on the model).
Extrapolation of gaugino masses via renormalization group running can test the hypothesis of gaugino mass uni?cation. We also examine a case with natural generalized mirage mediation where the uni?cation of gaugino masses at an intermediate scale apparently gives rise to a natural SUSY spectrum somewhat beyond the reach of HL-LHC.Speaker: Swathi Sasikumar (DESY)
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81
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Top and Electroweak Physics ICC - Baeckeland 2
ICC - Baeckeland 2
Ghent
Conveners: Cen Zhang (Institute of High Energy Physics, Chinese Academy Sciences), Maria Jose Costa (IFIC Valencia (ES)), Pedro Vieira De Castro Ferreira Da Silva (CERN)-
93
Top-quark electroweak interactions at high energy
Modified interactions in the electroweak sector may lead to scattering amplitudes that grow with energy compared to their Standard Model (SM) counterparts. We present a detailed study of all 2→2 scattering amplitudes involving at least one top quark and a pair of EW bosons. We analyse the high energy behaviour of the amplitudes using the Standard Model Effective Field Theory (SMEFT) to parametrise the departures from the SM. We discuss the origin of the energy growth that arise from effective contact interactions by appealing to the Goldstone equivalence theorem and find that the amplitudes obey expected patterns of (non-)interference. The results are connected to unitary-violating behaviour in the framework of anomalous SM interactions. Therein, we identify the appearance of additional growth due to the violation of SU(2) gauge symmetry that leads to substantial differences between the SMEFT and the anomalous couplings approaches. We also discuss the embeddings of the scattering amplitudes into physical collider processes, presenting the parametric SMEFT sensitivity to relevant top quark operators and paying special attention to the extent to which the high energy behaviour of the 2→2 amplitude is retained in the actual processes accessible at colliders. The effective W approximation is exploited to gain analytical insight into the embeddings of the 2→2 helicity amplitudes. Finally, we provide a compendium of processes detailing numerous directions in which the SMEFT parameter space can be accessed through high energy top quark processes in current and future colliders.
Speaker: Mr Luca Mantani (UCLouvain) -
94
Comparison of direct and indirect constraints on anomalous tWb couplings
We analyze constraints on anomalous tWb couplings that parameterize the possible contribution of New Physics to the weak tWb vertex. We take into account indirect constraints obtained from B-physics ($B\to X_s \gamma$, $B\to X_s l^+l^-$, $B$-$\bar B$ oscillations) and direct constraints from the t-channel single top quark production. In two-dimensional scenarios when different pairs of the anomalous couplings can vary whereas others are set to their SM values, the indirect and direct constraints are shown to nicely agree with each other. Combining both types of constraints narrows down the allowed ranges of the anomalous couplings.
Speaker: Anastasiia Kozachuk (Lomonosov Moscow State University) -
95
The Matrix Element Method as a tool for precision and accuracy
The Matrix Element Method is a promising multi-variate analysis method which offers an optimal approach to compare theory and experiment. However, until recently its usage has been limited by the fact that only leading-order predictions could be employed. This rather crude approximation of the underlying probability distribution can introduce a significant bias into the analysis which requires a major calibration for the method to be accurate. Moreover, the estimation of the theoretical uncertainties by scale variation in the Born-level calculation may yield unreliable results. We present the extension of the Matrix Element Method to the next-to-leading order in QCD readily applicable to LHC data. The accuracy gain is illustrated by determining the top-quark mass from single top-quark events generated with POWHEG+Pythia. Additionally, the method's potential for BSM parameter determination is demonstrated by extracting a CP-violating Top-Yukawa coupling from events of single top-quarks in association with a Higgs boson.
Speaker: Till Martini (HU Berlin) -
96
Production of $W^+ W^-$ and $t \bar t$ pairs via photon-photon processes in proton-proton scattering and corresponding gap survival factor
Photon-induced processes in proton-proton interactions have become recently very topical. The large energy at the LHC, when combined with relatively large luminosity at run II, allows starting the exploration of such processes.
We discuss the production of $W^+ W^-$ pairs and $t \bar t$ quark-antiquark pairs in proton-proton collisions induced by two-photon fusion including, for a first time, transverse momenta of incoming photons. The unintegrated inelastic fluxes (related to proton dissociation) of photons are calculated based on modern parametrizations of deep inelastic structure functions in a broad range of $x$ and $Q^2$.
We focus on processes with single and double proton dissociation. Highly excited remnant systems hadronize producing particles that can be vetoed in the calorimeter. We calculate associated effective gap survival factors. The gap survival factors depend on the process, mass of the remnant system and collision energy. The rapidity gap survival factor due to remnant fragmentation for double
dissociative (DD) collisions is smaller than that for single dissociative (SD) process. We observe approximate factorisation: $S_{R,DD} \approx S_{R,SD}^2$ when imposing rapidity veto. For the $W^+W^-$ final state, the remnant fragmentation leads to a taming of the cross section when the rapidity gap requirement is imposed. Also for $t \bar t$ quark-antiquark pairs, such a condition reverses the hierarchy observed for the case when such condition is taken into account.Our results imply that for the production of such heavy objects as $t$ quark and $\bar t$ antiquark the virtuality of the photons attached to the dissociative system are very large ($Q^2 <$ 10$^{4}$ GeV$^2$). A similar effect was observed for the $W^+ W^-$ system.
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M. Luszczak, L. Forthomme, W. Schafer, A. Szczurek,
JHEP 1902 (2019) 100. -
L. Forthomme, M. Luszczak, W. Schafer, A. Szczurek,
Phys.Lett. B789 (2019) 300-307. -
M. Luszczak, W. Schafer, A. Szczurek,
JHEP 1805 (2018) 064. -
M. Luszczak, W. Schafer and A. Szczurek,
Phys. Rev. D93 (2016) 7, 074018. -
M. Luszczak, A. Szczurek, Ch. Royon,
JHEP 1502 (2015) 098.
Speakers: Marta Luszczak (University of Rzeszow), Antoni Szczurek (Institute of Nuclear Physics) -
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97
Recent top quark properties in CMS
(Includes single top) Measurements of top quark properties using data collected by the CMS experiment are presented. Among them, latest results on top mass, ttbar spin correlations, Yukawa coupling, charge asymmetries, and others will be discussed.
Speaker: Agostino De Iorio (Universita e sezione INFN di Napoli (IT)) -
98
FCNC and EFT interpretations in top quark events in CMS
Top quark production can probe physics beyond the SM in different ways. This talks reviews the current limits on FCNC searches in the top sector, and EFT interpretations in many top quark production modes.
Speaker: Kirill Skovpen (Vrije Universiteit Brussel (BE)) -
99
Top quark pair property measurements using the ATLAS detector at the LHC
Precise measurements of the properties of the top quark test the Standard Model (SM) and can be used to constrain new physics models. The top-quark is predicted in the SM to decayalmost exclusively into a W boson and a b-quark. We present a wide range of searches for non-SM top quark decays using the 13 TeV ATLAS datasets, including t->q H and t->q Z. In addition, measurements of the spin correlation and colour flow in ttbar production are also presented.
Speaker: James William Howarth (University of Manchester (GB)) -
100
Measurements of the top quark mass using the ATLAS detector at the LHC
The latest measurements of the top quark mass using the ATLAS experiment are presented. A measurement based on a multi-dimensional template fit that can constrain the uncertainties on the energy measurements of jets is presented and combined with measurements using dilepton and all-hadronic events. In addition, an analysis of the top quark mass using leptonic kinematic variables is discussed. The measurement uses a novel technique to measure the top quark mass with minimal dependence on hadronic jets. The measurements that use precision theoretical QCD calculations for both inclusive ttbar production and ttbar production with an additional jet to extract the top quark mass in the pole-mass scheme are also presented.
Speaker: Andrea Helen Knue (Albert-Ludwigs-Universitaet Freiburg (DE)) -
11:00 AM
Coffee break
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101
Three-loop soft anomalous dimensions for top-quark production
I present results through three loops for soft anomalous dimensions that control soft-gluon emission in processes involving the top quark. In particular I present results for channels in single-top production and top-pair production as well as for processes with new physics, including tZ, tZ', t gamma, and tH- production. These calculations are ingredients to resummations at N3LL accuracy and to derivations of N3LO soft-gluon corrections.
Speaker: Nikolaos Kidonakis (Kennesaw State University) -
102
Top-quark pair production at NNLO
The study of top-quark production and decay is central in the LHC physics programme, allowing to test the Standard Model and offering a window on possible new physics. Precise theoretical predictions are crucial for these analysis.
In this talk, we report on a new calculation of the next-to-next-to-leading order QCD radiative corrections to the inclusive production of top-quark pairs at hadron colliders. The calculation is performed by using the $q_T$-subtraction formalism to handle and cancel infrared singular contributions at intermediate stages of the computation, and represents its first complete application to the hadroproduction of a colorful high-mass system at next-to-next-to-leading order. The numerical results are also presented and discussed.Speaker: Javier Mazzitelli -
103
Recent ttbar and single top inclusive cross sections results in CMS
Latest results on inclusive top quark pair and single top quark production cross sections are presented using proton-proton collision data collected by CMS. The single top quark analyses investigate separately the production of top quarks via t-channel exchange, via associated production with a W boson (tW), and via the s-channel.
Speaker: Juan Gonzalez (Universidad de Oviedo (ES)) -
104
Top quark pair and single top differential cross sections in CMS
Differential measurements of top quark pair and single top quark production cross sections are presented using data collected by CMS. The cross sections are measured as a function of various kinematic observables of the top quarks and the jets and leptons of the event final state. The results are confronted with precise theory calculations. Multidifferential tt cross sections are presented and used to constrain simultaneously the top quark pole mass, alphaS, and PDFs.
Speaker: Otto Heinz Hindrichs (University of Rochester (US)) -
105
Top quark pair-production cross-section measurements with the ATLAS detector
Measurements of the inclusive and differential top-quark pair production cross sections in proton-proton collisions at 13 TeV with the ATLAS detector at the Large Hadron Collider are presented. The inclusive measurements reach high precision and are compared to the best available theoretical calculations. Differential measurements of the kinematic properties of the top quark production are also discussed. These measurements, including results using boosted top quarks, probe our understanding of top-quark pair production in the TeV regime. The results, unfolded to particle and parton level, are compared to predictions of Monte Carlo generators implementing NLO matrix elements matched with parton showers and NNLO QCD theory calculations.
Speaker: Michele Faucci Giannelli (University of Edinburgh) -
106
Single-top-quark production cross section using the ATLAS detector at the LHC
Measurements of single-top-quark production in proton-proton collisions are presented based on the 8 TeV and 13 TeV ATLAS datasets. The recent combination of the ATLAS and CMS Run 1 single-top-quark measurements is discussed. This combination leads to the most precise direct measurement of the CKM-matrix element Vtb. An interesting quantum effect is the interference of tW and top-quark-pair production which is studied in a dedicated analysis. Differential cross-sections of the tW process have also been measured. The large Run 2 data set gives also access to rare single-top-quark processes, such as tZ production. The latest results on this production mode will be reviewed.
Speaker: Muhammad Alhroob (University of Oklahoma (US))
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93
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1:00 PM
Lunch Break
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Astroparticle Physics and Gravitational Waves Campus Ledeganck - Aud. 3
Campus Ledeganck - Aud. 3
Ghent
Conveners: Elisa Resconi (Technical University Munich), Francesca Calore (LAPTh, CNRS), Tania Regimbau-
107
The Latest Results from the Alpha Magnetic Spectrometer on the ISS
Precision measurements by AMS of the fluxes of cosmic ray positrons, electrons, antiprotons, protons and light nuclei as well as their ratios reveal several unexpected and intriguing features. The presented measurements extend the energy range of the previous observations with much increased precision. The new results show that the positron flux rises from ∼10 GeV above the rate expected from cosmic ray collisions with interstellar gas and at energies ~300 GeV exhibits behavior consistent with a new source of high energy positrons. Surprisingly, at similar rigidities the spectra of cosmic ray nuclei show progressive hardening over the interval of few hundred GV. Most importantly, AMS continues studies of complex antimatter candidates with stringent detector verification and collection of additional data.
Speaker: Andrei Kounine (Massachusetts Inst. of Technology (US)) -
108
Properties of Primary and Secondary Cosmic Ray Nuclei Measured with the Alpha Magnetic Spectrometer on the ISS
We present precision measurements of primary and secondary cosmic rays by Alpha Magnetic Spectrometer in the rigidity range up to several TV. These measurements are based on high statistics nuclei samples collected by AMS during the first 7 years of operation aboard the International Space Station. Surprisingly, at ~200 GV all the measured nuclei spectra experience progressive hardening over the rigidity interval of few hundred GV. This hardening is more pronounced for the secondary nuclei such as lithium, beryllium, and boron than for the primary nuclei as helium, carbon and oxygen. The properties of cosmic ray nuclei isotopes will also be discussed.
Speaker: Laurent Yves Marie Derome (LPSC Laboratoire de Physique Subatomique et de Cosmologie (LPSC)) -
109
Anisotropy of Cosmic Ray Fluxes Measured with the Alpha Magnetic Spectrometer on the ISS
Analysis of anisotropy of the arrival directions of galactic protons, electrons and positrons has been performed with the Alpha Magnetic Spectrometer on the International Space Station. These results allow to differentiate between point-like and diffuse sources of cosmic rays for the explanation of the observed excess of high energy positrons. The AMS results on the dipole anisotropy are presented along with the discussion of implications of these measurements.
Speaker: Jorge Casaus (Centro de Investigaciones Energéti cas Medioambientales y Tecno) -
4:00 PM
Coffee break
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110
The DAMPE experiment: performances and first results
The DAMPE (DArk Matter Particle Explorer) experiment, in orbit since December 17th 2015, is a space mission whose main purpose is the detection of cosmic electrons and photons up to energies of 10 TeV, in order to identify possible evidence of Dark Matter in their spectra. Furthermore it aims to measure the fluxes and the elemental composition of the galactic cosmic rays nuclei up to 100 TeV, in order to get a better understanding of the galactic sources, acceleration mechanisms and propagation processes in the Galaxy. The DAMPE detector consists of: a double layer of Plastic Scintillator Detector; a Silicon-tungsten Tracker-converter; an electromagnetic calorimeter (composed by BGO crystals) and a Neutron Detector. We intend to present and discuss the performances of the detector and the main scientific results obtained after three years of data taking.
Speaker: Mr Antonio De Benedittis (Università del Salento and INFN Lecce) -
111
An overview of CALET observations after three years on the International Space Station
The CALorimetric Electron Telescope CALET is a space instrument designed to carry out precision measurements of high energy cosmic-rays on the JEM-EF external platform of the ISS where it has been collecting science data continuously since mid October 2015.
Equipped with a thick (30 X0 , 1.3 λI ) calorimeter with an imaging pre-shower and with two independent subsystems to identify the charge of the incident particle, CALET has the depth, tracking capability, electron/proton discrimination and energy resolution to study hadrons, electrons and gamma rays.
An overview of CALET observations is presented, based on the data taken during the first three years.
It includes a direct measurement of the electron+positron energy spectrum from 11 GeV to 4.8 TeV in good agreement with AMS-02 data in the region below 1~TeV and suggesting a flux suppression above 1 TeV. In the energy region below ∼300~GeV, CALET's spectral index is consistent with AMS-02, Fermi-LAT and DAMPE, while from 300~GeV to 600~GeV the spectrum is significantly softer than the spectra from the latter two experiments.
The proton spectrum has been measured from 50 GeV to 10 TeV covering, for the first time with a single space-borne instrument, the whole energy interval previously investigated in separate sub-ranges by magnetic spectrometers and calorimetric instruments. The observed spectrum is consistent with AMS-02 but it extends by nearly one order of magnitude higher in energy, showing a smooth transition of the power-law spectral index from -2.81 +- 0.03 (50–500 GeV) to -2.56 +- 0.04 (1–10 TeV), thereby providing evidence of a deviation from a single power law by more than 3 sigma.
In addition to its primary goal of identifying nearby sources of high-energy electrons and possible signatures of dark matter in the electron spectrum, CALET is carrying out extensive measurements of the energy spectra, relative abundances and secondary-to-primary ratios of elements from proton to iron and above (up to Z=40) studying the details of galactic particle propagation and acceleration.
Preliminary spectra of cosmic-ray nuclei are presented, together with gamma-ray observations and searches of an e.m. counterpart of LIGO/Virgo GW events.Speaker: Prof. Pier Simone Marrocchesi (Univ. of Siena and INFN Pisa) -
112
The High Energy cosmic-Radiation Detection (HERD): a probe for high-energy cosmic rays’ physics and multimessenger astronomy
The High Energy cosmic-Radiation Detection (HERD) facility has been proposed as one of several space astronomy payloads onboard the future China’s Space Station (CSS) aimed to detect charged cosmic-rays and gamma-rays from few GeV to PeV energies.
The main science objectives of HERD are searching dark matter particle, the study of cosmic ray chemical composition up to the knee and high energy gamma-ray observations.
HERD consists of a very thick (3 lambda, 55 X0) cubic calorimeter made of small LYSO cubic crystals allowing 3D reconstruction, a tracker consisting of silicon microstrip detectors and thin converter foils for gamma conversion and plastic scintillator plates for veto and charge measurements. HERD will extend high precision and high statistics measurement of cosmic ray spectra up to 1 PeV. It will also observe the gamma-ray sky from a few GeV up to 1 TeV contributing to multi-messenger astronomy together with ground-based high energy gamma-ray telescope (CTA, HAWC) and neutrino and gravitational waves detectors.Speaker: Fabio Gargano (Universita e INFN, Bari (IT)) -
113
LHCb inputs to astroparticle physics
The LHCb experiment has the unique possibility, among the LHC experiments, to be operated in fixed-target mode using its internal gas target. The energy scale achievable at the LHC and the excellent detector capabilities for vertexing, tracking and particle identification allow a wealth of novel measurements of great interest for cosmic ray physics. In particular, using a helium target, the first measurement of antiproton production in proton-helium collisions was achieved using a 6.5 TeV proton beam, for antiproton energies in the range 12-110 GeV. The results are particularly relevant to the interpretation of the recent precise measurements of the antiproton flux in cosmic rays.
Speaker: Giacomo Graziani (INFN, Sezione di Firenze (IT)) -
114
Latest results of the LHCf experiment
The main aim of the LHC forward (LHCf) experiment is to precisely measure very forward particle production in high energy p-p and p-ion collisions. These experimental results are necessary for the tuning of hadronic interaction models used to simulate the Extensive Air Showers (EAS) generated from the interaction of Ultra High Energy Cosmic Rays (UHECR) with the Earth atmosphere. The two main analysis targets of the experiment are: $\pi^{0}$/photons, important to understand the evolution of the electromagnetic component of EAS; neutrons, important to derive the process inelasticity and to understand the muon component of EAS. During LHC Run II, the experiment acquired data relative to p-p collisions at $\sqrt{s}$ = 13 TeV, which allows us to study particle production in $\eta$ > 8.4 at the highest energy ever available. In this talk, we would like to present the analysis results relative to forward photons and neutrons produced in p-p collisions at $\sqrt{s}$ = 13 TeV, two recently published measurements that highlighted a significant model-data discrepancy. We will also show the first results relative to the ATLAS-LHCf joint analysis, which is a very powerful tool to study forward particle production distinguishing between different production mechanisms, like diffractive and non-diffractive processes. Finally, we will discuss about the analysis and operation prospects of the LHCf experiment in the incoming years.
Speaker: Eugenio Berti (Universita e INFN, Firenze (IT)) -
115
Upper Limits on Very-High-Energy Gamma-ray Emission from Core-Collapse Supernovae Observed with H.E.S.S.
The sources of cosmic-rays beyond the knee of the cosmic-ray spectrum 10$^{15}$eV (= 1 PeV) are not firmly discovered yet. Supernovae remnants (SNR) have been proven to be able to accelerate cosmic-rays up to ∼ 10$^{14}$eV, but not beyond. Supernovae (SNe), the precursor phase of SNRs, are good candidates for PeV acceleration as some recent theoretical studies indicate that particles with PeV energies and beyond shall be produced as the SN shock propagates in a very dense environment and this may result in measurable gamma-ray emission.
In that context, we searched for gamma-ray emission from ten supernovae observed with the High Energy Stereoscopic System (H.E.S.S.) within a year of the supernova event. No significant gamma-ray emission was detected for any of the objects, and upper limits on the > 1 TeV gamma-ray flux of the order of ~10$^{-13}$cm$^{-2}$s$^{-1}$ are derived. These values are used to place model-dependent constraints on the mass-loss rates of the progenitor stars, implying upper limits between 2 x 10$^{-5}$ and 2 x 10$^{-3}$ M⊙.yr$^{-1}$ , under reasonable assumptions on the particle acceleration parameters. Furthermore, the prospect of a future > 1 TeV gamma-ray detection of a young supernova is investigated and found to be a distinct possibility with H.E.S.S. or the Cherenkov Telescope Array (CTA).Speaker: Rachel Simoni (Rachel)
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107
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Dark Matter Campus Ledeganck - Aud. 2
Campus Ledeganck - Aud. 2
Ghent
Conveners: Christian Ohm, Kalliopi Petraki (Sorbonne Université), Ranny Budnik (Weizmann Institute of Science)-
116
Search for a stable six-quark state in $\Upsilon$ decays at $BABAR$
Recent investigations have suggested that the six-quark combination $uuddss$ could be a deeply bound state ($S$) that has eluded detection so far, and a potential dark matter candidate. We report the first search for a stable, doubly strange six-quark state in $\Upsilon \to S \bar{\Lambda} \bar{\Lambda}$ decays with the $BABAR$ experiment. No signal is observed, and limits on the combined $\Upsilon(2S,3S) \to S \bar{\Lambda} \bar{\Lambda}$ branching fraction set stringent limits on the existence of such exotic particles.
