• Satellite Session: Convener meeting 209(AB)



      Conveners: Un Ki Yang (Seoul National University (KR)) , Youngjoon Kwon (Yonsei University)
    • 6:00 PM
    • Astro-particle Physics and Cosmology: 1 104 (COEX, Seoul)


      COEX, Seoul

      Convener: Seong Chan Park (Yonsei University)
      • 1
        Ultralight Axion Dark Matter and Structure Formation

        The Ultra-Light Axion (ULA) is a dark matter candidate with mass 10^{-22} eV and
        de-Broglie wavelength of order kpc. Such an axion, also called the Fuzzy Dark Matter (FDM), thermalizes via the gravitational force and forms a Bose-Einstein condensate. The quantum pressure from FDM can significantly affect the structure formation in small scales, thus alleviating the so-called "small-scale crisis." We develop a new technique to discretize the quantum pressure and use N-body simulations to show the formation of the dark matter halo and its inner structure. We find a constant density solitonic core, which potentially solves the problems of small-scale crisis.
        We also investigate the effects of quantum pressure (QP) in cosmological simulations and find that QP leads to further suppression of the matter power spectrum at small scales. We then estimate the flux power spectrum of Lyman-alpha forest, and compare it to the data from BOSS and XQ-100 to set the lower bound on the FDM particle mass to 10^{−23} eV.

        Speaker: Kingman Cheung (National Tsing Hua University (TW))
      • 2
        Dark matter and early Universe

        Big-Bang nucleosynthesis (BBN) represents one of the earliest phenomena which can lead to observational constraints on the early Universe properties. Yet, it is well-known that many important mechanisms and phase transitions occurred before BBN. During this talk, I will discuss the possibility to gain insight about the primordial Universe through studies of dark matter in cosmology, astroparticle physics and colliders. For this purpose, we consider that dark matter is a thermal relic, and show that combining collider searches with dark matter observables can lead to strong constraints on the freeze-out period.

        Speaker: Alexandre Arbey (Lyon U. & CERN TH)
      • 3
        Unitarizing SIMP scenario with dark vector resonances

        We investigate a scenario of Strongly Interacting Massive Particles (SIMPs) where the thermal relic density of dark pion dark matter (DM) is determined by number changing 3→2 annihilations in a strongly interacting dark sector. In this scenario, including dark vector mesons in the hidden local symmetry scheme, we find that dark vector mesons unitarize the dark chiral perturbation theory (ChPT) efficiently and extend the range of validity of the leading order calculations. In QCD-like theories with SU(3)_L×SU(3)_R/SU(3)_V flavor symmetry, we show explicitly that the inclusion of these dark vector mesons in the 3→2 annihilation and 2→2 self-scattering of DM eliminates the tension between the Bullet Cluster bound and the relic density condition in a wide parameter space.

        Speaker: Soo-Min Choi (Chung-Ang University)
      • 4
        Dark matter in the early matter dominated Universe

        In the early Universe, there exists a matter-dominated era, that is driven by inflaton oscillation, curvaton, moduli or long-lived heavy particles. In this early matter domination, dark matter exists and show different behavior from the standard one during radiation domination, from the relics density to the density perturbation, constraints on the reheating temperature and baryogengesis. In this talk, I will present the recent developments.

        Speaker: Ki-Young Choi (Sungkyunkwan University (KR))
      • 5
        Relaxion: A Landscape Without Anthropics

        The relaxion mechanism provides a potentially elegant solution to the hierarchy problem without resorting to anthropic or other fine-tuning arguments. This mechanism introduces an axion-like field, dubbed the relaxion, whose expectation value determines the electroweak hierarchy as well as the QCD strong CP violating θ parameter. However, in the original model proposed by Graham, Kaplan and Rajendran (2015), the relaxion does not solve the strong CP problem, and in fact contributes to it, as the coupling of the relaxion to the Higgs field and the introduction of a linear potential for the relaxion produces large strong CP violation. We resolve this tension by considering inflation with a Hubble scale which is above the QCD scale but below the weak scale, and estimating the Hubble temperature dependence of the axion mass. The relaxion potential is thus very different during inflation than it is today. We find that provided the inflationary Hubble scale is between the weak scale and about 3 GeV, the relaxion resolves the hierarchy, strong CP, and dark matter problems in a way that is technically natural.

        Speaker: Chanda Prescod-Weinstein (University of Washington)
    • Beyond the Standard Model: 1 203 (COEX, Seoul)


      COEX, Seoul

      Convener: Archil Kobakhidze (The University of Sydney)
      • 6
        CP violation in B --> D** tau nu

        Current measurements of the branching fractions for b --> c tau nu processes yield results that are more than 4 standard deviations higher than the standard-model expectations. This motivates exploration of potential new physics in these decays, including searches for CP violation. A CP-violating asymmetry requires interference between amplitudes with different CP-violating and CP-conserving phases. We show that these conditions can be satisfied in B --> D** tau nu in the presence of new physics, and describe a new method for measuring the asymmetry at Belle II or LHCb.