Speaker: Gerald Eigen (University of Bergen (NO)) -
117
The Light Dark Matter eXperiment, LDMX
The constituents of dark matter are still unknown, and the viable possibilities span a very large mass range. Specific scenarios for the origin of dark matter sharpen the focus on a narrower range of masses: the natural scenario where dark matter originates from thermal contact with familiar matter in the early Universe requires the DM mass to lie within about an MeV to 100 TeV. Considerable experimental attention has been given to exploring Weakly Interacting Massive Particles in the upper end of this range (few GeV – ~TeV), while the region ~MeV to ~GeV is largely unexplored. Most of the stable constituents of known matter have masses in this lower range, tantalizing hints for physics beyond the Standard Model have been found here, and a thermal origin for dark matter works in a simple and predictive manner in this mass range as well. It is therefore a priority to explore. If there is an interaction between light DM and ordinary matter, as there must be in the case of a thermal origin, then there necessarily is a production mechanism in accelerator-based experiments. The most sensitive way, (if the interaction is not electron-phobic) to search for this production is to use a primary electron beam to produce DM in fixed-target collisions. The Light Dark Matter eXperiment (LDMX) is a planned electron-beam fixed-target missing-momentum experiment that has unique sensitivity to light DM in the sub-GeV range. This contribution will give an overview of the theoretical motivation, the main experimental challenges and how they are addressed, as well as projected sensitivities in comparison to other experiments.
Speaker: Valentina Dutta (Univ. of California Santa Barbara (US)) -
118
Dark Sector Physics with Belle II
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is $8\times 10^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of data, a factor of 50 more than its predecessor. From February to July 2018, the machine has completed a commissioning run, achieved a peak luminosity of $5.5\times 10^{33}$ cm$^{-2}$s$^{-1}$, and Belle II has recorded a data sample of about 0.5 fb$^{-1}$. Main operation of SuperKEKB has started in March 2019.. Already this early data set with specifically designed triggers offers the possibility to search for a large variety of dark sector particles in the GeV mass range complementary to LHC and dedicated low energy experiments; these searches will benefit from more data in the process of being accumulated. This talk will review the state of the dark sector searches at Belle II with a focus on the discovery potential of the early data.
Speaker: Sam Cunliffe (DESY) -
119
Strong gravitational radiation from a simple dark matter model
A rather minimal possibility is that dark matter consists of the gauge bosons of a spontaneously broken symmetry. Here we explore the possibility of detecting the gravitational waves produced by the phase transition associated with such breaking. Concretely, we focus on the scenario based on a dark SU(2) group and argue that it is a case study for the sensitivity of future gravitational wave observatories to phase transitions associated with dark matter. This is because there are few parameters and those fixing the relic density also determine the effective potential establishing the strength of the phase transition. Particularly promising for LISA is the super-cool dark matter regime, with DM masses above 100 TeV, for which we find that the gravitational wave signal is notably strong. In our analysis, we include the effect of astrophysical foregrounds, which are often ignored in the context of phase transitions.
Speaker: Dr Iason Baldes (ULB) -
120
Phase transitions and gravitational waves in models of Z_N scalar dark matter
We study the nature of phase transitions and gravitational wave signals in models of scalar dark matter with Z_N symmetries. The scalar sector comprises the Standard Model Higgs, an Inert Doublet and a complex singlet. In such models, the dark matter relic density can be largely determined by semi-annihilations instead of usual annihilations, which reduces the direct detection signal. We perform a thorough study of the parameter space, investigating the impact of the quartic semi-annihilation couplings on the structure of potential minima, phase transitions, and possible enhancements of the stochastic gravitational wave signal.
Speaker: Mr Nico Benincasa -
4:10 PM
Coffee break
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121
Searches for dark matter with CMS
Searches for dark matter in various final states with invisible particles recoiling against standard model particles are presented. Various topologies and kinematic variables are explored, as well as jet substructure as a means of tagging heavy bosons. The focus of the talk is on the recent CMS results obtained using data collected in the LHC run 2.
Speaker: Isabelle De Bruyn (University of Wisconsin Madison (US)) -
122
Dark matter searches with the ATLAS detector
The presence of a non-baryonic dark matter (DM) component in the Universe is inferred from the observation of its gravitational interaction. If dark matter interacts weakly with the Standard Model (SM) it could be produced at the LHC. The ATLAS experiment has developed a broad search program for DM candidates. The results of recent searches on 13 TeV pp data, their interplay and interpretation will be presented, including in particular the recent interpretation in the context of a 2HDM+pseudoscalar model. Prospects for HL-LHC will also be discussed.
Speaker: Othmane Rifki (Deutsches Elektronen-Synchrotron (DE)) -
123
Global study of effective Higgs portal dark matter models using GAMBIT
In this talk, I'll present results from a global analysis of effective Higgs portal dark matter (DM) models in the frequentist and Bayesian statistical frameworks. In particular, we use the GAMBIT software to determine the preferred mass and coupling ranges for vector, Majorana and Dirac fermion DM models. We also assess the relative plausibility of all four (including scalar DM) models using Bayesian model comparison. Our analysis includes up-to-date likelihood functions for the DM relic density, invisible Higgs decays, and direct and indirect searches for weakly-interacting DM, including the latest XENON1T data. We also account for important systematic uncertainties arising from the local density and velocity distribution of DM, nuclear matrix elements relevant for direct detection, and Standard Model masses and couplings. From our global study, we find the parameter regions that can explain all of the DM and give a good fit to the observed data. The case of vector DM requires the most tuning and is therefore slightly disfavoured from a Bayesian point of view, whereas the fermionic DM case requires a strong preference for including a CP-violating phase which allows for a suppression of direct detection limits. Finally, we present $\mathsf{DDCalc~2.0.0}$, a tool for calculating direct detection observables and likelihoods for arbitrary non-relativistic effective operators. All of our results and samples are publicly available via Zenodo.
Speaker: Dr Ankit Beniwal (CP3, Université catholique de Louvain) -
124
Directional Dark Matter Search with Nuclear Emulsion
The NEWSdm experiment, based on nuclear emulsions, is proposed to measure the direction of WIMP-induced nuclear recoils. We discuss the potentiality, both in terms of exclusion limits and potential discovery, of a directional experiment based on the use of a solid target made by newly developed nuclear emulsions and read-out systems reaching sub-micrometric resolution. We also report results of the test exposure conducted in Gran Sasso last year.
Speaker: Giuliana Galati -
125
Searches for dark matter with the CRESST-III Experiment
CRESST-III is a cryogenic dark matter experiment operated at the Gran Sasso laboratory in Italy. The primary research interest is the search for dark matter in the sub-GeV mass region. Dark matter particles are detected by measuring the nuclear recoil energy from the elastic scatter with the dark matter particle. The experimental challenge for reaching such a low mass region is to achieve the lowest possible energy detection threshold. Currently CRESST-III has obtained an energy detection threshold of 30.1 eV. The target material is a 24g CaWO4-crystal operated at a temperature of about 15 mK and using a dual read-out scheme. By measuring the phonons and the scintillation light an active background suppression can be reached.
We will present spin-independent results from direct dark matter searches. We will discuss electromagnetic background sources and its composition, based on a Geant4-simulation. The simulation contains the CaWO4-crystal as well as the Cu-support structure. We will also discuss spin-dependent results obtained with a a CaWO4- and a Li2MoO4-crystal.
Finally we will present first results from a new data taking campaign, which started end of 2018 and will give an outlook of the future stages of the experiment.Speaker: Jochen Schieck (Austrian Academy of Sciences (AT)) -
126
Searching for Dark Matter with PICO-40L
PICO is an experiment using bubble chambers with superheated $\mathrm{C}_3\mathrm{F}_8$ to detect nuclear recoils caused by WIMP dark matter. Due to their inherent electron recoil rejection and ability to probe spin-dependent interactions using fluorocarbon targets, bubble chambers have an established niche in the field of dark matter direct detection. PICO-60 set world-leading limits on the WIMP-proton interaction cross section, though was background limited and saw excess events at the interface between the water buffer and active fluid. PICO-40L is the next phase of the experiment employing a new “right-side-up” design to eliminate the buffer and thereby remove these backgrounds, in addition to providing a proof-of-concept for the future PICO-500 detector. PICO-40L is being installed in the spring of 2019 and is expected to be collecting data during the summer. This talk will provide an overview of the experiment and discuss the current status of PICO-40L.
Speaker: Mr Clarke Hardy (Queen's University)
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116
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Detector R&D and Data Handling Campus Ledeganck - Aud. 4
Campus Ledeganck - Aud. 4
Ghent
Convener: Niko Neufeld (CERN)-
127
The PADME experiment
The PADME experiment at the Laboratori Nazionali di Frascati of INFN is designed to search for the gauge boson, A’, of a U(1) symmetry holding in a hidden sector of particles neutral under the Standard Model interactions.
The design performance of the experimental apparatus allows exploring the A’ mass range m< 23.7 MeV for values of the effective coupling between A’ and the photon ε>10^-3 using a positron beam impacting on a thin diamond target.
The PADME experiment has been in operation from October 2018 to February 2019 for a first detector and beam commissioning run. The statistics of the data sample collected could also allow the extraction of preliminary physics results.
The talk will review the experience gained with the detector and beam operation. In addition, the status of the understanding of the data in terms of detector performance, beam induced and physics background and, finally, the physics potential of PADME will be discussed.Speaker: Dr Gabriele Chiodini (INFN Lecce & Università del Salento (IT)) -
128
Detector Performances Studies at Muon Collider
The Muon Collider is a possible option for the next generation of high energy collider machines. It would permit to achieve the energy frontier in leptons collisions, without occurring in significative synchrotron radiation losses as in electrons rings.
Among the technological challenges in the realization of such machine, the treatment of the beam-induced background is one of the most critical issues for the detectors.
Beams with intensity spanning from 10^9 up to 10^11 muons per bunch are necessary to obtain the desired luminosity, therefore the muons decay rate is very high. Beam decay products and subsequent particles from secondary interactions with the machine elements can reach the interaction point, limiting the physical performances of the detector. This talk presents a study of the beam induced background for two beam energies and discuss possible strategies for its reduction in the light of new detectors technologies. A reconstruction strategy for a benchmark process, H->bb-bar, including the beam-induced background will be also illustrated as demonstration of the facility feasibility.Speakers: Donatella Lucchesi (INFN Padova), Donatella Lucchesi (Universita e INFN, Padova (IT)) -
129
Commissioning of the Cylindrical Drift Chamber for the COMET experiment
The COMET experiment at J-PARC searches for the neutrinoless coherent transition of a muon to an electron in the field of an aluminum nucleus, which violates the lepton flavor conservation and has never been observed yet so far. The conversion rate is predicted to be enhanced in new physics models beyond the Standard Model, while the process is extremely suppressed in the Standard Model. The goal of the COMET Phase-I is to explore the muon-to-electron conversion with a single event sensitivity of $3 \times 10^{-15}$, which is 100 times better than the current limit.
In the COMET Phase-I, the converted electrons, which possess monochromatic momentum of 105 MeV/$c$, are detected with a cylindrical drift chamber (CDC) in a solenoidal magnetic field of 1 T. An inevitable physical background is the decay-in-orbit electrons emitted from the normal 3-body muon decay in an atomic orbit. The momentum distribution of the decay-in-orbit electrons has a high-momentum tail which is able to reach nearly 105 MeV/$c$. In order to distinguish the signal from the background, good momentum resolution of 200 keV/$c$ is required. Therefore, the CDC is designed to reduce the amount of material to suppress the multiple scattering effect. We adopt a gas mixture of He:iC$_{4}$H$_{10}$ (90:10) as well as unplated 126-$\mu$m aluminum field wires and a 0.5-mm thin inner wall made of carbon-fiber-reinforced plastic. In addition, an alternated all stereo layer configuration for 20 layers in total is adopted to achieve good spatial resolution for the axial direction.
The construction of the CDC was successfully completed, and thereafter performance tests using cosmic rays are being carried out. We have achieved spatial resolution of 170 $\mu$m and efficiency of 95% so far. A future commissioning plan of the CDC will also be presented in this talk.
Speaker: Manabu Moritsu (KEK) -
130
Performances of multi-PMT photodetector for the Hyper-Kamiokande experiment
Hyper-Kamiokande, a 187~kton fiducial volume water Cherenkov detector to be built in Japan, is the next generation of the Super-Kamiokande experiment. Its broad physics program includes nucleon decay, neutrinos from astronomical and human-made beam, with the main focus to determine the leptonic CP violation. To detect the weak Cherenkov light generated by neutrino interactions or proton decay, the primary photo-detector candidate are 20-inch PMTs. In order to enhance the Hyper-Kamiokande physics sensitivity, the use of a smaller amount of mPMTs to be integrated in the 20" PMT configuration, is considered. A multi-PMT Optical Module based on a pressure vessel instrumented with multiple small diameter photosensors, readout electronics and power, offers several advantages as increased granularity, reduced dark rate, weaker sensitivity to Earth’s magnetic field, improved timing resolution and directional information with an almost isotropic field of view. In the first part of this talk, we will briefly present the multi-PMT modules developed for Hyper- Kamiokande. We will then show their positive impact on the sensitivity of the Hyper-Kamiokande Intermediate Water Cherenkov detector, which motivated their choice as the primary photosensor candidate. We will finally conclude by presenting the impact of these modules on the physics of the Hyper-Kamiokande far detector.
Speaker: Benjamin Quilain -
131
Performance of the SoLid reactor neutrino detector
Submitted for the SoLid Collaboration
Speaker: Luis Manzanillas (Centre National de la Recherche Scientifique (FR)) -
132
THE ELECTRONICS READOUT SYSTEM OF THE JUNO EXPERIMENT
The Jiangmen Underground Neutrino Observatory (JUNO) is a neutrino medium baseline experiment in construction in China, with the main goal to determine the neutrino mass hierarchy and to measure several neutrino mass and mixing parameters with a precision at the sub-percent level. The JUNO detector consists of 20 ktons of liquid scintillator contained in a 35 m diameter acrylic sphere, instrumented by more than 18000 20-inch photomultiplier tubes (PMTs), and about 25600 3-inch small PMTs. The required energy resolution to discriminate between the normal and inverted neutrino mass hierarchies at a 3-4 sigma CL for about 6 years of data taking is 3% at an energy of 1 MeV. This puts strong constraints on the detector component quality.
The JUNO electronics system can be separated into mainly two parts: the front-end electronics system performing analog signal processing (the underwater electronics), and after 100 meters Ethernet cables, the backend electronics system, sitting outside water, consisting of the DAQ and the trigger. For the front-end part, the electronics are located very close to the PMTs in order to minimize the length of cables and maximize the signal to noise ratio. The incoming analog signals from the PMTs are digitized in the Global Control Unit (GCU), contained in a water-tight box. Each underwater box is connected to three PMTs. The GCU is a custom Field Programmable Gate Array (FPGA) board with 3 ADU and 3 HV units. The digital signal and trigger informations are forwarded to the dry electronics by means of 100 m CAT5 Ethernet cable. For the back-end electronics part, back-end cards (BEC) are used as concentrators to collect and compensate the incoming trigger request signals and an FPGA mezzanine card handles all trigger request signals. The signals from the various BECs are sent to 21 RMU (Reorganise&Multiplex Unit) cards, and their sum is forwarded to the CTU (Central Trigger Unit). The main challenge of the whole electronics system is the very strict criteria on reliability: a maximum of 0.5% failure over 6 years for the PMT full readout chain.
The overall picture of the main parts of the JUNO detector, as well as its electronics readout system will be presented in this talk.
Speaker: Barbara Clerbaux (Universite Libre de Bruxelles (BE)) -
4:00 PM
Coffee break
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133
Characterisation of planar and 3D Silicon pixel sensors for the high luminosity phase of the CMS experiment at LHC
The High Luminosity upgrade of the CERN Large Hadron Collider (HL-LHC) calls for a new high-radiation tolerant solid-state pixel sensor, capable of surviving irradiation fluencies up to a 2.3 x 10^16 1 MeV equivalent neutrons per cm^2 at 3 cm from the interaction point. To this extent, the INFN ATLAS-CMS joint research activity, in collaboration with Fondazione Bruno Kessler, is aiming at the development of thin n-in-p type pixel sensors to be operated at the HL-LHC. The R&D covers both planar and single-sided 3D columnar pixel devices made with the Si-Si Direct Wafer Bonding technique, which allows for the production of sensors with 100 μm and 130 μm active thickness, for planar sensors, and 130 μm for 3D sensors, the thinnest ones ever produced so far. Prototypes of hybrid modules have been bump-bonded to the RD53A readout chip. The RD53A readout chip have been developed by the RD53 collaboration as a first step to the design of a readout chip for the pixel detectors of the ATLAS and CMS experiments during the high luminosity phase of the LHC. Test beam studies, both of thin planar and 3D devices, have been performed by the CMS collaboration at the Fermilab and CERN test beam facilities. First results of the modules performance before and after irradiation are reported in this presentation.
Speaker: Davide Zuolo (Universita & INFN, Milano-Bicocca (IT)) -
134
4D particle tracking with Resistive AC-Coupled Silicon Detectors
In this contribution we present the advantages of performing 4D particle tracking with Resistive AC-Coupled Silicon Detectors (RSD), a new paradigm in silicon detectors with moderate internal multiplication. Their design is an evolution of the standard LGAD (Low-Gain Avalanche Diode) technology, and is based on the combination of a resistive n-implant, freezing the multiplied charges, and a capacitive oxide layer, coupling the signal with the readout pads. Having a homogeneous gain layer throughout the detector, the spatial granularity is realized through the segmentation of pads, while the timing information directly benefits from the good performances given by the internal multiplication. Such scheme will allow to completely eliminate the signal loss between active areas (or pixels) proper of LGAD-based silicon trackers and to fully exploit the potentialities of high-luminosity scenarios foreseen in near-future colliders, thanks to their intrinsic 100% fill-factor (the ratio between the active and the total area).
After reviewing the RSD working principle and their design through numerical simulations, also a set of laboratory characterizations performed on the first production run RSD1 at Fondazione Bruno Kessler (FBK) will be presented, both before and after irradiation.Speaker: Marco Mandurrino (INFN) -
135
High time resolution, two-dimensional position sensitive MSMGRPC for high energy physics experiments
We will report our intense R\&D activity focused on the development of a Multi-Strip readout, Multi-Gap Resistive Plate Chamber (MSMGRPC), aiming to fulfil performance requirements of high energy physics experiments with high counting rate and high multiplicity environment.
Triggerless mode operation needed in a high interaction rate experiment requires a negligible noise or spurious signals from detectors and front-end electronics. Therefore, a close to perfect impedance matching between the detector and the electronics is mandatory and challenging for the counter design.
An innovative chamber design based on a method which gives the possibility to tune the characteristic impedance of the signal transmission line to the one of the FEE channel will be reported. The optimized design of the MGMSRPC prototype fulfils simultaneously two main, but antagonist, requirements for strip readout MRPCs: the granularity and the impedance matching to the front-end electronics.The results obtained with such a prototype in heavy ions in-beam tests (SIS18 - GSI Darmstadt and SPS - CERN), in triggered mode as well as in a free streaming readout operation, will be reported. The detector performance (i.e efficiency, time resolution, cluster size) in conditions of exposure of the whole active area of the chamber to high flux and high multiplicity reaction products are going to be discussed.
Based on the obtained performance, a layout of a small polar angle region of a fix target experiment, (e.g. CBM@FAIR TOF inner wall zone) was designed. A modular structure based on 12 modules of 4 types fit the uniform coverage of the active area. For a given strip pitch, the strip length can be adjusted in order to fulfil the required granularity as a function of polar angle. For this reason, each module contains up to three types of MRPCs. Module design, module integration and counter integration inside each module will be discussed.Speaker: Dr Mariana Petris (IFIN-HH) -
136
Fluoride production in CMS Resistive Plate Chambers (RPC) and long-term aging studies
The Resistive Plate Chambers (RPC) are gaseous detectors widely used in the muon trigger systems of LHC experiments. Gas mixtures based on HydroFluoroCarbon (HFC) components are generally used. The pollutants produced in the gas under high electrical discharge may accelerate the detectors aging, in particular the Fluorine ions (F-) produced in connection with Hydrogen Fluoride (HF) may damage the inner detector surface due to its high chemical reactivity. Dedicated measurements to estimate the HF production rate has been performed at the CERN Gamma Irradiation Facility (GIF++) operating a spare CMS-RPC detector at different background gamma rate and with different gas volumes changes. The HF trapped inside the detector gas volume has been also estimated. The HF deposited on the inner bakelite surface has been estimated operating the detector with pure Argon. The HF study results will be presented. In addition, in view of High Luminosity LHC (HL-LHC) period, a dedicated aging study is ongoing at GIF++, where few spare CMS-RPC detectors are exposed to an intense gamma radiation to estimate the impact of HL-LHC conditions, in order to confirm that the CMS-RPC system will survive to the harsher background rate expected at HL-LHC. The main detectors parameters (currents, rate, resistivity, etc.) are under monitoring as a function of the accumulated charge, and the performance studied with muon beam. After having collected a significant amount of the total irradiation preliminary results will be presented.
Speaker: Andrea Gelmi (Universita e INFN, Bari (IT)) -
137
Single Event Upsets in the ATLAS IBL Frontend ASICs at the Large Hadron Collider at CERN
ATLAS is one of the four major experiments at the Large Hadron Collider (LHC) at CERN. The tracking performance of the ATLAS detector relies critically on its 4-layer Pixel Detector, located at the core the ATLAS tracker.
During operation at instantaneous luminosities of up to 2 10^34/cm^2/s the
frontend chips of the ATLAS innermost pixel layer (IBL) experienced single
event upsets affecting its global registers as well as the settings for
the individual pixels, causing, amongst other things loss of occupancy,
noisy pixels, and silent pixels. A quantitative analysis of the single event
upsets as well as the operational issues and mitigation techniques will
be presented.Speaker: Peilian Liu (Lawrence Berkeley National Lab. (US)) -
138
Modeling Radiation Damage to Pixel Sensors in the ATLAS Detector
Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS detector at the Large Hadron Collider (LHC). As the closest detector component to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the High-Luminosity LHC (HL-LHC), the innermost layers will receive a fluence in excess of 10^15 neq/cm2 and the HL-HLC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. Simulating radiation damage is critical in order to make accurate predictions for current future detector performance that will enable searches for new particles and forces as well as precision measurements of Standard Model particles such as the Higgs boson. We present a digitization model that includes radiation damage effects to the ATLAS pixel sensors for the first time and considers both planar and 3D sensor designs. In addition to thoroughly describing the setup, we compare predictions for basic pixel cluster properties on leakage currents, depletion voltage, charge collection efficiency, Lorentz angle etc. with real data collected at LHC proton-proton collisions.
Speaker: Lorenzo Rossini (Università degli Studi e INFN Milano (IT)) -
139
Reconstruction in an imaging calorimeter for HL-LHC
The CMS endcap calorimeter upgrade for high luminosity LHC in 2025 uses, for the most part, silicon sensors to achieve radiation tolerance, with the further benefit of a very high readout granularity. Developing a reconstruction sequence that fully exploits the granularity, and other significant features of the detector like precision timing, is a challenging task. The aim is for operation in the high pileup environment of HL-LHC. An iterative clustering framework (TICL) is being developed. This takes as input clusters of energy deposited in individual calorimeter layers delivered by an "imaging" algorithm which has recently been revised and tuned to deliver excellent performance. Mindful of the projected extreme pressure on computing capacity in the HL-LHC era the algorithms are being designed with GPUs in mind. In addition, reconstruction based entirely on machine learning techniques is being developed and studied. This talk will describe the approaches being considered and show first results.
Speaker: Arabella Martelli (Imperial College (GB)) -
140
Exploring the structure of hadronic showers and hadronic energy reconstruction with highly granular calorimeters
Prototype imaging electromagnetic and hadronic calorimeters developed and operated by the CALICE collaboration provide an unprecedented wealth of highly granular data of hadronic showers for a variety of active sensor elements and different absorber materials. In this presentation, we discuss detailed measurements of the spatial and the time structure of hadronic showers to characterise the different stages of hadronic cascades in the calorimeters, which are confronted with GEANT4 - based simulations using different hadronic physics models. These studies also make use of the two different absorber materials, steel and tungsten, used in the prototypes. The high granularity of the detectors is also exploited in the reconstruction of hadronic energy, both in individual detectors and combined electromagnetic and hadronic systems, making use software compensation and semi-digital energy reconstruction. We will report on the performance of these reconstruction techniques for different electromagnetic and hadronic calorimeters, with silicon, scintillator and gaseous active elements.
Speaker: Imad Laktineh (Centre National de la Recherche Scientifique (FR))
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127
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Flavour Physics and CP Violation Campus Ledeganck - Aud. 6
Campus Ledeganck - Aud. 6
Ghent
Conveners: Admir Greljo, Angela Papa, Mitesh Patel (Imperial College (GB))-
141
ATLAS results on quarkonia and heavy flavour production
The associated production of vector boson with quarkonia is a key observable for understanding the quarkonium production mechanisms, including the separation of single and double parton scattering components.
This talk will present the latest measurements from ATLAS on quarkonium production, including associated production.Speaker: James William Walder (Lancaster University (GB)) -
142
Start of the Belle II Experiment at SuperKEKB: rediscovery of B Physics
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is $8\times 10^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of data, a factor of 50 more than its predecessor. With this data set, Belle II will be able to measure the Cabibbo-Kobayashi-Maskawa (CKM) matrix, the matrix elements and their phases, with unprecedented precision and explore flavor physics with $B$ and charmed mesons, and $\tau$ leptons. Regular operations with the full detector have successfully started on March 25, 2019. In this presentation, we will review the status of the Belle II detector, and discuss the first results; these, while confirming known B Physics, prove the detector ability and the software readiness to reach the experiment’s goals.
Speaker: Oskar Hartbrich (University of Hawaii at Manoa) -
143
Understanding charm CP
Recently LHCb announced the exciting discovery of direct CP asymmetry in D0 decays to K-pairs and pion pairs around 15X10^-4. It is extremely difficult to do reliable calculations for the expectations from the SM for these asymmetries because of large non-perturbative effects. However, a novel mechanism is proposed to helps us understand roughly the size of the asymmetry and the key idea readily leads to several testable predictions. Moreover, even though the original amplitudes for D^0 => h^+ h^- are extremely difficult to handle on the lattice using known techniques, a class of reactions with sizeable direct CP asymmetries where precise tests of the SM are possible will be discussed.
Speaker: AMARJIT Soni (BNL) -
144
Rare Charm decays at LHCb
LHCb is playing a crucial role in the study of rare and forbidden decays of charm hadrons, which are sensitive to effects beyond the Standard Model. New searches for FCNC-mediated processes and asymmetry measurements in multibody final states with two leptons are presented.
Speaker: Dominik Stefan Mitzel (CERN) -
145
Observation of the rare decay $D^0\to K^-\pi^+e^+e^-$
Flavor-changing neutral current (FCNC) processes are rare within the Standard Model (SM) as they cannot occur at tree level and are suppressed at loop level by the Glashow-Iliopoulos-Maiani (GIM) mechanism. In $D$-meson decays, the GIM cancellation is almost exact, leading to expected branching fractions for $c\to u l^- l^+$ processes of order $\mathcal{O}(10^{-9})$. However, long-distance effects can raise this to $\mathcal{O}(10^{-6})$. In this talk, we report on the observation of the $D^0\to K^-\pi^+e^+e^-$ decay, based on a sample of about 470 fb$^{-1}$ of data collected at or near the $\Upsilon(4S)$ resonance, with the $BABAR$ detector at the PEP II $e^+e^-$ collider.
We measure $\mathcal{B}(D^0\to K^-\pi^+e^-e^+) = (4.0\pm0.5)\times 10^{-6}$ in the di-lepton mass range $0.675< m(e^+e^-) < 0.875$ GeV$/c^{2}$, where the production of the intermediate state $\rho \to e^+e^-$ dominates, and set upper limits for decays outside this interval where long-distance effects are expected to be small. The result in the $\rho \to e^+e^-$ region is consistent with the recent observation of the analogous $D^0\to K^-\pi^+\mu^+\mu^-$ decay, reported by the LHCb Collaboration.Speaker: Fergus Wilson (Science and Technology Facilities Council STFC (GB)) -
4:00 PM
Coffee break
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146
Mixing and indirect CPV in Charm decays at LHCb
The large sample of charmed hadrons collected by LHCb is used to measure D0−D0bar mixing and to search for indirect CP violation as well as to measure direct CP violation in D0 mesons and Lambda_c+ baryons. New measurements from several decay modes are presented, including the first observation of CP violation in the charm system. We also discuss prospects for future sensitivities.
Speaker: Prasanthkrishnan Kodassery Padmalayammadam (Polish Academy of Sciences (PL)) -
147
Recent KLOE-2 results on kaon physics and discrete symmetries tests
The KLOE-2 experiment at the Frascati Laboratories of INFN
collected at the DA$\Phi$NE collider an integrated luminosity of 5.5 fb$^{-1}$ that
together with the 2.5 fb$^{-1}$ collected by its predecessor KLOE corresponds
to $\sim 8 \times 10^{9}$ $K_SK_L$ entangled pairs produced.
This is the world largest available data sample of this typology and represents a unique tool
to improve the precision in the study of the kaon properties and the fundamental discrete symmetries of nature.
The latest results on $K_S$ semileptonic decays, the measurement of their charge asymmetry - recently improved by about a factor of two with respect to the previous result - and related CP and CPT tests will be presented,
together with the results of the latest ongoing analyses on tests of Time reversal and CPT in kaon transitions, and the search for the CP violating KS->3pi0 decay.Speaker: Dr Daria Kisielewska (Jagiellonian University) -
148
A complete update of $\varepsilon'/\varepsilon$ in the Standard Model
The recent release of improved lattice data has revived again the interest on precise theoretical predictions for the direct CP-violation ratio $\varepsilon'/\varepsilon$. We present a complete update of the Standard Model prediction, including a new re-analysis of isospin-breaking corrections which are of vital importance in the theoretical determination of this observable. Contrary to recent claims, the Standard Model prediction turns out to be in good agreement with the experimental measurement. In addition, we analyse the prospects for future improvements on the current uncertainty, which is dominated by our current ignorance about $1/N_C$-suppressed contributions to some chiral-perturbation theory low-energy constants.
Speaker: Hector Gisbert Mullor (University of Valencia - IFIC) -
149
Latest measurement of K+→π+𝑣𝑣̅ with the NA62 experiment at CERN
The decay K+→π+𝑣𝑣̅, with a very precisely predicted branching ratio of less than 10-10, is one of the best candidates to reveal indirect effects of new physics at the highest mass scales. The NA62 experiment at the CERN SPS is designed to measure the branching ratio of the K+→π+𝑣𝑣̅ with a decay-in-flight technique. NA62 took data so far in 2016-2018. Statistics collected in 2016 allowed NA62 to reach the Standard Model sensitivity for K+→π+𝑣𝑣̅, entering the domain of 10-10 single event sensitivity and showing the proof of principle of the experiment. Thanks to the statistics collected in 2017, NA62 surpasses the present best sensitivity. The analysis strategy is reviewed and the preliminary result from the 2017 data set is presented.
Speaker: Nicolas Lurkin (University of Birmingham (GB)) -
150
Searches for lepton flavour and lepton number violation in K+ decays
The NA62 experiment at CERN collected a large sample of charged kaon decays into final states with multiple charged particles in 2016-2018. The sensitivity to a range of lepton flavour and lepton number violating kaon decays provided by this data set improves over the previously reported measurements. Results from the searches for these processes with a partial NA62 data sample are presented.
Speaker: Angela Romano (University of Birmingham (GB)) -
151
First observation and study of the K± → π±π0e+e− decay with the NA48/2 experiment at CERN
The NA48/2 experiment at CERN reports the first observation of the K± → π±π0e e− decay from an exposure of 1.7×1011 charged kaon decays recorded in 2003−2004. A sample of 4919 candidates with 4.9% background contamination allows the determination of the branching ratio in the full kinematic region. The study of the kinematic space shows evidence for a structure dependent contribution in agreement with predictions based on chiral perturbation theory. Several P- and CP-violating asymmetries are also evaluated.
Speaker: Giuseppina Anzivino (INFN and University of Perugia)
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141
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Heavy Ion Physics ICC - Baeckeland 1
ICC - Baeckeland 1
Ghent
Conveners: Guilherme Milhano (LIP-Lisbon & CERN TH), Iwona Grabowska-Bold (AGH University of Science and Technology (PL)), Yen-Jie Lee (Massachusetts Institute of Technology), You Zhou (University of Copenhagen (DK))-
152
(Anti-)nuclei production and flow in pp, p-Pb and Pb-Pb collisions with ALICE
High energy pp, p-Pb, and Pb-Pb collisions at the LHC offer a unique opportunity to study the production of light (anti-)nuclei. The study of the production yield of (anti-)nuclei in heavy-ion collisions at LHC energies probes the late stages in the evolution of the hot, dense nuclear matter created in the collision and serves as baseline in the search for exotic multi-baryon states.
Measurements performed in smaller collision systems are crucial to understand how the production mechanism evolves going from small to large systems.
The results on the determination of the (anti-)nuclei yields will be complemented by the measurement of their azimuthal anisotropic production. This is a powerful tool to gain insight into the production mechanism of light nuclei in heavy-ion collisions: in particular, it will help to distinguish between coalescence and hydrodynamic models.
The coalescence approach predicts light nuclei formation as the result of coalescence of nucleons which are close enough in the phase space, thus the elliptic and triangular flow are expected to scale with the number of constituent hadrons. On the other hand, if light nuclei are produced thermally at the phase boundary in heavy-ion collisions together with all the other hadrons, the evolution with transverse momentum of both elliptic and triangular flow can be described by hydrodynamic models.
Results on the production yields of light (anti-)nuclei in pp, p-Pb, and Pb-Pb collisions at energies going from 5.02 TeV to 13 TeV will be presented. In addition, new results on the measurement of the elliptic and the triangular flow of deuterons and 3He produced in Pb--Pb collisions at 5.02 TeV will be discussed. A critical comparison of the experimental results with the predictions of statistical (thermal) models and the baryon coalescence approach will be given.Speaker: Mr Sebastian Hornung (GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE)) -
153
Multiplicity and centre-of-mass energy dependence of light-flavor hadron production in pp, p-Pb, and Pb-Pb collisions with ALICE
The study of identified hadron production as a function of event multiplicity is a key tool for understanding the similarities and differences between large and small colliding systems.
The multiplicity-dependence of the total yields of identified hadrons as a function of event activity shows a remarkable scaling that covers all the collision systems considered.
The production rates of strange and multi-strange hadrons show enhancement patterns, which are not consistently captured by commonly-used Monte Carlo generators. To isolate the center-of-mass energy dependence, pp and Pb--Pb collisions have been measured at two different energies. We find that hadrochemistry is dominantly driven by the multiplicity in hadronic collisions at LHC energies, and not the colliding system or the center-of-mass energy.
We report on the production of pions, kaons, protons, K$^{0}_{\textrm{S}}$, $\Lambda$, $\Xi$ and $\Omega$ measured in pp ($\sqrt{s} = 7$ and $13$ TeV), p--Pb ($\sqrt{s_{\textrm{NN}}} = 5.02$ TeV) and Pb--Pb ($\sqrt{s_{\textrm{NN}}} = 2.76$ and $5.02$ TeV) collisions at the LHC. Results will be compared to predictions from hydrodynamic and statistical hadronization models.Speaker: Ivan Ravasenga (National Academy of Sciences of Ukraine (UA)) -
154
Recent results on spectator-induced electromagnetic effects in ultrarelativistic light- and heavy-ion collisions
We review our studies of spectator-induced electromagnetic (EM) effects on charged pion emission. For heavy-ion Pb+Pb and Au+Au reactions, we formulate a model which associates the size of EM effect with the space-time properties of the system of hot and dense matter formed in the collision. As a result we obtain an estimate for the pion decoupling time which agrees with pion decoupling times obtained from standard femtoscopy [1].
The first observation of the spectator-induced EM distortion of the $\pi^+ / \pi^-$ ratio in small systems at the CERN SPS [2] allows the extension of our study to Ar+Sc collisions at $\sqrt{s_{NN}} = 17.3\,\text{GeV}$. We improve our model description to take into account spectator fragmentation as well as the possible influence of the net positive participant charge close to the spectator system. This brings new information on the space-time evolution of pion production in small systems, and on the other hand allows us to study the interplay between spectator fragmentation and electromagnetic phenomena also in ultrarelativistic heavy-ion collisions.
A consistent picture of the space-time evolution of all the studied systems emerges, where the longitudinal evolution of the hot and dense matter created in the participant zone results in faster pions being produced closer to the spectator system.
[1] K. Aamodt et al., Phys. Lett. B 696, 328 (2011).
[2] A. Marcinek, EPJ Web Conf. 199, 02020 (2019).Speaker: Iwona Anna Sputowska (Polish Academy of Sciences (PL)) -
155
Kaon Isospin Fluctuations in Pb-Pb Collisions at $\sqrt{s_{NN}}$= 2.76 TeV with ALICE at the LHC
The first measurements of event-by-event correlated fluctuations of neutral and charged kaons are reported in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV, which are proposed to be related to isospin fluctuations in the kaon sector. These dynamic fluctuations affect the mechanism of correlated productions of neutral and charged kaons in heavy ion collisions. In this work we have used the robust statistical observable, $\nu_{dyn}$, to study the dynamical fluctuations in strangeness sector using charged and neutral kaons. A statistically significant signal of dynamical fluctuations is observed in the data which is underestimated by HIJING and AMPT model predictions, when moments of neutral and charged kaons are calculated as a function of centrality. We observed that $K_{s}^{0}-K^{\pm}$ fluctuations is not dominated by the correlation from particle decay like $K^{+}-K^{-}$.
Speaker: Ranjit Nayak (IIT- Indian Institute of Technology (IN)) -
156
Snapshots of fireballs at freeze-out from heavy-ion collisions at different energies
Identified hadron spectra from relativistic heavy-ion collisions allow
one to reconstruct the final state of the fireball. In principle, one
could deduce its previous evolution from a back extrapolation of the
final state. It is also important to study the collisions at different
energies, since hot matter at different energy and baryon densities is
created that way. One is then interested in any irregularities of the
collision energy dependence that might indicate the onset of
deconfinement or the vicinity of the critical point.We reconstruct the freeze-out state of the fireball produced in cental
Au+Au or Pb+Pb collisions in the energy range from 7.7 GeV up to 2760
GeV per colliding nucleon pair. The date stem from the RHIC beam energy
scan programme and from the LHC. Transverse momentum spectra of protons,
antiprotons, charged pions and kaons have been fitted with the blast-wave model that includes production via resonance decay. We present how
the composition of spectra looks at different energies as a function of
the transverse momentum. The freeze-out temperature decreases with
increasing collision energy, while the transverse expansion velocity
grows. The decrease of the freeze-out temperature seems to stop at the
collsion energy of 130 GeV; afterwards the temperature stays constant or
grows slightly.Speaker: Dr Ivan Melo (University of Žilina) -
4:00 PM
Coffee break
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157
Production of open heavy flavour hadrons in pPb collisions at LHCb
A rich set of open heavy flavour states is observed by LHCb in pPb collisions collected at 5 and 8.16 TeV nucleon-nucleon centre-of-mass energies. Thanks to the LHCb forward acceptance that is complementary to general purpose detectors, heavy-flavor hadrons can be studied down to zero transverse momentum. This talk presents production measurements of beauty hadrons and open charm states including baryons, through cleanly reconstructed exclusive decays. Results on nuclear effects, quantified by the nuclear modification factors, forward-to-backward production ratios and baryon-to-meson ratios, will be discussed.
Speaker: Yanxi Zhang (CERN) -
158
Investigating charm and beauty production and elliptic flow with leptons in Pb--Pb with ALICE
Heavy quarks (charm and beauty) constitute unique probes for the hot and dense QCD medium produced in heavy-ion collisions: the Quark-Gluon Plasma (QGP). They are mainly produced in hard scattering processes among partons, which occur immediately after the nuclei crossing with a time-scale shorter than the QGP formation time. Therefore, they witness the full evolution of the medium loosing energy while interacting with its constituents.
The measurement of the nuclear modification factor ($R_{\rm AA}$) of open heavy-flavour hadrons can provide important information about the properties of the parton in-medium energy loss. In this regard, of particular interest is the study of charm and beauty production separately so to assess the expected mass effect on the in-medium energy loss.Moreover, the measurement of the azimuthal anisotropies at low transverse momentum, quantified by the elliptic flow ($v_{\rm 2}$), gives insight into the participation of the heavy quarks in the collective expansion of the system and their possible thermalisation in the medium.
The ALICE detector is well suited to measure the production of leptons from heavy- flavour hadrons decays at mid- and forward rapidities. In particular, thanks to the excellent tracking and particle identification capabilities, at mid-rapidity ALICE can study electrons from beauty hadron decays. In this contribution, we report the latest measurements of the $v_{\rm 2}$ and $R_{\rm AA}$ of electrons from beauty hadron decays at mid rapidity in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$= 5.02 TeV. In addition the $v_{\rm 2}$ and $R_{\rm AA}$ of heavy-flavour hadrons decay muons at forward rapidity will be shown.
The experimental results will be compared with theoretical models.
Speaker: Martin Andreas Volkl (Eberhards Karls Universiy Tubingen (DE)) -
159
Measurement of open-charmed hadron production in Au+Au collisions at $\sqrt{s_\mathrm{NN}}$ = 200 GeV with the STAR experiment
In ultrarelativistic heavy-ion collisions at RHIC energies, the charm quarks are predominantly produced in initial hard partonic scatterings. Therefore, they experience the entire evolution of the hot and dense medium produced in these collisions, known as the Quark-Gluon Plasma (QGP), and make a very valuable probe. The STAR experiment is capable of studying the production of charm quarks and their interactions with the QGP through the reconstruction of the hadronic decays of D$^0$, D$^\pm$, D$_\textrm{s}$ and $\Lambda^\pm_\textrm{c}$ hadrons. These measurements were enabled thanks to the excellent pointing resolution of the Heavy Flavor Tracker (HFT). In this talk, we will present recent results of open-charmed hadron measurements in Au+Au collisions at $\sqrt{s_\textrm{NN}}=200$ GeV with the STAR experiment. In particular, we will discuss the nuclear modification factors of D$^\pm$ and D$^0$ mesons, which imply significant energy loss of charm quarks in the QGP, and D$^0$ elliptic and triangular flow coefficients which probe the charm quark transport in the QGP. We will also present the D$_\textrm{s}$/D$^0$ and $\Lambda^\pm_\textrm{c}$/D$^0$ yield ratios as functions of transverse momentum and collision centrality which help us better understand the charm quark hadronization process in heavy-ion collisions. Finally, we will show the rapidity-odd directed flow of D$^0$ mesons, which is sensitive to the initial tilt of the QGP bulk and can also probe the effects of the initial magnetic field in heavy-ion collisions.
Speaker: Mr Robert Licenik (Nuclear Physics Institute, Czech Academy of Sciences) -
160
Probing heavy quark dynamics in PbPb collisions with CMS
Measurements of heavy flavour hadrons in PbPb collisions provide information about the heavy quark dynamics inside the quark-gluon plasma (QGP). Heavy quarks are sensitive to the transport properties of the medium and may interact with the QCD matter differently from light quarks. At low pT, heavy quarks provide a direct window on the in-medium QCD force. At high pT, the comparison of results for light and heavy particles provides insights into the expected flavor dependence of in-medium parton energy loss. Recently, the CMS collaboration established a comprehensive heavy flavor program in heavy ion collisions including the detection of charm and beauty mesons. Using the large statistics heavy ion data samples collected during LHC Run2, high precision open charm and beauty measurements are performed over a wide transverse momentum range. In this talk, the first measurement of the radial distributions of D0 mesons in jets in PbPb and pp collisions is presented, sensitive to the energy loss and diffusion of charm quarks in the QGP. Such effects for the bottom quarks are probed with the measurement of D0 mesons from b hadron decays in pp and PbPb collisions. In addition, the hadronisation of charm quarks and the importance of coalescence are constrained with the study of Lambda_c baryons in pp and PbPb collisions. Finally, results on Ds and Bs production are reported and compared to D0 and B+ production, respectively, with implications on the importance of the recombination mechanism due to strangeness enhancement.
Speaker: Gabor Veres (Eotvos Lorand University (HU)) -
161
Attenuation of heavy flavors in a dense medium
Unexpectedly strong suppression of heavy flavored mesons, produced with high transverse momenta in heavy ion collisions, is caused by final state interactions in the created dense medium. Gluon bremsstrahlung by a highly virtual heavy quark ceases shortly after the hard collision in accordance with perturbative QCD calculations and LEP measurements of the fragmentation function. Nevertheless, within a dense medium hadronization lasts a much longer time than in vacuum, due to prompt multiple breakups of a large-size heavy-light meson, which has a very short mean free pass in the dense medium. This and the specific shape of the heavy quark fragmentation function explains the observed strong suppression of D and B mesons produced in heavy ion collisions.
Speaker: Boris Kopeliovich (UTFSM) -
162
Study of $R_{\rm AA}$ and $v_{2}$ of non-strange D mesons and D-jet production in Pb--Pb collisions with ALICE
The LHC heavy-ion physics program aims at investigating the properties of the Quark-Gluon Plasma (QGP) formed in such collisions. Heavy quarks (charm and beauty) are regarded as efficient probes to study and characterize the QGP, as they are created on a very short time scale in initial hard processes and subsequently experience the entire system evolution interacting with the medium constituents.
The measurement of the nuclear modification factor, $R_{\rm AA}$, of heavy-flavour particles gives important information about the colour-charge and parton-mass dependence of the energy loss as well as about possible modifications of heavy-quark hadronization in the medium. The heavy-flavour elliptic flow, $v_{2}$, provides insights on the degree of thermalization of heavy quarks in the medium at low $p_{\rm T}$ and the path-length dependence of parton energy loss at high $p_{\rm T}$, respectively. In addition, the study of heavy-flavour jets gives more direct access to the initial parton kinematics and can provide further constraints for heavy-quark energy loss mechanisms, in particular concerning the dissipation of the radiated energy in the medium.
In this talk, the latest results on the $p_{\rm T}$-differential $R_{\rm AA}$ and $v_{2}$ of non-strange D mesons in Pb--Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV performed with ALICE will be presented for different centrality classes and compared with theoretical model predictions. The results obtained with the Event-Shape Engineering (ESE) technique applied to the D-meson elliptic flow in semi-central Pb--Pb events to investigate the influence of initial geometry fluctuations on heavy-flavour production will be shown. Finally, the measurements of D-tagged jets in Pb--Pb collisions at $\sqrt{s_{\rm NN}}=5.02$~TeV will be discussed.
Speaker: Fabrizio Grosa (Politecnico di Torino (IT))
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152
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Higgs Physics Campus Ledeganck - Aud. 5
Campus Ledeganck - Aud. 5
Ghent
Conveners: Martin Flechl (Austrian Academy of Sciences (AT)), Ramona Groeber (HU Berlin), Sinead Farrington (University of Warwick (GB))-
163
Measurements of ttH and tH production at CMS
Most recent CMS results on Higgs boson production in association with top quarks will be presented.
Speaker: Cristina Martin Perez (Centre National de la Recherche Scientifique (FR)) -
164
Higgs boson production in association with a ttbar pair with the ATLAS detector
The measurement of Higgs boson production in association with a ttbar pair is essential to understand the top-quark couplings to the Higgs boson. This talk presents the analyses using Higgs boson decays to bbbar pairs, to two Z bosons, to other multi-lepton final states, and to a pair of photons, using pp collision data collected at 13 TeV.
Speaker: Antonio Policicchio (Sapienza Università di Roma and INFN ROMA1) -
165
Top-Higgs Associated Production involving $m_{A^0}$, $m_{H^0} \sim 300$ GeV
We revisit an old proposal where a pseudoscalar $A^0$ has mass between
$t\bar c$ and $t\bar t$ thresholds, but possess extra Yukawa couplings
by absence of $Z_2$ symmetry. With $\rho_{tt}$ small, it evades
$gg \to A^0 \to h^0(125)Z$ constraints, where approximate alignment
also helps. We find this scenario with relatively light $A^0$ is
not yet ruled out, and $cg \to tA^0 \to tt\bar c$ can probe sizable
$\rho_{tc}$ at the LHC. In a similar vein, we find that discovery
is possible for $m_H \sim$ 300 GeV for $cg \to tH^0 \to thh$, but would
need finite $h$-$H$ mixing angle $\cos\gamma$ to allow for finite
$\lambda_{Hhh}$ coupling, and $\rho_{tc}$ also needs to be not too
small. The latter could drive electroweak baryogenesis, which further
motivates the search.Speakers: Prof. George W.S. Hou (National Taiwan University), George Wei-Shu Hou (National Taiwan University (TW)) -
166
HH production at the High-Luminosity LHC with CMS
The High-Luminosity Large Hadron Collider (HL-LHC) is expected to deliver an integrated luminosity of up to 3000 fb-1. The very high instantaneous luminosity will lead to about 200 proton-proton collisions per bunch crossing (“pileup”) superimposed to each event of interest, therefore providing extremely challenging experimental conditions. CMS prospects on Higgs self-coupling measurements and HH production at the HL-LHC are presented.
Speaker: Sylvie Braibant-Giacomelli (Universita e INFN, Bologna (IT)) -
167
Searches for non-resonant HH production at CMS
The most recent results from searches for non-resonant production of Higgs boson pairs at CMS will be presented.
Speaker: Alessandra Cappati (Universita e INFN Torino (IT)) -
168
The Higgs self-coupling at CLIC
The Compact Linear Collider (CLIC) is a mature option for a future electron-positron collider operating at centre-of-mass energies of up to 3 TeV. CLIC will be built and operated in a staged approach with three centre-of-mass energy stages currently assumed to be 380 GeV, 1.5 TeV, and 3 TeV. The Higgs self-coupling is of particular interest: for determining the shape of the Higgs potential, and due to its sensitivity to a variety of BSM physics scenarios. At the higher-energy stages CLIC will produce Higgs boson pairs both via double Higgsstrahlung and via vector-boson fusion. Recent results will be presented showing that measurements of these processes lead to a determination of the Higgs self-coupling with a precision of around 10%.
Speaker: Ulrike Schnoor (CERN) -
4:00 PM
Coffee break
-
169
Search for di-Higgs production at 13 TeV and prospects for HL-LHC
The latest results on production of Higgs boson pairs at 13 TeV by the ATLAS experiment are reported, including a combination of six different decay modes. Results include bbtautau, bbbb, bbgamgam, bbWW, WWWW and WWgamgam final states, and they are interpreted both in terms of sensitivity to the SM and as limits on kappa_lambda, a scaling of the triple-Higgs interaction strength. Future prospects of testing the Higgs self-couplings at the High Luminosity LHC (HL-LHC) will also be presented.
Speaker: Francesco Costanza (Centre National de la Recherche Scientifique (FR)) -
170
Prospects for Higgs and precision SM physics with the ATLAS detector at the HL-LHC
The Large Hadron Collider (LHC) has been successfully delivering proton-proton collision data at the unprecedented center of mass energy of 13 TeV. An upgrade is planned to increase the instantaneous luminosity delivered by LHC in what is called HL-LHC, aiming to deliver a total of about 3000/fb of data to the ATLAS detector at a center of mass energy of 14 TeV. To cope with the expected data-taking conditions ATLAS is planning major upgrades of the detector.
In this contribution we present an overview of the precision physics measurement of the Standard Model, with particular focus on the electro-weak and Higgs sectors. Prospects for precision determination of Standard Model fundamental parameters, as the weak mixing angle, the Higgs couplings, di-Higgs observation, vector boson scattering processes, as well as measurement for rare Higgs decays are presented.
Such studies formed the basis of the ATLAS Collaboration input to the recent HL/HE-LHC Yellow-Report. An executive summary of this report was then submitted as input to the European Strategy process.
Speaker: Josh McFayden (CERN) -
171
Higgs boson rare and exotic decays at CMS
This talk will present the most recent results on CMS searches for Higgs boson rare and exotic decays.
Speaker: Fengwangdong Zhang (University of California Davis (US)) -
172
Search for rare and lepton flavor violating decays of the Higgs boson with the ATLAS detector
The Standard Model predicts several rare Higgs boson decay channels, which have not yet been observed, but that could enhanced in theories beyond the Standard Model. Among these are decays to second-generation leptons and quarks, H→mumu and H→cc, as well as decays to a Z boson and a photon, H->Zgamma. In addition, theories beyond the Standard Model may predict lepton-flavor violating decays of the Higgs boson. Results for these searches based on pp collision data collected at 13 TeV will be presented.
Speaker: Giovanni Marchiori (LPNHE Paris) -
173
Precision Higgs Physics at the International Linear Collider
The precision study of the 125 GeV Higgs boson offers a new window in to the search for new physics beyond the Standard Model. To confront the predictions of models with new interactions, it is important that the experimental program be designed to achieve 1% precision over the full spectrum of Higgs boson couplings, with minimal model-dependence in the analysis and with tight control of systematic errors. This talk will explain how a precision Higgs program with these capabilities can be achieved at the proposed International Linear Collider. We will compare the capabilities of the ILC to those of the high-luminosity LHC and to those of other e+e- Higgs factory proposals.
Speaker: Dr Shin-ichi Kawada (DESY) -
174
Probing the dark sector via searches for invisible decays of the Higgs boson at the ILC
To unravel the nature of dark matter is one of the most important goals in particle physics today. The Higgs field may well be the portal that couples to a whole new dark sector in which the dark matter candidate particle is accommodated. Searches for invisible decays of the Higgs boson, which may originate from the Higgs boson decaying to dark matter directly or via some mediator, would give us a clear signal of new physics. At e+e- colliders, taking advantage of the recoil mass technique, the 4-momentum of the Higgs boson can be fully reconstructed even though it decays invisibly. A specific advantage of the ILC are the polarized beams which help to suppress the background significantly. We will report our studies based on the full simulation of the ILD detector concept, using the e+e- -> ZH with Z->qq/ll channels. We obtain a sensitivity to BR(H->invisible) of 0.3% (95% C.L. upper limit) at the ILC 250 GeV with an integrated luminosity of 2 ab-1. We will also discuss the impact of center-of-mass energy, beam spectrum, ISR, and detector performance for the Higgs to invisible measurement.
Speaker: Mr Yu Kato (The University of Tokyo) -
175
Probing Higgs Sector New Physics in Vector Boson Longitudinal Mode
Off-shell Higgs at the high mass tail may shed light on the underlying mechanism of the electroweak symmetry breaking. In the Standard Model, there is an exact cancellation of the logarithmic divergence between the box and Higgs-mediated triangle diagrams due to unitarity, such that the gg to ZZ(WW) process in the SM is dominated by the vector boson transverse-mode. The cancellation can be delayed to a higher scale, when there is sufficiently large new physics contribution resulting in VLVL longitudinal mode, which is commonly the case when the Higgs sector is modified. Thus the longitudinal mode in the high mass tail can be utilized as a sensitive probe for new physics. We thus propose to utilize the information in angular observables to maximize the sensitivity across various types of Higgs sector new physics.
Speaker: Zhuoni Qian (IBS)
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163
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QCD and Hadronic Physics ICC - Baeckeland 3
ICC - Baeckeland 3
Ghent
Conveners: Bogdan Malaescu (Centre National de la Recherche Scientifique (FR) & CERN), Gabor Veres (Eotvos Lorand University (HU)), Marek Schoenherr (University of Durham), Mikko Voutilainen (Helsinki Institute of Physics (FI))-
176
The role of angular ordering condition in Parton Branching transverse momentum dependent (TMD) PDFs and DY transverse momentum spectrum at LHC
We discuss the parton branching (PB) evolution equation for transverse momentum dependent (TMD) parton distribution functions (PDFs), especially we concentrate on the angular ordering constrain and its effect on the TMD distributions.
We discuss application of the PB TMDs to precise prediction of Drell-Yan transverse momentum spectrum at LHC, especially we stress the role of angular ordering in the low transverse momentum region.
We compare the PB implementation of the angular ordering condition with the Kimber-Martin-Ryskin-Watt (KMRW) and the Collins-Soper-Sterman (CSS) approaches, both at the analytical and numerical level.
Speaker: Aleksandra Lelek (University of Antwerp (BE)) -
177
Exotic and Conventional Quarkonium Physics Prospects at Belle II
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is $8\times 10^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of data, a factor of 50 more than its predecessor. From February to July 2018, the machine has completed a commissioning run and main operation of SuperKEKB has started in March 2019. Belle II is uniquely capable of studying the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks. First discovered by Belle, these now number in the dozens, and represent the emergence of a new category within quantum chromodynamics. This talk will present the prospects of Belle II to explore both exotic and conventional quarkonium physics.
Speaker: Klemens Lautenbach (Giessen University) -
178
Pseudoscalar current transition form factors of the delta in baryon chiral perturbation theory
We present the chiral corrections to the pseudoscalar current transition form factors of the delta in relativistic baryon chiral perturbation theory up to third chiral order using the complex-mass renormalization scheme (CMS) to generate a systematic power counting. We analyze the form factors $\tilde{g}(q^2)$ and $\tilde{h}(q^2)$ which are relevant to address the $\pi \Delta \Delta$ coupling constants at $q^2=0$. Knowledge on these form factors are necessary as there is no clear available experimental data for the pseudoscalar current-delta transition form factors which makes the topic still up to date for both experimental and theoretical studies.
\par
This study was supported by \c{C}anakkale Onsekiz Mart University Scientific Research Projects Commission under the grant no: FBA-2018-2666.}\\textbf{Keywords:} Baryon chiral perturbation theory, CMS, delta resonance, form factors.
Speaker: Dr Yasemin Ünal (Çanakkale Onsekiz Mart University) -
179
The ${\gamma^* \gamma^* \to \eta_c (1S,2S)}$ transition form factor from quarkonium wave functions
We discuss $\gamma^* \gamma^* \to \eta_c(1S)\, , \,\eta_c(2S)$ transition form factor for both virtual photons. The general formula is given. We use different models for the $c \bar c$ wave function obtained from the solution of the Schr\"odinger equation for different $c \bar c$ potentials: harmonic oscillator, Cornell, logarithmic, power-law, Coulomb and Buchm\"uller-Tye. We compare our results to the BaBar experimental data for $\eta_c(1S)$, for one real and one virtual photon. We discuss approaching of $Q_1^2 F(Q_1^2,0)$ or $Q_2^2 F(0,Q_2^2)$ to their asymptotic value $\frac{8}{3}f_{\eta_{c}}$ predicted by Brodsky and Lepage formalism. We discuss applicability of the collinear and/or massless limit and delayed onset of asymptotic behaviour.
We present some examples of two-dimensional distributions for $F_{\gamma^* \gamma^* \to \eta_c}(Q_1^2,Q_2^2)$. A scaling in $\omega = (Q_1^2 = Q_2^2) / (Q_1^2 + Q_2^2)$ was obtained. A factorization breaking measure is proposed and factorization breaking effects are quantified and shown to be weakly model dependent.Speaker: Ms Izabela Babiarz (Institute of Nuclear Physics, Polish Academy of Sciences) -
180
The onset of spin rotation effects in electroproduction of heavy quarkonia
We study manifestations of the Melosh spin rotation effects in diffractive electroproduction of heavy quarkonia off a nucleon target.
The quarkonia wave functions are determined within the Schroedinger equation based formalism using realistic potentials, which describe the interaction between heavy quark and antiquark.
The large importance of the Melosh spin transformation is analysed within the color dipole approach using several popular parametrizations of the dipole cross section.
We find that a strong onset of spin rotation effects in 1S charmonium photoproduction, obviously neglected in present calculations, contributes to obtaining a reasonable agreement with available data
For the photoproduction of radially excited 2S (3S) quarkonia these effects are even stronger as a direct manifestation of the nodal structure of their wave functions (the node effect).
They lead to a rise of the $ \Psi'(2S) $ photoproduction cross section by a factor of 2-3 causing so a substantial enhancement of the $\Psi'(2S)$-to-$J/\Psi(1S)$ ratio of the photoproduction cross sections to the values close to experimental data.
However, for the radially excited bottomonia $\Upsilon'(2S)$ and $\Upsilon''(3S)$, they enhance the corresponding photoproduction cross sections by a smaller factor of 1.2-1.3 due to a weaker node effect.
Finally, we predict that the spin effects vanish gradually with photon virtuality $Q^2$ with the universal onset in the production of different heavy quarkonia at the same fixed values of $Q^2+M_V^2$.
Speaker: Dr Michal Krelina (FNSPE, Czech Technical University) -
181
Color-allowed Bottom Baryon to $s$-wave and $p$-wave Charmed Baryon non-leptonic Decays
We study color allowed $\Lambda_b\to \Lambda^{(*,**)}_c M^-$, $\Xi_b\to\Xi_c^{(**)} M^-$ and $\Omega_b\to\Omega^{(*,**)}_c M^-$ decays with $M=\pi, K, D, D_s, \rho, K^*, D^*, D^*_s, a_1$ and $s$-wave and $p$-wave charmed baryons, including $\Lambda^{(*,**)}_c=\Lambda_c, \Lambda_c(2595), \Lambda_c(2625), \Lambda_c(2765), \Lambda_c(2940)$,$\Xi_c^{(**)}=\Xi_c, \Xi_c(2815), \Xi_c(2790)$ and $\Omega^{(*,**)}_c=\Omega_c, \Omega_c(2770), \Omega_c(3050), \Omega_c(3090), \Omega_c(3120)$, in this work. There are six types of transitions, namely (i) ${\cal B}_b({\bf \bar 3_f},1/2^+)$ to ${\cal B}_c({\bf \bar 3_f},1/2^+)$, (ii) ${\cal B}_b({\bf 6_f},1/2^+)$ to ${\cal B}_c({\bf 6_f},1/2^+)$, (iii) ${\cal B}_b({\bf 6_f},1/2^+)$ to ${\cal B}_c({\bf 6_f},3/2^+)$, (iv) ${\cal B}_b({\bf 6_f},1/2^+)$ to ${\cal B}_c({\bf 6_f},3/2^-)$, (v) ${\cal B}_b({\bf \bar 3_f},1/2^+)$ to ${\cal B}_c({\bf \bar 3_f},1/2^-)$, and (vi) ${\cal B}_b(\bar {\bf 3_f},1/2^+)$ to ${\cal B}_c({\bf 6_f},3/2^-)$ transitions. The light diquarks are spectating in these transitions.
The bottom baryon to charmed baryon form factors are calculated using the light-front quark model. All of the form factors in the $1/2\to 1/2$ and $1/2 \to 3/2$ transitions are extracted. They are found to reasonably satisfy the relations obtained in the heavy quark limit, as we are using heavy but finite $m_b$ and $m_c$. Decay rates and up-down asymmetries are predicted using naive factorization and can be checked experimentally. The study on these decay modes may shed light on the quantum numbers of some of the charmed baryons.Speakers: Chun-Khiang Chua, Chung Tah Chua (Nanyang Technological University) -
4:00 PM
Coffee break
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182
Physics at FCC-ee
The future circular collider (FCC) study released a conceptual design report (CDR) in January 2019. An electron machine is considered as a first step (FCC-ee) with up to four detectors. FCC-ee is capable of very high luminosities in a wide center-of-mass (ECM) spectrum from 90 to 365 GeV. FCC-ee provides a clean experimental environment, produces high luminosity for precision measurements of the Higgs boson, W and Z bosons, and the top-quark. Precision searches will test the consistency of the Standard Model and push the sensitivity to new physics at high scales.
Speaker: Tadeusz Lesiak (Polish Academy of Sciences (PL)) -
183
Precision QCD with the LHeC and the FCC-eh
The Large Hadron-electron Collider (LHeC) is a proposed upgrade of the LHC at CERN. It consists of an ERL providing electrons to collide with the HL-LHC, HE-LHC and the FCC-hh proton beams. These ep configurations will achieve centre-of-mass energies 1.3-3.5 TeV and luminosities $\sim 10^{34}$ cm$^{−2}$ s$^{-1}$ which extends the HERA kinematic coverage by more than one order of magnitude towards smaller $x$ and larger $Q^2$. DIS measurements in such machines will greatly enlarge our knowledge on parton densities through a complete unfolding of all flavours in a single experimental setup, to be compared with data from hadron colliders as an independent input and as a test of factorisation. They will also allow a very precise determination of $\alpha_s$. In this talk we review the most recent developments on these subjects.
Speaker: Amanda Sarkar (University of Oxford (GB)) -
184
QCD Monte Carlo model tuning studies with CMS data at 13 TeV
New CMS PYTHIA 8 event tunes are presented. The new tunes are obtained using minimum bias and underlying event observables exploiting Monte Carlo configurations with consistent parton distribution functions and strong coupling constant values in the matrix element and the parton shower, at leading order (LO), next-to-leading order (NLO) and next-to-next-to-leading order (NNLO). Validation and performance studies are presented by comparing the predictions of the new tunes to a wide range of different CMS measurements at 7, 8 and 13 TeV with CMS.
Speaker: Roberto Covarelli (University/INFN Torino (IT)) -
185
Measurements of multiparton interactions at ATLAS
Measurements of multiple parton scattering in proton-proton collisions provide insight into the structure and long-range low-momentum scale interactions of the proton. In this talk we present two recent measurements using proton-proton collision data collected by the ATLAS experiment. The first measurement determines the double-parton scattering contribution to four-lepton events at √s=8 TeV. An artificial neural net is used to optimise the analysis and an upper limit on the double-parton scattering fraction is set at 0.042, which corresponds to an effective cross section of 1mb. In the second measurement, the underlying event activity is studied in events containing a Z-boson in √s=13 TeV data. Unfolded differential cross sections are presented for charged particle multiplicity and charged particle transverse momentum in regions of azimuth measured with respect to the Z-boson direction. The data are compared to a wide variety of predictions from Monte Carlo event generators.
Speaker: Tim Martin (University of Warwick (GB)) -
186
Determination of proton parton distribution functions using ATLAS data
We present fits to determine parton distribution functions (PDFs) using top-antitop, inclusive W/Z-boson, as well as W+ and W− boson production measurements in association with jets from ATLAS, in combination with deep-inelastic scattering data from HERA. The ATLAS W and Z boson data exhibit sensitivity to the valence quark distributions and the light quark sea composition, whereas the top-quark pair production data have sensitivity to the gluon distribution. The impact of the top-antitop production data is increased by fitting several distributions simultaneously, with the full information on the systematic and statistical correlations between data points. The parton distribution functions extracted using W+jets data show an improved determination of the high-x sea-quark densities, while confirming the unsuppressed strange-quark density at lower x<0.02 found by previous ATLAS analyses.
Speaker: Francesco Giuli (INFN e Universita Roma Tor Vergata (IT)) -
187
PDF Profiling Using the Forward-Backward Asymmetry in Neutral Current Drell-Yan
Non-perturbative QCD effects from Parton Distribution Functions (PDF) at hadron colliders may be constrained by using high statistics Large Hadron Collider (LHC) data. Drell-Yan (DY) measurements in the Charged Current (CC) case provide one of the primary channels to do this, in the form of the lepton charge asymmetry. We investigate here the impact of measurements in Neutral Current (NC) DY data mapped in the Forward-Backward Asymmetry ($A_{\rm FB}$) on PDF determinations, by using the open source fit platform xFitter. We find that $A_{\rm FB}$ enables new PDF sensitivity and present results showing this in presence of a thorough uncertainty analysis.
Speaker: Dr Francesco Giuli (INFN e Universita Roma Tor Vergata (IT)) -
188
Further studies of isolated photon production with a jet in deep inelastic scattering at HERA
Isolated photons with high transverse energy have been studied in deep inelastic $ep$ scattering with the ZEUS detector at HERA, using an integrated luminosity of $326\, \mathrm{pb}^{-1}$ in the range of exchanged-photon virtuality $10 - 350 \,\, \mathrm{GeV}^2$. Outgoing isolated photons with transverse energy $4 < E_T^\gamma < 15$ GeV and pseudorapidity $-0.7 < \eta^\gamma < 0.9$ were measured with accompanying jets having transverse energy and pseudorapidity $2.5 < E_T^{\rm jet} <35$ GeV and $-1.5< \eta^{\rm jet} < 1.8$, respectively. Differential cross sections are presented for the following variables: the fraction of the incoming photon energy and momentum that is transferred to the outgoing photon and the leading jet; the fraction of the incoming proton energy transferred to the photon and leading jet; the differences in azimuthal angle and pseudorapidity between the outgoing photon and the leading jet and between the outgoing photon and the scattered electron. Comparisons are made with theoretical predictions: a leading-logarithm Monte Carlo simulation, a next-to-leading-order QCD prediction, and a prediction using the $k_T$-factorisation approach.
Speaker: Katsuo Tokushuku (High Energy Accelerator Research Organization (JP))
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176
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Quantum Field and String Theory ICC - Baeckeland 2
ICC - Baeckeland 2
Ghent
Convener: Miguel Montero (KU Leuven)-
189
Quantum Yang-Mills vacua in expanding Universe: Do we live in a time crystal?
The dynamical cancellation of the vacuum energy of the QCD sector in the infrared regime is a relevant problem for both particle physics and cosmology. We find an argument related to the existence of Z2-symmetry for the renormalization group flow derived from the bare Yang-Mills Lagrangian, and show that the cancellation of the vacuum energy may arise motivated both from the renormalization group flow solutions and the effective Yang-Mills action. At the cosmological level, we explore the stability of the electric and magnetic attractor solutions, both within and beyond the perturbation theory, and find that thanks these latter the cancellation between the electric and the magnetic vacua components is achieved at macroscopic space and time separations. This implies the disappearance of the conformal anomaly in the classical limit of an effective Yang-Mills theory while a local breakdown of time-translation invariance highlights the formation of a time-crystal grounds-state as a result of the QCD phase transition. A new type of non-perturbative non-local configurations in the Yang-Mills vacua, space-time instanton-like objects separated by domain walls, is emerged and their properties and implications (e.g. for gravitational-wave echoes of the QCD transition) are discussed.
Speaker: Roman Pasechnik (Lund university) -
190
Distinguishing black hole microstates: bulk and boundary perspectives
Within supergravity (the low energy effective theory of string theory) there exist non-singular, horizonless solutions, called fuzzballs, with asymptotic charges $M$, $J$, $Q$ coincident with the charges of a black hole. Two immediate questions arise: 1) Are these solutions viable candidates for microstates that make up the black hole entropy? 2) Can humans (asymptotic observers) distinguish between these solutions? In this talk I will report on our recent progress to answering these questions within the framework of AdS/CFT for a toy model for such microstate: an AdS generalization of the Damour-Solodukhin wormhole. In particular we calculate the quazi-normal modes in that geometry and relate them to poles of CFT correlators via the AdS/CFT dictionary. Then we study how close are these correlators to the thermal correlator (that is the standard black hole result) and comment on whether thermality bounds such as the eigenstate thermalization hypothesis allow for these solutions to enter in the black hole ensemble.
Speaker: Mr Vasil Dimitrov (KU Leuven) -
4:00 PM
Coffee break
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191
SOME QUANTUM-MECHANICAL RELATIONS IN CASE OF SINGULAR OPERATORS
Elaboration of some fundamental relations in 3-dimensional quantum mechanics is
considered taking into account the restricted character of areas in radial distance. In such cases
the boundary behavior of the radial wave function and singularity of operators at the origin of
coordinates contribute to these relations. We derive the relation between the average value of the
operator’s time derivative and the time derivative of the mean value of this operator, which is
usually considered to be the same by definition. The deviation from the known result is deduced
and manifested by extra term, which depends on the boundary behavior mentioned above. The
general form for this extra term takes place in the hypervirial-like theorems. As a particular case,
the virial theorem for Coulomb and oscillator potentials is considered and correction to the
Kramers’ sum rule is derived. Moreover the corrected Ehrenfest theorem is deduced and its
consistency with real physical picture is demonstrated.Speaker: Prof. Teimuraz Nadareishvili (Iv.Javakhishvili Tbilisi State University) -
192
Orbital angular momentum in photon-photon scattering
Photon-photon scattering in vacuum is one of the oldest and most intriguing predictions of quantum electrodynamics, as it would confirm what is called "vacuum polarization" and change our perception of the electromagnetic vacuum. However, experimental verification of scattering between real photons in vacuum hasn't materialized yet. This is due, in part, to the relative weakness of this interaction. Several proposals have been put forth to attempt to detect this effect, including using high-power lasers which compensate the relatively low energy of their photons with the ultra-high intensities they can achieve. With the advent of new multi-petawatt laser facilities, such as ELI and APOLLON, an experiment to detect photon-photon scattering using high-power lasers is looking increasingly feasible. However, these types of experiments still need to find a way to increase the relatively low signal-to-noise ratio caused by the large amount of background radiation coming from unwanted effects such as inverse Compton scattering. To this end, we have investigated the effect of orbital angular momentum (OAM) on elastic photon-photon scattering in vacuum for the first time. We defined exact solutions to the vacuum electromagnetic wave equation which carry OAM. Using those, the expected coupling between three initial waves has been derived in the framework of an effective field theory based on the Euler-Heisenberg Lagrangian which has shown that OAM adds a signature to the generated photons thereby greatly improving the signal-to-noise ratio. This forms the basis for a proposed high-power laser experiment utilizing quantum optics techniques to filter the generated photons based on their OAM state. This would allow the detection of these rare scattering events on the previously mentioned multi-petawatt systems thereby finally providing experimental proof for elastic photon-photon scattering in vacuum.
Speaker: Mr Ramy Aboushelbaya (Ramy) -
193
Mathematical aspects of the scattering amplitude for $H\to gg$ within the loop-tree duality
The phenomenological application of the Higgs boson production via gluon fusion has been extensively studied in the full theory of the standard model and in the effective field theory approach where the Higgs boson couples directly to gluons. The latter is straightforwardly obtained by considering the heavy top mass limit. In this talk, following the ideas of universal dual amplitudes in the loop-tree duality formalism [Eur.Phys.J. C78 (2018) no.3, 231], we analyse the one-loop amplitude $H\to gg$ in the large top mass limit. In fact, we show that independently of the particles running in the loop (scalar, quarks, vector bosons and gluons), we recover the same functional structure. We present the decay width of $H\to gg$, in which local UV renormalisation and local IR cancellation are done by means of the four-dimensional-unsubtraction method.
Speaker: William Javier Torres Bobadilla (IFIC CSIC-UV) -
194
Towards two-loop computations in four dimensions with the Loop-Tree Duality
We propose a new algorithm based on the Loop-Tree Duality theorem to renormalise and calculate two-loop diagrams. The ultraviolet singularities are locally cancelled in a systematic way and at the integrand level, allowing for a full four-dimensional numerical implementation of the method. In particular, we apply the method to calculate the $H\to\gamma\gamma$ amplitude at two-loop level, and find an excellent agreement with already available literature results. We also present other advantages of the Loop-Tree Duality formalism, such as the possibility to write unintegrated amplitudes in a universal way, regardless of the particle running inside the loop.
Speaker: Félix Driencourt-Mangin (IFIC, UV-CSIC) -
195
Analysis of singularities and the four-dimensional representation > of physical observables within the LTD formalism
In the past years, we have been developing a novel technique, called Four-Dimensional Unsubtraction (FDU) which aims to obtain purely four-dimensional representations of the matrix elements contributing to physical observables. In this talk, we describe the application of the loop-tree duality (LTD) theorem to represent loop amplitudes in terms of tree-level like objects, focusing on the origin of possible singularities of scattering amplitudes. In particular, we analyse the regions responsible of infrared and threshold singularities. With this information, we aim to extend the FDU formalism to NNLO and beyond.
Speaker: German Sborlini (IFIC CSIC-UV) -
196
Off-shell Jacobi currents within the loop-tree duality
Scattering amplitudes in gauge theories display important applications for the calculation of observables in the physics that the LHC delivers and, also, formal properties where mathematical aspects are considered. In this talk we consider relations among scattering amplitudes that are obtained as a consequence of the duality between colour and kinematics. These relations are obtained from Jacobi-like identities of kinematic numerators. Hence, we show that the generation of off-shell currents, with a clever choice of the gauge, allows for finding integral relations as a byproduct of this duality. On top of it, we rely on the loop-tree duality formalism to systematise the derivation of these relations. Analytic examples in QCD are presented.
Speaker: Dr William Javier Torres Bobadilla (IFIC CSIC-UV)
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189
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Searches for New Physics Campus Ledeganck - Aud. 1
Campus Ledeganck - Aud. 1
Ghent
Conveners: Christina Jane Potter (University of Cambridge (GB)), David Marzocca (INFN Trieste), Robert Schoefbeck (Austrian Academy of Sciences (AT))-
197
Searches for leptoquarks in CMS
We present latest results from searches for leptoquarks with the CMS detector. A variety of final states is considered, probing leptoquark couplings to all three generations of quarks and leptons.
Speaker: Francesco Romeo (Vanderbilt University) -
198
Searches for new phenomena in final states involving leptons and jets using the ATLAS detector
Many theories beyond the Standard Model predict new phenomena which decay to final states containing both leptons and jets. Searches for new physics models with these signatures are performed using the ATLAS experiment at the LHC. The results of the most recent searches on 13 TeV pp data will be presented.
Speaker: Adriana Milic (University of Toronto (CA)) -
199
Limits on contact interactions and leptoquarks at HERA
High-precision HERA data corresponding to a luminosity of around 1 fb$^{-1}$ have been used in the framework of $eeqq$ contact interactions (CI) to set limits on possible high-energy contributions beyond the Standard Model to electron-quark scattering. Measurements of the inclusive deep inelastic cross sections in neutral and charged current $ep$ scattering were considered. The analysis of the $ep$ data has been based on simultaneous fits of parton distribution functions including contributions of CI couplings to $ep$ scattering. Several general CI models and scenarios with heavy leptoquarks were considered. Improvements in the description of the inclusive HERA data were obtained for a few models. Since a statistically significant deviation from the Standard Model cannot be established, limits in the TeV range were set on all models considered.
Speaker: Aleksander Filip Zarnecki (University of Warsaw) -
200
Phenomenology of TeV-scale scalar Leptoquarks in the EFT
We examine new aspects of leptoquark (LQ) phenomenology using effective field theory (EFT). We construct a complete set of leading effective operators involving SU(2) singlets scalar LQ and the SM fields up to dimension six. We show that, while the renormalizable LQ-lepton-quark interaction Lagrangian can address the persistent hints for new physics in B-decays and the anomalous magnetic moment of the muon, the LQ higher dimensional effective operators may lead to new interesting effects associated with lepton number violation. These include the generation of one-loop sub-eV Majorana neutrino masses, mediation of neutrinoless double-$\beta$ decay and novel LQ collider signals. For the latter, we focus on 3rd generation LQ ($\phi_3$) in a framework with an approximate $Z_3$ generation symmetry, and show that one class of the dimension five LQ operators may give rise to a striking asymmetric same-charge $\phi_3 \phi_3$ pair-production signal, which leads to low background same-sign leptons signals at the LHC. For example, with $M_{\phi_3} \sim 1$ TeV and a new physics scale of $\Lambda \sim 5$ TeV, we expect about $5000$ positively charged $\tau^+ \tau^+$ events via $pp \to \phi_3 \phi_3 \to \tau^+ \tau^+ + 2 \cdot j_b$ ($j_b$=b-jet) at the 13 TeV LHC with an integrated luminosity of 300 fb$^{-1}$. We also consider the same-sign charged lepton signals in the LQ EFT framework at higher energy hadron colliders such as a 27 TeV HE-LHC and a 100 TeV FCC-hh.
Speaker: Shaouly Bar-Shalom (Physics Department Technion, Israel) -
201
Searches for high-mass resonances decaying into leptonic final states using the ATLAS detector
Many theories beyond the Standard Model predict new phenomena which decay to well isolated, high-pt leptons. Searches for new physics models with these signatures are performed using the ATLAS experiment at the LHC. The results reported here use 13 TeV pp collision data; prospects for HL-LHC will also be shown.
Speaker: Yosuke Takubo (High Energy Accelerator Research Organization (JP)) -
202
Searches for new resonances decaying to leptons, photons or jets with CMS
Various physics models beyond the standard model predict new particles that decay to leptons, photons or jets. This talk presents the status of CMS searches for new resonances decaying to a pair of leptons, photons or jets, as well as other states such lepton + missing transverse momentum. Searches for boosted dijet resonances recoiling against some high pT initial state radiation, as well searches using dijet angular distributions are also covered.
Speaker: Diego Beghin (Universite Libre de Bruxelles (BE)) -
4:00 PM
Coffee break
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203
Searches for non-resonant new phenomena in final states with leptons, photons and jets at CMS
Several new physics models such as those involving extra dimensions, leptoquarks, heavy neutrinos, W bosons with right handed couplings, excited fermions, seesaw models, etc. are expected to manifest themselves in non-resonant signatures with multiple leptons, photons or jets. This talk presents CMS searches for new non-resonant phenomena in the final states that involving leptons, photons and/or jets, focusing on the recent results obtained using data collected in the LHC run 2.
Speaker: Maximilian Heindl (Rutgers State Univ. of New Jersey (US)) -
204
High-$p_T$ Lepton Tails at the LHC and Flavour Physics
Large Hadron Collider (LHC) is delivering an unprecedented amount of data which enables ATLAS and CMS detectors to perform the most precise measurements of the Drell-Yan and mono-lepton high-pT tails. One the one hand, the LHC is a collider of five-quark flavors and several excellent methods of heavy flavor tagging in the final state have recently been developed, while on the other hand, a short distance new physics effects are enhanced at high-pT. Having this in mind, we explore the opportunities and challenges for studying heavy flavour physics in the high-pT tails in years to come.
Speaker: Admir Greljo -
205
Search for resonances in hadronic final states with the ATLAS detector
Many theories beyond the Standard Model predict new phenomena which decay to quarks. Light-quarks are of particular interest at the LHC since new phenomena produced in parton collisions are likely to produce final states with (at least) two partons. Omg the other hand, b- and top-quarks offer great potential to reduce the Standard Model background, although with significant challenges in reconstructing and identifying the decay products and modelling the remaining background. Recent searches in various hadronic final states performed with the ATLAS experiment at the LHC on the 13 TeV data will be presented, along with some prospects for HL-LHC.
Speaker: Aparajita Dattagupta (University of Oregon (US)) -
206
Search for heavy BSM particles coupling to third generation quarks at CMS
We present results from searches for new particles with enhanced couplings to third generation quarks, based on proton-proton collision data at a centre-of-mass energy of 13 TeV recorded by CMS. The signatures include single and pair production of vector-like quarks and heavy resonances decaying to third generation quarks. A wide range of final states, from multi-leptonic to entirely hadronic is covered. Jet substructure techniques are employed to identify highly-boosted heavy SM particles in their hadronic decay modes.
Speaker: Arne Christoph Reimers (Hamburg University (DE)) -
207
Searches for resonant di-boson production at CMS
Most recent CMS results on searches for heavy resonances decaying into gauge and Higgs bosons (VV, VH where V = W, Z) are presented. The results are based on the large dataset collected during Run 2 of the LHC at a centre-of-mass energy of 13 TeV. The analyses are optimised for high sensitivity over a large range in resonance mass. Jet substructure techniques are used to identify hadronic decays of highly-boosted W, Z, and H bosons.
Speaker: Dennis Roy (Rheinisch Westfaelische Tech. Hoch. (DE)) -
208
ATLAS Searches for Resonances Decaying to Boson Pairs
Many extensions to the Standard Model predicts new particles decaying into two bosons (W, Z, photon, or Higgs bosons) making these important signatures in the search for new physics. Searches for such diboson resonances have been performed in final states with different numbers of leptons, photons and jets and b-jets where new jet substructure techniques to disentangle the hadronic decay products in highly boosted configuration are being used. This talk summarizes recent ATLAS searches with LHC Run 2 data collected.
Speaker: Roland Jansky (Universite de Geneve (CH)) -
209
BSM Physics from Enlarged Gauge Symmetry: the 331 Model, a case of study.
We discuss the most relevant features of a BSM model with extra gauge symmetry, the so called 331 model. The gauge group is $SU(3)_c\times SU(3)_L \times U(1)_X$ implying the presence of extra gauge bosons, both charged and neutral, as well as extra/exotic fermions and an enlarged scalar sector. We present the relevant phenomenology of doubly-charged gauge bosons, which are a distinctive feature of a version of the 331 model, and discuss the role of BSM phenomenology as a tool for testing GUT (inspired) theories.
Speaker: Antonio Costantini (INFN Bologna) -
210
Exclusion Limits on Neutral, Mono and Doubly Charged Vector Bosons at LHC
In this work, we calculate limits on masses and couplings of neutral, mono and doubly-charged vector bosons predicted by a class of models based on the $SU(3)_{C} \times SU(3)_{L} \times U(1)_{X}$ symmetry group. These models offer an elegant explanation for the threefold replication of quark-lepton families. Different final states, including two, three and four leptons and leptons plus missing transverse energy are investigated. The processes cross-sections are estimated at the next to leading-order. A detector simulation is performed using the DELPHES package assuming the LHC center-of-mass energy of 13 TeV, with pile-up effects taken into account. Combining these calculations with the latest ATLAS results in different searches, we derive the most stringent bounds on masses and couplings for the predicted particles using LHC data. The results exclude the model vector bosons with masses within the range of 1 TeV to 4 TeV.
Speaker: Andre Asevedo Nepomuceno (Federal University of of Rio de Janeiro (BR))
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197
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6:45 PM
Beer Seminar and Tasting Campus Ledeganck - Auditorium 2
Campus Ledeganck - Auditorium 2
Ghent
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Cosmology: Common session on Cosmology, Astroparticle Physics and Gravitational Waves Campus Ledeganck - Aud. 2
Campus Ledeganck - Aud. 2
Ghent
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211
Relic neutrinos: local clustering and consequences for direct detection
The Cosmic Neutrino Background is a prediction of the standard cosmological model, but it has been never observed directly. Experiments with the aim of detecting relic CNB neutrinos are under development. For such experiments, the expected event rate depends on the local number density of relic neutrinos. Since massive neutrinos can be attracted by the gravitational potential of our galaxy and cluster locally, a local overdensity of relic neutrinos should exist at Earth. We report the status of our knowledge of neutrino clustering and the consequences for future direct detection experiments.
Speaker: Dr Stefano Gariazzo (IFIC-CSIC/University of Valencia) -
212
Probing pseudo-Dirac mass splittings by observing the high-energy astrophysical neutrinos from blazars
Pseudo-Dirac neutrinos are pairs of maximally-mixed Majorana neutrinos with tiny mass difference between the active and the sterile states in each pair. Their oscillation phenomenology is different from that of active neutrinos. Assuming blazars to be the source of astrophysical neutrinos, we construct all-sky maps of neutrino flavor compositions resulting from oscillations of pseudo-Dirac neutrinos originated from different redshifts. Using terrestrial measurements of neutrino flavor composition and the redshift distributions of blazars, we can constrain the mass splittings of pseudo-Dirac neutrinos.
Speaker: Dr tsugche Liu (LeCosPA, national taiwan university) -
213
Probing self-interacting dark matter through neutron stars
Compact stellar objects such as neutron stars (NS) are ideal places for capturing dark matter (DM) particles. We study the effect of self-interacting DM captured by the nearby NS that can reheat it to an appreciated surface temperature through absorbing the energy released due to DM annihilation. When DM-nucleon cross section $\sigma_{\chi n}$ is small enough, DM self-interaction will take over the capture process and make the number of captured DM particles increased as well as the DM annihilation rate. The corresponding NS surface temperature resulted from DM self-interaction is about hundreds of Kelvin and is potentially detectable by the future infrared telescopes. Such observations could act as the complementary probe on DM properties to the current DM direct searches.
Speaker: Dr Yen-Hsun Lin (Dept. of Physics, Nat'l Cheng Kung University, Taiwan) -
214
Constraints on Electromagnetic and Neutral Current Couplings of Dark Vector Boson to Standard Model Fermions by SN1987A
We study SN1987A constraints on the interactions between Standard Model fermions and dark vector boson. We consider a more general scenario that the dark boson mixes with Standard Model (SM) gauge bosons through both kinetic and mass mixing terms in the Lagrangian. Hence dark boson couples to SM fermions via vector and axial-vector couplings. Such couplings induce reactions $N+N\to N+N+Z_d$ inside the supernova (SN) neutrino-sphere and consequently affect the SN core-collapse dynamics. The emissivity resulting from the above production is calculated and the re-absorption process $N+N+Z_d\to N+N$, and decays $Z_d\to l^+l^-, \ \nu\bar{\nu}$ are also considered. It is shown that the axial-vector couplings between $Z_d$ and nucleons give dominant contributions to the emission and re-absorption processes of $Z_d$ compared to the contributions by vector couplings, assuming that the vector and axial-vector $Z_d-N-N$ couplings are comparable in magnitudes. The constraints on such couplings are obtained using SN1987A observations. We compare our constraints to those obtained from fixed target experiments, atomic parity violation, and the measurement on coherent elastic neutrino nucleus scattering.
Speaker: Prof. Guey-Lin Lin (Institute of Physics, National Chiao-Tung University, Taiwan) -
215
Vector-like leptonic dark matter, neutrino mass and collider signature
We study a class of models in which the Standard Model (SM) is augmented by vector-like leptons: one doublet and a singlet, which are odd under an unbroken discrete Z_2 symmetry. As a result, the neutral component of these additional vector-like leptons are stable and behave as dark matter. We study the phenomenological constraints on the model parameters and elucidate the parameter space for relic density, direct detection and collider signatures of dark matter. In such models, we further add a scalar triplet of hypercharge two and study the consequences. In particular, after electroweak symmetry breaking (EWSB), the triplet scalar gets an induced vacuum expectation value
(vev), which yield Majorana masses not only to the light neutrinos but also to vector-like leptonic doublet DM. Due to the Majorana mass of DM, the
Z-boson mediated elastic scattering with nucleon is forbidden and hence allowing the model to survive from stringent direct search bound. The DM without scalar triplet lives in a small singlet-doublet leptonic mixing region (sin θ ≤ 0.1) due to large contribution from singlet component and have small mass difference
(∆m ∼ 10 GeV) with charged companion, the NLSP (next to lightest stable particle), to aid co-annihilation for yielding correct relic density. Both these observations change to certain extent in presence of scalar triplet to aid
observability of hadronically quiet leptonic final states at LHC, while one may also confirm/rule-out the model through displaced vertex signal of NLSP, a characteristic signature of the model in relic density and direct search allowed parameter space.Speaker: Dr Narendra Sahu (Departtment of Physics, IIT Hyderbad, India) -
216
A feeble window on leptophilic dark matter
In this this talk, I will discus a leptophilic dark matter scenario involving feeble dark matter coupling to the Standard Model (SM) and compressed dark matter-mediator mass spectrum. I will consider a simplified model where the SM is extended with one Majorana fermion, the dark matter, and one charged scalar, the mediator, coupling to the SM leptons through a Yukawa interaction. I will first discuss the dependence of the dark matter relic abundance on the Yukawa coupling going continuously from freeze-in to freeze-out with an intermediate stage of conversion driven freeze-out. Focusing on the latter, I will then exploit the macroscopic decay length of the charged scalar to study the resulting long-lived-particle signatures at collider and to explore the experimental reach on the viable portion of the parameter space.
Speaker: Sam Junius (ULB/VUB) -
11:00 AM
Coffee break
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217
Bounds on Planck-scale deformation of CPT from lifetimes and interference
Deformed relativistic kinematics, expected to emerge in a flat-spacetime limit of quantum gravity, predicts the Planck-scale violation of discrete symmeries, in particular the CPT symmetry.
Momentum-dependent deformations of the action of CPT are derived from the kappa-deformed Poincare algebra.
In this approach, deformation of CPT symmetry leads to a subtle violation of
Lorentz symmetry.
This entails some small but measurable phenomenological consequences, as corrections to characteristics of time evolution: particle lifetimes or oscillations in two-particle states at high energy.
We argue that using current experimental precisions on the muon lifetime or quark flavour oscillations in systems of neutral mesons we can bound kappa>10^{14} GeV at LHC energy and move this limit to 10^{16} GeV at Future Circular Collider.Speaker: Prof. Wojciech Wislicki (National Centre for Nuclear Research) -
218
Towards Understanding the Origin of Cosmic-Ray Electrons
Precision results on cosmic-ray electrons are presented in the energy range from 0.5 GeV to 1.4 TeV based on 28.1 million electrons collected by the Alpha Magnetic Spectrometer on the International Space Station. In the entire energy range the electron and positron spectra have distinctly different magnitudes and energy dependences. The electron flux exhibits a significant excess starting from 41.2 GeV compared to the lower energy trends, but the nature of this excess is different from the positron flux excess above 25.2 GeV. Contrary to the positron flux, which has an exponential energy cutoff of 810 GeV, at the 5σ level the electron flux does not have an energy cutoff below 1.9 TeV. In the entire energy range the electron flux is well described by the sum of two power law components. The different behavior of the cosmic-ray electrons and positrons measured by AMS is clear evidence that most high energy electrons originate from different sources than high energy positrons.
Speaker: Cheng Zhang (Chinese Academy of Sciences (CN)) -
219
Where do AMS-02 anti-helium events come from?
In this talk, I will discuss consequences of the potential detection of anti-helium-3 and -4 events by AMS-02. After showing that spallation from primary hydrogen and helium nuclei onto the ISM cannot account for the measured fluxes, I will argue that dark matter annihilation or decay face similar difficulties in explaining these events. I will then entertain the possibility that these events originate from anti-matter-dominated regions in the form of anti-clouds or anti-stars. I will finally discuss constraints due to annihilation onto normal matter that apply on such scenario.
Speaker: Dr Vivian Poulin (LUPM, CNRS, France) -
220
Scrutinizing the evidence for dark matter in cosmic-ray antiprotons
Global fits of primary and secondary cosmic-ray (CR) fluxes measured by AMS-02
have great potential to study CR propagation models and search for exotic
sources of antimatter such as annihilating dark matter (DM). Previous studies
of AMS-02 antiprotons revealed a possible hint for a DM signal which, however,
could be affected by systematic uncertainties. To test the robustness of such a
DM signal, in this work we systematically study two important sources of
uncertainties: the antiproton production cross sections needed to calculate the
source spectra of secondary antiprotons and the potential correlations in the
experimental data, so far not provided by the AMS-02 collaboration. To
investigate the impact of cross-section uncertainties we perform global fits of
CR spectra including a covariance matrix determined from nuclear cross-section
measurements. As an alternative approach, we perform a joint fit to both the CR
and cross-section data. The two methods agree and show that cross-section
uncertainties have a small effect on the CR fits and on the significance of a
potential DM signal, which we find to be at the level of 3 sigma. Correlations
in the data can have a much larger impact. To illustrate this effect, we
determine possible benchmark models for the correlations in a data-driven
method. The inclusion of correlations strongly improves the constraints on the
propagation model and, furthermore, enhances the significance of the DM signal
up to above 5 sigma. Our analysis demonstrates the importance of providing the
covariance of the experimental data, which is needed to fully exploit their
potential.Speaker: Dr Jan Heisig (Université catholique de Louvain (UCL))
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211
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Detector R&D and Data Handling Campus Ledeganck - Aud. 4
Campus Ledeganck - Aud. 4
Ghent
Conveners: Nadia Pastrone (INFN), Niko Neufeld (CERN)-
221
A comprehensive real-time analysis model in Run 2 at the LHCb experiment
An evolved real-time data processing strategy is proposed for high-energy physics experiments, and its implementation at the LHCb experiment is presented. The reduced event model allows not only the signal candidate firing the trigger to be persisted, as previously available, but also an arbitrary set of other reconstructed or raw objects from the event. This allows for higher trigger rates for a given output data bandwidth, when compared to the traditional model of saving the full raw detector data for each trigger, whilst accommodating inclusive triggers and preserving data mining capabilities. The gains in physics reach and savings in computing resources already made possible by the model during Run 2 of the experiment are discussed.
Speaker: Biljana Mitreska (University of Manchester (GB)) -
222
A Novel Approach to Calorimeter-based Particle Identification at the Belle II Experiment using Scintillator Pulse Shape Discrimination
We present an innovative new approach to calorimeter-based particle identification at the Belle II experiment through the application of CsI(Tl) Pulse Shape Discrimination. By instrumenting the 8736 CsI(Tl) crystals in the Belle II calorimeter with new electronics that enable online CsI(Tl) waveform digitization and readout, during the first run of SuperKEKB collision data-taking in summer 2018 Belle II was the first B-Factory experiment to apply CsI(Tl) pulse shape discrimination to improve particle identification. With control samples of $e^\pm$, $\mu^\pm$, $\pi^\pm$, $K^\pm$ and $p/\bar{p}$ selected from collision data, we demonstrate through offline analysis of the waveform pulse shapes that hadronic interactions in the calorimeter crystals can be identified and distinguished from energy deposits produced by electromagnetic showers and minimum-ionizing particles. By applying pulse shape discrimination we are able to improve challenging and important areas of charged particle identification such as low momentum ($0.3 - 1$ GeV/c) $\mu$ vs $\pi$ separation. In addition with control samples of photon's and $K^0_\text{L}$'s isolated from Belle II collision data, we demonstrate that high efficiency $K^0_\text{L}$ identification with low photon fake-rates can be achieved through the unique information provided by pulse shape discrimination. The potential impact of pulse shape discrimination on improving planned physics analysis at Belle II will also be discussed.
Speaker: Savino Longo (University of Victoria) -
223
Application of Quantum Machine Learning to High Energy Physics Analysis at LHC using IBM Quantum Computer Simulators and IBM Quantum Computer Hardware
Using IBM Quantum Computer Simulators and Quantum Computer Hardware, we have successfully employed the Quantum Support Vector Machine Method (QSVM) for a ttH (H to two photons), Higgs coupling to top quarks analysis at the LHC.
We will present our experiences and results of a study on LHC high energy physics data analysis with IBM Quantum Computer Simulators and IBM Quantum Computer Hardware using IBM Qiskit. The work is in the context of a Qubit platform. Taking into account the limitation of a low number of qubits, the result expressed in a ROC curve is comparable with the results using a classical machine learning method. This study is applied to a Higgs-coupling-to–two-top-quarks (ttH) physics analysis, one of the flagship physics channels at the LHC. Here the ROC curve is defined as the Receiver Operating Characteristics curve in the plane of background rejection versus signal efficiency. At our current stage, with 5 qubits and 800 events, we have reached an AUC of 0.86, which is similar to the AUC of 0.87 from a classical machine learning method (BDT), where the AUC is the area under the ROC curve. By the time of the conference, we expect to have results with 20 qubits.
In addition, collaborating with IBM Research Zurich, we have finished training with machine learning on the IBM Quantum Computer Hardware with 100 training events, 100 test events, and 5 qubits, again for a ttH (H to two photons) analysis at the LHC. Because of hardware access time and timeout limitations, we finished only a few iterations. By the time of the conference, we expect to have performed the study on 20 qubits hardware with a large number of iterations.
The work is performed by an international and interdisciplinary collaboration with high energy physicists (Physics Department, University of Wisconsin), computational scientists (Computing Science Department, University of Wisconsin and IT Department, CERN Openlab), and quantum computing scientists (IBM Research Zurich).
This work pioneers a close collaboration of academic institutions with industrial corporations in a High Energy Physics analysis effort.Speaker: Chen Zhou (University of Wisconsin Madison (US)) -
224
Overview of the HL-LHC Upgrade for the CMS Level-1 Trigger
The High-Luminosity LHC will open an unprecedented window on the weak-scale nature of the universe, providing high-precision measurements of the standard model as well as searches for new physics beyond the standard model. Such precision measurements and searches require information-rich datasets with a statistical power that matches the high-luminosity provided by the Phase-2 upgrade of the LHC. Efficiently collecting those datasets will be a challenging task, given the harsh environment of 200 proton-proton interactions per LHC bunch crossing. For this purpose, CMS is designing an efficient data-processing hardware trigger (Level-1) that will include tracking information and high-granularity calorimeter information. The current conceptual system design is expected to take full advantage of advances in FPGA and link technologies over the coming years, providing a high-performance, low-latency computing platform for large throughput and sophisticated data correlation across diverse sources.
Speaker: Cecile Sarah Caillol (University of Wisconsin Madison (US)) -
225
The ATLAS Hardware Track Trigger design towards first prototypes
In the High Luminosity LHC, planned to start with Run4 in 2026, the ATLAS experiment will be equipped with the Hardware Track Trigger (HTT) system, a dedicated hardware system able to reconstruct tracks in the silicon detectors with short latency. This HTT will be composed of about 700 ATCA boards, based on new technologies available on the market, like high speed links and powerful FPGAs, as well as custom-designed Associative Memories ASIC (AM), which are an evolution of those used extensively in previous experiments and in the ATLAS Fast Tracker (FTK).
The HTT is designed to cope with the expected extreme high luminosity in the so called L0-only scenario, where HTT will operate at the L0 rate (1 MHz). It will provide good quality tracks to the software High-Level-Trigger (HLT), operating as coprocessor, reducing the HLT farm size by a factor of 10, by lightening the load of the software tracking.
All ATLAS upgrade projects are designed also for an evolved, so-called "L0/L1" architecture, where part of HTT is used in a low-latency mode (L1Track), providing tracks in regions of ATLAS at a rate of up to 4MHz, with a latency of a few micro-seconds. This second phase poses very stringent requirements on the latency budget and to the dataflow rates.
All the requirements and the specifications of this system have been assessed. The design of all the components has being reviewed and validated with preliminary simulation studies. After these validations are completed, the development of the first prototypes will start. In this paper we describe the status of the design review, showing challenges and assessed specifications, towards the preparation of the first slice tests with real prototypes.
Speaker: Francesca Pastore (Royal Holloway, University of London) -
226
Level 1 Muon Triggers for the CMS Experiment at the HL-LHC
The High Luminosity upgrade of the CERN Large Hadron Collider will deliver proton-proton collisions at 14 TeV with instantaneous luminosities up to 7.5*10^34 cm^-2 s^-1. The physics program of the Compact Muon Solenoid (CMS) Experiment strongly depends on the ability to identify muons at an early trigger stage, over a momentum range spanning from few GeV to the TeV scale. Several upgrades of the muon triggers are foreseen in order to retain such capabilities in view of the the High Luminosity LHC, including the acceptance on electroweak processes and the sensitivity to physics beyon the Standard Model. With this contribution, we review the current status of the design of highly efficient muon trigger, its architecture, based on state-of-the-art FPGAs and O(10) Gbps serial optical links, and the foreseen muon identification algorithms. We will discuss the local trigger primitives generation, depending on the new read-out of several detectors, their increased acceptance, and online muon reconstruction algorithms, both standalone and with the contribution of the silicon tracker at Level 1. The expected benefits for the HLLHC physics program are presented as well.
Speaker: Santiago Folgueras (Universidad de Oviedo (ES)) -
227
ATLAS Level-1 Endcap Muon Trigger for Run 3
The LHC is expected to increase its center-of-mass energy to 14 TeV and an instantaneous luminosity to 2.4x10^34 cm^-2s^-1 for Run 3 scheduled from 2021 to 2023. An upgrade of the ATLAS trigger system is required to cope with the high event rate. The level-1 Endcap Muon trigger system identifies muons with high transverse momentum by combining data from a fast muon trigger detector, TGC. In the ongoing phase-1 upgrade, new detectors called the New-Small-Wheel (NSW) and RPC-BIS78, will be installed in the inner station region for the endcap muon trigger. Excellent granularity track information from the NSW and RPC-BIS78 can be used as a part of the muon trigger logic to enhance the performance significantly. New electronics have been developed to handle data from both TGC and NSW, including the trigger processor board called Sector Logic (SL). The SL board has a modern FPGA to make use of Multi-Gigabit transceiver technology, which will be used to receive data from the NSW. The readout system for trigger data has also been re-designed, with the data transfer implemented with TCP/IP instead of a dedicated ASIC. This new system makes it possible to minimize the use of custom readout electronics and instead use commercial PCs and network switches to collect, format and send the data. This presentation describes the upgrades of the level-1 Endcap Muon trigger system as mentioned above, particularly emphasizing on the new algorithm in Sector Logic as well as the expected trigger performance.
Speaker: Tomoe Kishimoto (University of Tokyo (JP)) -
228
ATLAS Level-0 Endcap Muon Trigger for HL-LHC
The design for the Level-0 endcap muon trigger of the ATLAS experiment at High-Luminosity LHC (HL-LHC) and the status of the development are presented. HL-LHC is planned to start the operation in 2026 with an instantaneous luminosity of 7.5 x 10^34 cm^-2s^-1. In order to cope with the proton-proton collision rate higher than that of LHC, the trigger and readout system needs to be replaced. The new Level-0 endcap muon trigger system is required to reconstruct muon candidates with an improved momentum resolution to suppress the trigger rate with keeping the efficiency. That can be achieved by combining the signals from various subdetectors, thin gap chambers, resistive plate chambers,
micromesh gaseous detectors, and scintillator-steel hadronic calorimeters, to form more offline-like tracks. The combined muon track reconstruction was demonstrated with Monte-Carlo simulation
samples produced with the condition at HL-LHC. The efficiency was estimated to be greater than 90%, a few percents higher than the current system. The trigger rate was evaluated with proton-proton collision data taken with random trigger overlaid to account for a pileup of 200, which is expected at HL-LHC. The obtained value for momentum threshold of 20 GeV, primary threshold assumed for single muon trigger, is about 30 kHz, which constitutes only about 3% of the assumed total Level-0 trigger rate of 1 MHz. Hardware implementation is planned with ATCA blades. Each blade is designed to have a Virtex UltraScale+ FPGA with about hundred pairs of transceivers, which can be used to receive detector signals, and with huge memory resources suited for track reconstruction. The track
reconstruction is based on a pattern matching algorithm using the detector hits and the predefined lists of hits corresponding to tracks. A memory resource UltraRAM integrated into the FPGA is exploited to store the predefined lists of hits. Initial test with the evaluation kit VCU118 showed high efficiency and angular resolution better than the requirement with reasonable memory resources. The bit error ratio of the data transmission with GTY transceivers was evaluated with transfer rates up to 25 Gbps.
The power consumption of a hundred pairs of transmitter and receiver of GTY running with 10 Gbps, which is an average transfer rate assumed for the system, was evaluated to be about 30 W.Speaker: Haruka Asada (Nagoya University (JP)) -
11:00 AM
Coffee break
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229
Data Scouting and Data Parking with the CMS High level Trigger
The CMS experiments has devised two new strategies at the High Level trigger, to search for new physics in difficult corners of the phase space, or in large samples with B hadrons. The first strategy, called Data Scouting and already introduced in Run 1, allows to take data that would otherwise be rejected by the normal trigger filters. It is based on event-size reduction rather than event filtering and it is useful for instance to search for low mass resonances. The second strategy, called Data Parking, aims at overcoming the main limitation in the CMS data taking, which is the computing power involved in the prompt reconstruction. In 2018, a large amount of additional data, more than 1X10^10 events containing a pair of B hadrons, was collected by CMS and parked for a delayed offline reconstruction during the Long Shutdown 2. This dataset was triggered requiring a soft displaced muon originating from the decay of a B hadron, without applying any selection on the other B hadron, allowing an unbiased sample for competitive measurements on rare B-meson decays. The challenges of both methods are reviewed in this talk.
Speaker: Swagata Mukherjee (Rheinisch Westfaelische Tech. Hoch. (DE)) -
230
Fast Online Trigger using FPGA-based Event Classification for the COMET Phase-I
The COMET Phase-I experiment searches for a muon-to-electron conversion at a target sensitivity of $3\times10^{-15}$, which has never been observed. The event signature is the emission of a mono-energetic electron of 105 MeV from a muonic atom of aluminum. This electron is detected by a Cylindrical Drift Chamber (CDC) and a set of trigger counters (TC) in a 1 T solenoidal magnetic field.
A high intense muon beam is used to achieve our sensitivity goal. It leads to an unacceptable trigger rate of a few MHz. For stable data acquisition, a trigger system which can reduce it down to a few kHz is required. The total system latency of <5 $\mu$s is also required due to buffer sizes of readout electronics.
In order to fulfill these requirements, we are developing a fast online trigger system using a machine learning based event classification with Field Programmable Gate Arrays (FPGA). This system finds helical electron tracks from the aluminum target. It differs from finding tracks from a point source, and traditional methods such as Hough transform cannot be processed within the required latency. Therefore, we adopt a Gradient Boosted Decision Tree (GBDT) with using multivariate information from CDC; position, energy deposition, and timing. In this system, the trigger electronics collect the hit information from ~5000 wires of CDC and make a trigger decision every 100 ns. For the decisions, look-up-tables inside FPGA convert from it to GBDT outputs within a clock cycle.
From a simulation study, it is found that the classification can reject >90% of background events with a 99% of signal acceptance, which corresponds to the trigger rate of a few kHz in conjunction with the information of TC. The prototypes of trigger electronics were developed, and the total latency was measured to be 2.8 $\mu$s, which meets the requirement. Furthermore, we successfully took cosmic-ray data by using the trigger system installed in a CDC setup. We present these results and prospects.
Speaker: Mr Yu Nakazawa (Osaka University) -
231
Implementation of the ATLAS trigger within the multi-threaded AthenaMT framework
Athena is the software framework used in the ATLAS experiment throughout the data processing path, from the software trigger system through offline event reconstruction to physics analysis. The shift from high-power single-core CPUs to multi-core systems in the computing market means that the throughput capabilities of the framework have become limited by the available memory per process. For Run 2 of the Large Hadron Collider (LHC), ATLAS has exploited a multi-process forking approach with the copy-on-write mechanism to reduce memory use. To better match the increasing CPU core count and the, therefore, decreasing available memory per core, a multi-threaded framework, AthenaMT, has been designed and is now being implemented. The ATLAS High Level Trigger (HLT) system has been remodeled to fit the new framework and to rely on common solutions between online and offline software to a greater extent than in Run 2.
We present the implementation of the new HLT system within the AthenaMT framework, which will be used in ATLAS data-taking during Run 3 (2021-2023) of the LHC.Speaker: Cenk Yildiz (University of California Irvine (US)) -
232
Design and performance of the LHCb trigger and full real-time reconstruction in Run 2 of the LHC
The LHCb collaboration has redesigned its trigger to enable the full offline detector reconstruction to be performed in real time. Together with the real-time alignment and calibration of the detector, and a software infrastructure for persisting the high-level physics objects produced during real-time processing, this redesign enabled the widespread deployment of real-time analysis during Run 2. We will describe the design of the Run 2 trigger and real-time reconstruction, and present data-driven performance measurements for a representative sample of LHCb's physics programme.
Speaker: Michel De Cian (EPFL - Ecole Polytechnique Federale Lausanne (CH)) -
233
ATLAS LAr Calorimeter Performance in LHC Run-2
Liquid argon (LAr) sampling calorimeters are employed by ATLAS for all electromagnetic calorimetry in the pseudo-rapidity region |η| < 3.2, and for hadronic and forward calorimetry in the region from |η| = 1.5 to |η| = 4.9. In the first LHC run a total luminosity of 27 fb-1 has been collected at center-of-mass energies of 7-8 TeV. After detector consolidation during a long shutdown, Run-2 started in 2015 and about 150fb-1 of data at a center-of-mass energy of 13 TeV have been recorded.
In order to realize the level-1 acceptance rate of 100 kHz in Run-2 data taking, the number of read-out samples recorded and used for the energy and the time measurement has been modified from five to four while keeping the expected performance.
The well calibrated and highly granular LAr Calorimeter reached its design values both in energy measurement as well as in direction resolution.This contribution will give an overview of the detector operation, hardware improvements, changes in the monitoring and data quality procedures, to cope with increased pileup, as well as the achieved performance, including the calibration and stability of the electromagnetic scale, noise level, response uniformity and time resolution.
Speaker: Adriana Milic (University of Toronto (CA)) -
234
Conclusions from TrackML the HEP Tracking Machine Learning challenge
The HL-LHC will see ATLAS and CMS see proton bunch collisions reaching track multiplicity up to 10.000 charged tracks per event. Algorithms need to be developed to harness the increased combinatorial complexity. To engage the Computer Science community to contribute new ideas, we have organized a Tracking Machine Learning challenge (TrackML). Participants are provided events with 100k 3D points, and are asked to group the points into tracks; they are also given a 100GB training dataset including the ground truth. The challenge is run in two phases. The first "Accuracy" phase has run on Kaggle platform from May to August 2018; algorithms were judged judged only on a score related to the fraction of correctly assigned hits. The second "Throughput" phase ran Sep 2018 to March 2019 on Codalab, required code submission; algorithms were then ranked by combining accuracy and speed. The first phase has seen 653 participants, with top performers with innovative approaches (see arXiv:1904.06778). The second phase has recently finished and featured some astonishingly fast solutions. The talk will report on the lessons from the TrackML challenge and perspectives
Speaker: Laurent Roger Igor Basara (Universita degli Studi di Trento è INFN (IT))
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221
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Flavour Physics and CP Violation Campus Ledeganck - Aud. 5
Campus Ledeganck - Aud. 5
Ghent
Conveners: Admir Greljo, Angela Papa, Mitesh Patel (Imperial College (GB))-
235
Rank-One Flavor Violation and B-meson anomalies
We assume that the quark-flavor coefficients matrix of the semileptonic operators addressing the neutral-current B-meson anomalies has rank-one, i.e. it can be described by a single vector in quark-flavor space. By correlating the observed anomalies to other flavor and high-pT observables, we constrain its possible directions and we show that a large region of the parameter space of this framework will be explored by flavor data from the NA62, KOTO, LHCb and Belle II experiments.
Speaker: David Marzocca (INFN Trieste) -
236
Recent results from LHCb on charged-current decays of b-hadrons
b-hadron decays proceeding via charged-current interactions are excellent tools to study the CKM matrix, b-hadron properties, hadronic form-factors and Lepton Universality. The large branching fractions, coupled with excellent particle identification capability and accurate reconstruction of decay vertices, enable the LHCb experiment to perform high-precision measurements of many key quantities. In this contribution, recent results of charged-current interactions of b-hadrons at LHCb are presented.
Speaker: Anna Lupato (Universita e INFN, Padova (IT)) -
237
New results on the magnitudes of the CKM elements |V_{cb}| and |V_{ub}| from Belle
The magnitudes of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements, in combination with the angles of the Unitarity Triangle, are crucial for testing the standard model. We report a new determination of $|V_{cb}|$ based on $B \to D^* l^+ \nu$ decays in untagged events. Different parameterizations of the semileptonic form factor are used in the extraction of this CKM matrix element. Finally, we also cover the new Belle search for the purely leptonic decay $B \to \mu^+ \nu$, which will allow to determine $|V_{ub}|$. The analyses are based on the full data set recorded by the Belle detector at the KEKB $e^+ e^-$ collider containing 772 million $B\bar{B}$ pairs.
Speaker: Florian Urs Bernlochner (KIT - Karlsruhe Institute of Technology (DE)) -
238
Missing energy and electroweak penguin modes in early Belle II data
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is $8\times 10^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of data, a factor of 50 more than its predecessor. From February to July 2018, the machine has completed a commissioning run, achieved a peak luminosity of $5.5\times 10^{33}$ cm$^{-2}$s$^{-1}$, and Belle II has recorded a data sample of about 0.5 fb$^{-1}$. Main operation of SuperKEKB has started in March 2019.
In this presentation we show first results from studying missing energy signatures, such as leptonic and semileptonic B meson decays based on early Belle II data. We report first studies on re-measuring important standard candle processes, such as the abundant inclusive $B\to X\ell\nu$ and $B\to D^*\ell\nu$ decays. Furthermore, we will also present an overview of the semileptonic B decays that will be measured in the upcoming years at Belle II and discuss prospects for important B-anomalies like R(D) and R(D*), as well as other tests of lepton flavor universality. Early physics goals of the Belle II physics program are also to rediscover rare B decays. Especially radiative $b\to s \gamma$ decays can be measured on a small dataset and in the near future Belle II can provide independent tests of anomalies in $b\to s\ell \ell$ decays. Ultimately, the clean Belle II environment will allow to study modes with large missing energy such as $B\to K^\ast \nu \bar\nu$.
Speaker: William Sutcliffe (Karlsruhe Institute of Technology (KIT)) -
239
Study of $B\to D^{(*)} l \nu$ decays with a full angular analysis at $BABAR$
We present results on the first full 4-dimensional angular analysis of $B\to D^{(*)} l \nu$, using the $e^+e^-$ collision dataset collected by the $BABAR$ experiment at the $\Upsilon(4S)$ resonance. One $B$ meson from the $\Upsilon(4S)\to B\bar{B}$ decay is fully reconstructed in a hadronic decay mode which constrains the kinematics and provides a precise determination of the neutrino momentum vector. We extract the underlying hadronic form-factors employing the model-independent BGL approach and a value for the $CKM$ matrix element $|V_{cb}|$. Last, employing our measured BGL form-factors, we provide new predictions within the Standard Model, for observables related to the the semi-tauonic decay $B\to D^{(*)} \tau \nu$.
Speaker: Biplab Dey (CCNU) -
240
Precision predictions for B -> rho tau nu and B -> omega tau nu in the SM and beyond
We present new precision predictions for semitauonic decays involving rho and omega final state mesons. These decay channels offer an interesting orthogonal probe to study the existing B anomalies in semitauonic transitions and are accessible with the Belle II experiment. The predictions are based on combining existing light-cone sum-rule calculations for the form factors with measured experimental spectra from the BaBar and Belle collaborations. This allows us to extrapolate the light-lepton form factor predictions reliably to large values of the four-momentum transfer squared, q2, and in turn to derive precise predictions for R(rho) and R(omega), the ratio of the total decay rates of B -> rho l nu and B -> omega l nu for tau final states with respect to light leptons in the SM. In addition, we investigate the impact of all four-fermi operators on the semitauonic q2 spectra and these ratios.
Speaker: Markus Prim (KIT) -
10:55 AM
Coffee break
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241
Combining theory inputs for $B\to D^{(*)}\ell\nu$ and extracting $|V_{cb}|$
Recent theory results for the full set of hadronic matrix elements arising in $B\to D^{(*)}\ell\nu$ decays have triggered our interest. We investigate if and how various pieces of theory information on these hadronic matrix elements fit together. As a consequence, we obtain precise theory predictions for the full angular distribution of these decays in the SM and beyond. Finally, we challenge the experimental data available from the BaBar and Belle collaborations. We discuss the compatibility between our results for $|V_{cb}|$ and the inclusive determination.
Speaker: Marzia Bordone (Universitaet Zuerich) -
242
HAMMER: a tool for new physics searches in semileptonic decays at Belle II and LHCb
The search for new physics (NP) involving semileptonic $b$-hadron decays requires large, dedicated Monte Carlo data sets, in order to properly model acceptance and selection efficiencies. We present the Hammer reweighting tool, developed for and in conjunction with the LHCb and Belle II experiments, that makes use of an efficient event and histogram reweighting strategy, permitting computationally inexpensive exploration of NP effects in the fully differential phase space. The Hammer approach also permits study of the effects of different choices for hadronic form-factor parametrizations, crucial for the measurement of the CKM elements $|V_{cb}|$ and $|V_{ub}|$ In this talk we show various example applications of this tool, both for NP and CKM matrix studies.
Speaker: Stephan Duell (University of Bonn) -
243
The determination of |Vcb| from B->D(*)lnu
The precision determination of the CKM matrix element $|V_{cb}|$ from
semileptonic $B \to D^*$ and $B \to D$ decays provides an important input to test
the unitarity of the CKM matrix and search for new physics. In recent
analyses, higher values of $|V_{cb}|$ were extracted using (the so-called BGL)
form factor parametrization, which allows more freedom to describe the
experimental spectra. We develop a systematic approach to assess the
role of the truncation order of the form factor parametrization, and
study its impact on the extracted value of $|V_{cb}|$. In addition, we survey
the current status of $|V_{cb}|$ extractions and their compatibility with heavy
quark symmetry.Speaker: Florian Urs Bernlochner (KIT - Karlsruhe Institute of Technology (DE)) -
244
New predictions for Lambda_b -> Lambda_c semileptonic decays
The heavy quark effective theory makes model independent
predictions for semileptonic $\Lambda_b$ baryon decays in terms of a small
set of parameters. No subleading Isgur-Wise function occurs at order
$\Lambda_{QCD}/m_{c,b}$, and only two sub-subleading functions enter at order
$\left(\Lambda_{QCD}/m_{c}\right)^2$. These features allow us to fit the form factors and decay
rates calculated up to order $\left(\Lambda_{QCD}/m_{c}\right)^2$ to LHCb data and lattice QCD calculations. We derive a significantly more precise standard model
prediction than prior results for the ratio of the rates for
semi-tauonic vs. light-lepton decays. In addition, we investigate the
influence of all possible beyond standard model four-Fermi interactions
and present model independent predictions for them.Speaker: William Sutcliffe (Karlsruhe Institute of Technology (KIT)) -
245
Global fit to $b \to c \tau \nu$ transitions
We perform a general model-independent analysis of $b \to c \tau \bar{\nu}_\tau $ transitions, including measurements of $\mathcal{R}_D$, $\mathcal{R}_{D^*}$, their $q^2$ differential distributions, the recently measured longitudinal $D^*$ polarization $F_L^{D^*}$, and constraints on the $B_c \to \tau \bar{\nu}_\tau$ lifetime. A global fit to a general set of Wilson coefficients of an effective low-energy Hamiltonian is presented, assuming CP-invariance and linear electroweak symmetry breaking. The fitted solutions are interpreted in terms of hypothetical new-physics mediators. From the results obtained, we analyze the predictions for additional $b \to c$ observables such as the baryonic transition $\Lambda_b \to \Lambda_c \tau \bar{\nu}_\tau$, the ratio $\mathcal{R}_{J/\psi}$, the forward-backward asymmetry ${\cal A}_\text{FB}^{D^{(*)}}$, the $\tau$ polarization $\mathcal{P}_\tau^{D^{(*)}}$, and the longitudinal $D^*$ polarization $F_L^{D^*}$. At the $1\sigma$ level, one observes clear tensions among the current experimental inputs, independently of any new-physics hypothesis, which suggests that the reported anomalies could be partly driven by underestimated systematic uncertainties.
Speaker: Ana Peñuelas (IFIC)
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235
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Heavy Ion Physics ICC - Baeckeland 1
ICC - Baeckeland 1
Ghent
Conveners: Guilherme Milhano (LIP-Lisbon & CERN TH), Iwona Grabowska-Bold (AGH University of Science and Technology (PL)), Yen-Jie Lee (Massachusetts Institute of Technology), You Zhou (University of Copenhagen (DK))-
246
Measurement of $\Lambda_{\rm c}$ baryons and D$_{\rm s}^{+}$ mesons in Pb--Pb collisions with ALICE
The study of heavy-flavour (charm and beauty) production is important to understand the properties of the Quark-Gluon Plasma (QGP) formed in ultra-relativistic heavy-ion collisions, since heavy quarks are produced in the initial stages of the collisions and subsequently interact with the medium throughout its evolution.
In the QGP, strange quarks are expected to be abundantly produced and may recombine with charm quarks leading to an enhancement of the nuclear modification factor ($R_{\rm AA}$) of ${\rm D}_{\rm s}^{+}$ mesons over other charmed meson states at low and intermediate $p_{\rm T}$. The measurement of elliptic flow ($v_{2}$) of ${\rm D}_{\rm s}^{+}$ mesons is useful to determine the degree of thermalization of charm quarks in the collective expansion of the QGP. In addition, charm quarks could recombine with light di-quark states in the medium, which would lead to an enhancement of the production of the $\Lambda_{\rm c}/{\rm D}^{0}$ baryon-to-meson ratio as compared to that in pp collisions. Precise measurements of these particle species in Pb--Pb collisions, therefore, give a deeper insight into the hadronisation mechanisms that heavy quarks undergo in the strongly-interacting medium.
In this talk, we will discuss the latest results measured with ALICE for $\Lambda_{\rm c}$-baryon and ${\rm D}_{\rm s}^{+}$-meson production in Pb--Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV, using data from Run 2 of the LHC. The nuclear modification of $\Lambda_{\rm c}$ yield and the $\Lambda_{\rm c}$-to-${\rm D}^{0}$ ratio will be presented, along with the $R_{\rm AA}$ and $v_{2}$ of ${\rm D}_{\rm s}^{+}$ mesons.
Speaker: Lucas Anne Vermunt (Utrecht University (NL)) -
247
J/ψ production in hadron scattering: three-pomeron contribution
In this presentation we discuss the contribution of the three-pomeron configurations to quarkonia production in proton-proton collisions. This mechanism provides a natural explanation of the elevated multiplicities of the produced charged hadrons in the events with production of charmonia. The suggested mechanism gets dominant contribution from the region which can be theoretically described by CGC/Saturation approach, and numerically gives a substantial contribution to the J/ψ production. It is able to describe the experimentally observable shapes of the rapidity, momenta and multiplicity distributions. This implies that contribution of multipomeron (multigluon) mechanisms might be numerically substantial and should be analyzed in more detail.
Speaker: Marat Siddikov (Universidad Santa Maria) -
248
Quarkonia production in pPb and PbPb collisions at LHCb
We present LHCb results on quarkonia production in proton-lead collisions, using the data collected at 5.02 and 8.16 TeV nucleon-nucleon centre-of-mass energies, covering forward (pPb configuration) and backward (Pbp configuration) rapidities. Measurements include charmonia, where the prompt and from-b-decay components are disentangled, and bottomonia states. The large increase in size of the heavy flavour sample collected at 8.16 TeV with respect to the 5.02 TeV sample allows a remarkable improvement in the accuracy of the studies of nuclear matter effects. Coherent production of J/Psi in PbPb collisions are also presented.
The largely unknown parton distribution functions of nuclei and the similarities observed between high-multiplicity pp and pPb events compared to PbPb, often described by means of hydrodynamic models, are the main motivations for an extended pPb data taking program during LHC Run 3 and Run 4. The future increase in luminosity combined with LHCb's unique detector capabilities will allow new and precise measurements to be performed. Prospects will be presented on Drell-Yan production down to 5 GeV, DDbar correlations, and fully reconstructed b hadrons.
Speaker: Giacomo Graziani (INFN, Sezione di Firenze (IT)) -
249
Quarkonium production measured by the STAR experiment
Quark-gluon plasma and it's properties can be studied with quarkonium states used as a probe. Both $J/\psi$ and $\Upsilon$ states dissociate if a sufficiently high temperature is reached in the plasma. Since these quarkonium states have different binding energies, they are expected to dissociate at different temperatures, which is expected to lead to the so-called sequential suppression phenomenon.
There are also other effects, which contribute to the suppression such as nuclear absorption, shadowing or comover interactions. In addition, an enhancement of $J/\psi$ yield due to possible regeneration may contribute. Furthermore, by studying the quarkonium spectra and charged particle multiplicity dependence in p+p collisions important information can be gained on quarkonium production mechanism and it's relation with soft particle production.This presentation will include both $J/\psi$ and $\Upsilon$ production cross section measurements in p+p collisions at $\sqrt{s}=200\:\mathrm{GeV}$ and ${\sqrt{s}=500\:\mathrm{GeV}}$. Normalized quarkonium yield vs. normalized charged particle multiplicity will be shown. The nuclear modification factor in p+Au collisions at $\sqrt{s_{NN}}=200\:\mathrm{GeV}$, $R_{pA}$, will also be presented. Finally, the nuclear modification factors $R_{AA}$ in Au+Au collisions at $\sqrt{s_{NN}}=200\:\mathrm{GeV}$ will be shown. All the results will be compared to measurements by other experiments and model calculations.
Speaker: Dr Leszek Kosarzewski (Czech Technical University in Prague) -
250
Quarkonium measurements at forward rapidity with ALICE at the LHC
Heavy quarks are produced at the first instant of a nucleus-nucleus collision and therefore are an important tool to study the subsequent high energy-density medium formed in ultra-relativistic heavy-ion collisions. A series of experimental efforts for understanding the properties of the Quark-Gluon Plasma (QGP), a medium consisting of a deconfined state of quarks and gluons, are based on measuring the bound states of heavy quark-antiquark pairs known as quarkonia. However, the medium modification of heavy-flavour hadron production includes also the contribution of cold nuclear matter effects such as shadowing or nuclear break-up in addition to the QGP effects. Proton-nucleus collisions, where no QGP is expected, are used to measure cold nuclear matter effects on quarkonium production. Finally, quarkonium measurements in proton-proton collisions are used as reference for both heavy-ion and proton-ion collisions.
ALICE measurements of quarkonia at forward rapidity for various energies and colliding systems (pp, p--Pb, Pb--Pb and Xe--Xe) during the LHC Run-1 and Run-2 periods will be discussed. Recent ALICE results of quarkonium nuclear modification factor, elliptic flow and polarization using the 2018 Pb-Pb data sample will be specially highlighted. A comparison of the results among the LHC experiments and theoretical models will be also presented.
Speaker: Florian Damas (Centre National de la Recherche Scientifique (FR)) -
251
J/$\psi$ production measurements in pp, p-Pb and Pb-Pb collisions at mid-rapidity using the ALICE detector at LHC
J/$\psi$ production provides a particular sensitivity to the medium which can be produced in heavy-ion collisions at ultrarelativistic energies as delivered by the LHC. The vacuum production is modelled by a reference measured in proton-proton collisions and potential initial-state effects can be constrained using p--Pb collisions in the same collision-energy regime.
In this contribution J/$\psi$ production measured at mid-rapidity ($|y|<0.9$) with the ALICE detector down to zero transverse momentum is presented. Final results of the proton-proton collisions at $\sqrt{s} = 5.02$ TeV collected in 2017 are presented which serve also as a high-precision reference for the nuclear modification factors in p--Pb and Pb--Pb collisions at the corresponding centre-of-mass collision energy. The status of the analysis of the nuclear modification factor and the separation of the prompt and non-prompt components of J/$\psi$ production in p--Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 8.16$ TeV is shown. The status of the $p_{\rm T}$-differential J/$\psi$ cross section measurement in pp at $\sqrt{s} = 13$ TeV is also discussed. Available models are confronted with the data.
Speaker: Ingrid Mckibben Lofnes (University of Bergen (NO)) -
10:48 AM
Coffee break
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252
Heavy-Flavour production in fixed-target mode with LHCb
LHCb has the unique capability to study collisions of the LHC beams on fixed targets. Internal gas targets of helium, neon and argon have been used so far to collect samples corresponding to integrated luminosities up to 0.1 pb-1. An upgraded target, allowing a wider choice of target gas species and an increase in the gas density by up to two orders of magnitude, is planned to be installed for the LHC Run 3. Results and prospects on open and hidden charm production measurements will be presented. These measurements can provide crucial constraints on cold nuclear matter effects and nPDF at large x. In addition, production measurements of antiprotons and other light hadrons are of great interest for cosmic-ray physics.
Speaker: Felipe Andres Garcia Rosales (Centre National de la Recherche Scientifique (FR)) -
253
Constraining the gluon nuclear content with heavy-flavour production at the LHC
We report on our study showing that heavy-flavour production at the LHC can strongly improve our knowledge of the gluon content of the heavy nuclei. We have indeed observed that the nuclear effects encoded in both most recent global fits of nuclear parton densities at next-to-leading order (nCTEQ15 and EPPS16) gives a good account of the LHC proton-lead data. Thanks to a Bayesian-reweighting analysis for each particle data sample, we have shown that the existing data on $D^0$, prompt and nonprompt $J/\psi$, and $\Upsilon$ mesons clearly points, with a minimal statistical significance of 7$\sigma$, to a gluon distribution which is shadowed at small x in the lead. As such, the inclusion of such heavy-flavour data in a global fit is expected to drastically reduce the gluon-density uncertainty down to $x \simeq 7 \times 10^{-6}$, where no other data exist, while keeping an agreement with the other data of the global fits. We also address the issue of the factorisation-scale uncertainties which is particularly relevant for the charm(onium) sector.
References:
Gluon Shadowing in Heavy-Flavor Production at the LHC
By Aleksander Kusina, Jean-Philippe Lansberg, Ingo Schienbein, Hua-Sheng Shao.
arXiv:1712.07024 [hep-ph]. Phys.Rev.Lett. 121 (2018) no.5, 052004.Towards an automated tool to evaluate the impact of the nuclear modification of the gluon density on quarkonium, D and B meson production in proton–nucleus collisions
By Jean-Philippe Lansberg, Hua-Sheng Shao.
arXiv:1610.05382 [hep-ph]. Eur.Phys.J. C77 (2017) no.1, 1.Speaker: Jean-Philippe Lansberg (IPN Orsay, Paris Saclay U. / IN2P3-CNRS) -
254
Production of electroweak bosons in Pb+Pb, p+Pb and pp collisions with the ATLAS detector
Electroweak bosons produced in ultrarelativistic heavy-ion collisions serve as excellent probes of the collision geometry and centrality. Their production rates should be unaffected by initial-state effects. Due to the correlation between the kinematics of quarks from incoming nuclei and the rapidity of produced electroweak bosons, they also provide insight into nuclear modifications of parton distribution functions (PDFs). This talk presents the latest ATLAS results on massive electroweak boson production in Pb+Pb and $pp$ collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV using data collected by the ATLAS experiment in 2015. The yields of $W$ and $Z$ bosons produced per inelastic Pb+Pb collision are compared to cross-sections measured in $pp$ collisions and used to construct nuclear modification factors. A comparison of the measured yields and cross-sections to calculations obtained with various (nuclear) PDF sets is also presented. This talk also summarizes selected results on photon production in p+Pb collisions.
Speaker: Mariusz Przybycien (AGH Univesity of Science and Technology (PL)) -
255
Low-mass dielectron measurements Pb--Pb collisions with ALICE at the LHC
The production of low-mass dielectrons is the most promising tools for the understanding of the chiral symmetry restoration and of the thermodynamical properties of the Quark-Gluon Plasma (QGP) created in ultra-relativistic heavy-ion collisions. Since dielectrons are unaffected by strong final-state interactions and emitted during all stages of the collision, they carry information about the whole space-time evolution of the medium. The dielectron invariant mass allows for an approximate chronological view on this evolution. At low invariant mass ($m_{\rm ee}$ < 1.1 GeV/$c^2$), the dielectron spectrum is sensitive to in-medium modification of the spectral function of the rho meson and effects related to the chiral symmetry restoration. In the intermediate-mass region (1.1 < $m_{\rm ee}$ < 2.8 GeV/$c^2$), the dominant contribution of correlated pairs from semileptonic decays of charm and beauty hadrons is sensitive to in-medium effects on heavy-flavour production. Thermal radiation emitted by the system, both during the partonic and hadronic phase, contributes as well to the dielectron yield over a broad mass range and gives insight into the temperature of the medium. Finally, at very low pair transverse momenta initial photon annihilation processes, triggered by the coherent electromagnetic fields of the incoming nuclei, are expected to play a role in more peripheral collisions.
In this talk, we will present dielectron measurements with ALICE in Pb-Pb collisions at two energies, $\sqrt{s_{\rm NN}}$ = 2.76 and 5.02 TeV. The results will be compared to the expected dielectron yield from know hadronic sources and several predictions for the thermal radiation from the hadron gas and QGP phases. The study of virtual-photon production will be shown as well.
Speaker: Raphaelle Bailhache (Johann-Wolfgang-Goethe Univ. (DE)) -
256
$eA$ collisions at the LHeC and nuclear parton densities
The Large Hadron-electron Collider (LHeC) is a proposed upgrade of the LHC at CERN. It consists of an ERL providing electrons to collide with the HL-LHC, HE-LHC and the FCC-hh ion beams. It will achieve per nucleon centre-of-mass energies 0.8-2.2 TeV, respectively, and luminosities about $10^{33}$ cm$^{−2}$ s$^{−1}$ The LHeC and its possible successors will extend the kinematic plane in nuclear DIS by about four orders of magnitude towards smaller $x$ and larger $Q^2$ and therefore be the highest energy electron-ion colliders we can possibly build. DIS measurements in such configurations offer the unique opportunity to completely resolve the partonic content and dynamics inside nuclei, including observations of flavour dependent shadowing, non-linear parton interactions and similarly unresolved phenomena. Nuclear PDFs can be determined to very high precision and the relation to proton structure be established for each quark flavour and the gluon deep into an unknown range and independently of any proton PDF basis. This programme has the unique potential to completely change the view on nuclear structure and dynamics and resolve many phenomena at the heart of deconfinement and the Quark Gluon Plasma.
Speaker: Anna Stasto (Penn State)
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246
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Neutrino Physics ICC - Baeckeland 3
ICC - Baeckeland 3
Ghent
Conveners: Federico Sanchez (Universite de Geneve (CH)), Francesco Terranova (Universita & INFN, Milano-Bicocca (IT)), Yasaman Farzan (Institute for research in fundamental sciences (IPM).)-
257
The upgrade of the T2K Near Detector ND280
In view of the J-PARC program of upgrades of the beam intensity, the T2K collaboration is preparing towards an increase of the exposure aimed at establishing leptonic CP violation at 3 $\sigma$ level for a significant fraction of the possible $\delta_{CP}$ values. To reach this goal, an upgrade of the T2K near detector ND280 has been launched, with the aim of reducing the overall statistical and systematic uncertainties at the appropriate level of better than 4\%.
We have developed an innovative concept for this neutrino detection system, comprising the totally active Super-Fine-Grained-Detector (SuperFGD), two High Angle TPC (HA-TPC) and six TOF planes.
The SuperFGD, a highly segmented scintillator detector, acting as a fully active target for the neutrino interactions, is a novel device, (JINST 13 (2018) no.02, P02006; NIM A923 (2019) 134), with dimensions of ~2x1.8x0.6 m3 and a total mass of about 2 tons. It consists of about 2x106 small scintillator cubes each of 1 cm3. Each cube is covered by a chemical reflector. The signal readout from each cube is provided by wavelength shifting fibers inserted connected to micro-pixel avalanche photodiodes MPPCs. The total number of channels will be ~60,000. We have demonstrated that this detector, providing three 2D projections, has excellent PID, timing and tracking performance, including a $4 \pi$ angular acceptance, especially important for short proton and pion tracks.
The HA-TPC will be used for 3D track reconstruction, momentum measurement and particle identification. These TPC, with overall dimensions of 2x2x0.8 m3, will be equipped with 32 resistive Micromegas. The thin field cage (3 cm thickness, 4% rad. length) will be realized with laminated panels of Aramid and honeycomb covered with a kapton foil with copper strips. The 34x42 cm2 resistive bulk Micromegas will use a 500 kOhm/square DLC foil to spread the charge over the pad plane, each pad being appr. 1 cm2. The front-end cards, based on the AFTER chip, will be mounted on the back of the Micromegas and parallel to its plane.
The time-of-flight (TOF) detector will allow to reject events generated in the passive areas of the detector and improve particle identification. The TOF will consist of 6 planes with about 5 m2 surface area surrounding the SuperFGD and the TPCs. Each plane will be assembled with 2.2 m long cast plastic scintillator bars with light collected by arrays of large-area MPPCs from two ends. The time resolution at the bar centre is 150 ps.
In Summer 2018 we have tested prototypes of the SuperFGD, the resistive Micromegas and the TOF in a CERN PS test beam with excellent results.
We have recently completed the detailed TDR describing all the components of the ND280 Upgrade (arXiv:1901.03750). The project has been recently approved by CERN as part of the Neutrino Platform (NP07). In this talk we will report on the design of these detectors, their performance, the results of the test beam and the plan for the construction.Speaker: Etam Noah (Universite de Geneve (CH)) -
258
Recent T2K Neutrino Oscillation Results
T2K is a long baseline neutrino experiment producing a beam of muon neutrinos at the Japan Particle Accelerator Research Centre on the East coast of Japan and measuring their oscillated state 295 km away at the Super Kamiokande detector. Since 2016 T2K has doubled its data in both neutrino and antineutrino beam modes. Coupled with improvements in analysis techniques this has enabled the experiment to make world leading measurements of the PMNS oscillation parameters \Delta_m^{2}{32}, sin^2(\theta{23}) and the CP violating phase \delta_{CP}. In particular the CP conserving values of \delta_{CP} now appear to be disfavoured at the 95\% CL and there are regions of parameter space excluded at the 99.7\% CL. This talk will describe these results and the analysis improvements that have enabled them.
Speaker: Laura Kormos -
259
Latest three-flavor neutrino oscillation results from NOvA
The NOvA experiment is a long-baseline neutrino oscillation experiment that uses the upgraded NuMI beam from Fermilab to detect both electron appearance and muon disappearance. NOvA employs two functionally identical detectors: a Near Detector, located at Fermilab, and a Far Detector, located at Ash River, Minnesota over an 810 km baseline. NOvA's primary physics goals include precision measurements of neutrino oscillation parameters, such as $\theta_{23}$ and the atmospheric mass-squared splitting, along with probes of the mass hierarchy and the CP violating phase. This talk will present the latest NOvA measurements of the neutrino oscillation parameters using neutrino and antineutrino disappearance and appearance.
Speaker: Liudmila Kolupaeva -
260
Status of the DUNE Experiment
The Deep Underground Neutrino Experiment (DUNE) provides a rich science program with the focus on the neutrino oscillation physics and proton decay studies. The high-intensity wide-band neutrino beam will be produced at Fermilab and will be directed to the 40 kt Liquid Argon far detector at the Sanford Underground Research Facility (SURF), 1300 km from Fermilab. One of the most important goals of the experiment is to determine the neutrino mass ordering and the measurement of the CP violating phase. The underground location of the large DUNE far detector and its excellent energy and spatial resolution will allow also conducting non-accelerator physics programs predicted by GUT models, such as nucleon decay or n-nbar oscillations. Moreover, it will be sensitive to measure of the electron neutrino flux from a core-collapse supernova providing valuable information on the mechanism of a supernova. This ambitious project involves worldwide contribution and extensive prototyping and testing program to guarantee that all parts of the technology are fully understood and well tested. In 2018, the single-phase prototype took successfully data in the test beam and protoDUNE dual phase will start data taking with cosmics during summer this year. Both protoDUNEs will take date after LS2.
Speaker: Jaime Dawson (APC Paris) -
261
Testing the waters for the DUNE experiment
The huge size of the liquid argon based Deep Underground Neutrino Experiment (DUNE) has motivated efforts to validate its technology at its full scale, in the form of the ProtoDUNE setups at CERN. The 770-ton Single-Phase ProtoDUNE setup was constructed in about two years, and successfully took beam data in late 2018, just before the shutdown of the CERN accelerator complex. A grand total of over four million triggers were collected, for a variety of beam particle optimisations (protons, pions, positrons, kaons), and with beam energies in the 300 MeV to 7 GeV range as appropriate for the neutrino oscillation programme driving the DUNE design.
We will discuss the experience gained from constructing and operating the ProtoDUNE-SP detector, as well as the effort to overcome the specific problem of electric field distortions, introduced by the slow ion signal caused by the many cosmic-ray particles traversing the detector.
The collected data are invaluable to develop the reconstruction and calibration strategies for DUNE, and we will describe the status of the experiment and the energy calibration results obtained to date.Speaker: Frank Filthaut (Radboud University and Nikhef, Nijmegen (NL)) -
262
Status of ProtoDUNE Dual Phase
The Deep Underground Neutrino Experiment (DUNE) is a dual-site experiment for long baseline neutrino oscillation studies, and for neutrino astrophysics and nucleon decay searches. DUNE will comprise four 10 kton fiducial liquid argon time-projection-chamber (LAr TPC) modules placed at the Sanford Underground Research Facility (South Dakota, USA). One of these modules will profit form the dual phase (DP) technology where the charge is extracted, amplified, and detected in gaseous argon above the liquid surface allowing a fine readout pitch, a low energy threshold, and good pattern reconstruction of the events. To gain experience in building and operating such a large-scale DP LAr detector, a prototype is currently being assembled at the CERN Neutrino Platform. The ProtoDUNE-DP detector consists of a 6x6x6 m3 LAr TPC and commissioning will start in Summer 2019. An overview of the status and progress of ProtoDUNE-DP will be addressed in this talk.
Speaker: Clara Cuesta Soria (CIEMAT) -
11:00 AM
Coffee break
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263
Prospects for CP violation measurement with Hyper-Kamiokande
Three flavor neutrino mixing has been established by the continuous studies of neutrino oscillations since its discovery. Large mixing angles and small neutrino masses, in contrast to those in quark sector, imply new physics at ultra-high energy. In addition, as- yet unmeasured CP violation in neutrino sector is considered as a clue to investigate the origin of matter-antimatter asymmetry of the universe. Hyper-Kamiokande is a next generation large-scale water Cherenkov detector. With the baseline design, its fiducial volume is about an order of magnitude larger than Super-Kamiokande and the detector performance is significantly improved with newly developed photo-sensors. Combination of the Hyper-Kamiokande detector with the upgraded J-PARC neutrino beam will provide unprecedented high statistics of the neutrino and antineutrino signals to measure the CP violation and reveal a full picture of neutrino mixing with high precision. Prospects for the CP violation measurements by the Hyper-Kamiokande long baseline project will be presented.
Speaker: Benjamin Quilain -
264
Neutrino oscillation and CPT violation due to quantum decoherence at DUNE
We study the feasibility of observing deviations from the CPT symmetry owing to quantum decoherence and in the framework of the neutrino oscillations. Taking into account the open system approach, and considering non-diagonal decoherence matrices, we study all the cases in which CPT violation (CPTV) terms that could be arising in the neutrino oscillation probabilities. Considering the vacuum case, we find exact solutions for the CPT asymmetry function. Moreover, in order to show tangible results,to make predictions of this model for the future Long-Baseline experiment and based on the information from the $\nu_{\mu} \rightarrow \nu_{\mu}$ and $\bar{\nu}_{\mu}\rightarrow \bar{\nu}_{\mu} $ channels, we define an observable $\mathcal{R}$ and we put on trial all the CPTV cases using the DUNE experiment. We found values of the decoherence parameters with $5 \sigma$ of discrepancy to standard physics which are allowed by the current experimental limits suggesting hints for new physics by this model in the context of future experiments.
https://doi.org/10.1103/PhysRevD.99.075022
Speaker: Mr Félix Napoleón Díaz Desposorio (Pontificia Universidad Católica del Perú) -
265
A high precision narrow-band neutrino beam: the ENUBET project
The knowledge of initial flux, energy and flavor of current neutrino beams is currently the main limitation for a precise measurement of neutrino cross sections. The ENUBET ERC project (2016-2021) is studying a facility based on a narrow band neutrino beam capable of constraining the neutrino fluxes normalization through the monitoring of the associated charged leptons in an instrumented decay tunnel. In particular, the identification of large-angle positrons from $K_{e3}$ decays at single particle level can potentially reduce the $\nu_e$ flux uncertainty at the level of 1%. This setup would allow for an unprecedented measurement of the $\nu_e$ cross section at the GeV scale. Such an experimental input would be highly beneficial to reduce the budget of systematic uncertainties in the next long baseline oscillation projects (i.e HyperK-DUNE). Furthermore, in narrow-band beams, the transverse position of the neutrino interaction at the detector can be exploited to determine a priori with significant precision the neutrino energy spectrum without relying on the final state reconstruction.
This contribution will present the advances in the design and simulation of the hadronic beam line. Special emphasis will be given to a static focusing system of secondary mesons that, unlike the other studied horn-based solution, can be coupled to a slow extraction proton scheme. The consequent reduction of particle rates and pile-up effects makes the determination of the $\nu_\mu$ flux through a direct monitoring of muons after the hadron dump viable, and paves the way to a time-tagged neutrino beam. Time-coincidences among the lepton at the source and the neutrino at the detector would enable an unprecedented purity and the possibility to reconstruct the neutrino kinematics at source on an event by event basis. We will also present the performance of positron tagger prototypes tested at CERN beamlines, a full simulation of the positron reconstruction chain and the expected physics reach of ENUBET.
References:
F. Acerbi et al., Irradiation and performance of RGB-HD Silicon Photomultipliers for calorimetric applications, JINST 14 (2019) P02029.
F. Acerbi et al., A high precision neutrino beam for a new generation of short baseline experiments, arXiv:1901.04768.
F. Acerbi et al., The ENUBET project, CERN-SPSC-2018 / SPSC-I-248, 31/10/2018.
M. Pozzato et al., Status of the ENUBET project, J.Phys.Conf.Ser. 1056 (2018) no.1, 012047.
F. Pupilli et al., ENUBET: High Precision Neutrino Flux Measurements in Conventional Neutrino Beams, PoS NuFact2017 (2018) 087.
G. Ballerini et al, Testbeam performance of a shashlik calorimeter with fine-grained longitudinal segmentation, JINST 13 (2018) P01028.
A. Berra et al., Shashlik Calorimeters With Embedded SiPMs for Longitudinal Segmentation, IEEE Trans. Nucl. Sci. 64 (2017) no.4, 1056-1061.
A. Longhin et al., High precision measurements of neutrino fluxes with ENUBET, PoS NEUTEL2017 (2018) 050.
A. Berra et al., Longitudinally segmented shashlik calorimeters with SiPM readout, Nucl. Instrum. Meth. A845 (2017) 511-514.
F. Terranova et al., The ENUBET project: high precision neutrino flux measurements in conventional neutrino beams, PoS (EPS-HEP2017) 138.
A. Berra et al. Enabling precise measurements of flux in accelerator neutrino beams: the ENUBET project CERN-SPSC-2016-036 / SPSC-EOI-014, 05/10/2016.
A. Meregaglia et al., ENUBET: Enhanced NeUtrino BEams from kaon Tagging, JINST 11 (2016) no.12, C12040.Speaker: Giulia Brunetti (Universita e INFN, Padova (IT)) -
266
Neutrino CP Violation with the European Spallation Source neutrino Super Beam project
After measuring in 2012 a relatively large value of the neutrino mixing angle θ13, the door is now open to observe for the first time a possible CP violation in the leptonic sector. The measured value of θ13 also privileges the 2nd oscillation maximum for the discovery of CP violation instead of the usually used 1st oscillation maximum. The sensitivity at this 2nd oscillation maximum is about three times higher than for the 1st oscillation maximum inducing a lower influence of systematic errors. Going to the 2nd oscillation maximum necessitates a very intense neutrino beam with the appropriate energy. The world’s most intense pulsed spallation neutron source, the European Spallation Source, will have a proton linac with 5 MW power and 2 GeV energy. This linac, under construction, also has the potential to become the proton driver of the world’s most intense neutrino beam with very high potential to discover a neutrino CP violation. The physics performance of that neutrino Super Beam in conjunction with a megaton underground Water Cherenkov neutrino detector installed at a distance of about 500 km from ESS has been evaluated. In addition, the choice of such detector will extent the physics program to proton–decay, atmospheric neutrinos and astrophysics searches. The ESS proton linac upgrades, the accumulator ring needed for proton pulse compression, the target station optimization and the physics potential are described. In addition to neutrinos, this facility will also produce at the same time a copious number of muons which could be used by a muon collider. The ESS neutron facility will be fully ready by 2023 at which moment the upgrades for the neutrino facility could start.
This project is supported by the COST Action CA15139 "Combining forces for a novel European facility for neutrino-antineutrino symmetry-violation discovery" and the European Union’s Horizon 2020 research and innovation program under grant agreement No 777419.Speaker: Joakim Cederkall (INP, Krakow) -
267
GENUINE, MATTER-INDUCED AND INTERFERENCE COMPONENTS OF CPV, TRV, CPTV ASYMMETRIES FOR NEUTRINO OSCILLATIONS
This work represents the culmination of the solution for the historical problem
of the contamination of matter effects in the discrete CP, T, CPT asymmetries for neutrino propagation. The goal is accomplished in terms of a basis of three independent components: genuine CPT-even, matter-induced T-even, interference
CP-even. Independent of the theoretical framework for the dynamics of the active neutrino flavors,
A(CP)=A(CP,T)+A(CP,CPT), A(T)=A(T,CP)+A(T,CPT), A(CPT)=A(CPT,CP)+A(CPT,T)
for the three independent experimental asymmetries. For even a T-symmetric matter, A(T) is affected by matter due to quantum interference. For the effective
Hamiltonian written as the sum of free mass propagation plus the matter potential for electron-neutrinos, the three components have definite parities under the baseline L, the matter potential "a", the imaginary part sin(delta) of the PMNS mixing matrix and the hierarchy "h"=+-1 in the neutrino mass ordering: A(CP,T) is odd in L and sin(delta) plus even in a and h, A(CP,CPT) is even in L and
sin(delta) plus odd in a and h, A(T,CPT) is odd in all L, sin(delta), a and h.
The last interference component contains then terms like a.sin(delta).
The independent measurement of the three asymmetries could only be made in neutrino factories and atmospheric neutrinos. For present terrestrial accelerator sources of muon-neutrinos and antineutrinos, the two components of the appearance CPV asymmetry A(CP) can be disentangled, at a fixed baseline, by energy dependence. At the DUNE baseline, the higher energy region above the first oscillation node provides a dominant matter-induced A(CP,CPT) component. On the contrary, there is a "magic energy" E around the second oscillation maximum in which the fake A(CP,CPT) component has a first-rank zero whereas the genuine A(CP,T) component has a maximum (proportional to sin(delta)). With a modest energy resolution Delta E ~ 200 MeV an effective zero remains.Speaker: Prof. Jose Bernabeu (University of Valencia and IFIC)
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257
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Outreach, Education, and Diversity ICC - Baeckeland 2
ICC - Baeckeland 2
Ghent
Conveners: Arantza Oyanguren (IFIC - Valencia), Maria Catarina Espirito Santo (LIP)-
268
Future Challenges in Particle Physics Education and Outreach
The European Particle Physics Strategy Update 2020 discusses what Europe, taking into account the worldwide particle physics landscape, sees as the highest priorities for particle physics research in the coming decades. A wide spectrum of proposals and opportunities are examined to explore the basic building blocks of matter, the structure of time and space, and with it the origins of our Universe. Large-scale facilities will be required to deepen our understanding and to open new paths for future research. The duration of the planning, construction, commissioning, and operation stages of these facilities, regardless of which candidates are selected and prioritised, will span many decades.
The execution of these programmes thus relies heavily on support from key stakeholders and decision makers, including politicians, funding agencies and, underlying all, the public. Furthermore, the success of such large-scale projects depends heavily on the talents of a skilled, enthusiastic, and diverse new generation of physicists, engineers, and developers.
The International Particle Physics Outreach Group (IPPOG), a collaboration of 30 countries, major experiments in the field, and CERN, has built a world-wide education and outreach programme that is uniquely situated to address and inspire the current, and more importantly, the next generation of scientific talent, stakeholders, and the public. This talk will highlight the challenges particle physics education and outreach will need to address to ensure that these future projects are not only technically possible, but that they become global collaborative endeavours with the full support of society.
Speaker: Hans Peter Beck (Universitaet Bern (CH)) - 269
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268
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