        Speaker: Abi Soffer (Tel Aviv University (IL))
      • 7
        Tagging "Dark-Jet" at collider

        The phenomenology of dark matter would be complicated if dark matter is a composite particle as a hadron under a dark gauge group. Once a dark parton is produced at a high energy collider, it eventually evolves to a jet-like object and provides a collider signature depending on interactions with the Standard Model particles. For example, a finite lifetime of dark hadron would provide a displaced vertex. Thus by considering features in sub-detectors, one can identify a jet from a dark parton (“dark jet”) with analysis methods in conventional exotic searches. However if a lifetime of dark hadron is collider-negligible (too short to manifest a displaced vertex), dark jet would look like a normal QCD jet. In this study, inspired by one-prong jet tagging technologies which have been utilized in a quark- gluon jet discrimination, we propose that a combination of jet substructure variables become useful to tag a dark jet . We study features of several jet substructure variables with a dark jet. As an illustration, we apply jet substructure methods to O(100) GeV dark jet. Our result shows that by combining various jet substructure methods one could get a good discriminant power for a dark jet over QCD jets. We also discuss about a systematic uncertainty from the choice of parameters in a Monte Carlo simulation in estimating the tagging efficiency of a dark jet.

        Speaker: Mengchao Zhang (IBS-CTPU)
      • 8
        Spontaneous CP-violation in the Simplest Little Higgs Model

        We proposed the possiblity of spontaneous CP-violation in the simplest little Higgs (SLH) model. Based on the continuum effective field theory (CEFT) framework, we derived the properties of the scalar potential of this model. We carefully discussed the theoretical and experimental constraints on this model, and showed it is still alive. We also discussed the collider tests of CP-violation in the scalar sector in this model.

        Speaker: Ying-nan Mao (CFHEP,IHEP)
      • 9
        Exotic signals of heavy scalar bosons through vectorlike quarks

        Heavy vectorlike quarks (VLQs) in many new physics models are very attractive as they can play the key role in the model building and easily fit in with the Higgs measurement as well as the electroweak precision data. We study their loop level effects on the phenomenological signatures of a heavy scalar boson $S$. Under some conditions, loop induced decays of $S$ are significantly enhanced. First, the longitudinal polarization enhancement in the decay of $S \to WW/ZZ$ can happen at loop level, which is shown in a singlet extended standard model with VLQs. We find that the critical condition for the radiative enhancement is large mass differences among VLQs. Secondly, the heavy VLQs running in the loop open new decay channels of the charged Higgs bosons into $W\gamma$ and $WZ$. In a two Higgs doublet model with VLQs, the branching ratios can be as large as $10^{-3}$.

        Speaker: Jeonghyeon Song
      • 10
        Spectral Decomposition of Missing Transverse Energy at Hadron Colliders

        We propose a spectral decomposition to systematically extract information of dark matter at hadron colliders. The differential cross section of events with missing transverse energy (MET) can be expressed by a linear combination of basis functions. In the case of s-channel mediator models for dark matter particle production, basis functions are identified with the differential cross sections of subprocesses of virtual mediator and visible particle production while the coefficients of basis functions correspond to dark matter invariant mass distribution in the manner of the Källén-Lehmann spectral decomposition. For a given MET dataset and mediator model, we show that one can differentiate a certain dark matter–mediator interaction from another through spectral decomposition.

        Speaker: Tae Hyun Jung (Institute for Basic Science)
      • 11
        Jet substructure shedding light on heavy Majorana neutrinos at the LHC

        The existence of tiny neutrino masses and flavor mixings can be explained naturally in various seesaw models, many of which typically having additional Majorana type SM gauge singlet right handed neutrinos ($N$). If they are at around the electroweak scale and furnished with sizeable mixings with light active neutrinos, they can be produced at high energy colliders, such as the Large Hadron Collider (LHC). A characteristic signature would be same sign lepton pairs, violating lepton number, together with light jets -- $pp\to N\ell^{\pm}, \; N\to\ell^{\pm}W^{\mp}, \; W^{\mp}\to jj$. We propose a new search strategy utilising jet substructure techniques, observing that for a heavy right handed neutrino mass $M_N$ much above $M_{W^\pm}$, the two jets coming out of the boosted $W^\pm$ may be interpreted as a single fat-jet ($J$). Hence, the distinguishing signal topology will be $\ell^{\pm}\ell^{\pm} J$. Performing a comprehensive study of the different signal regions along with complete background analysis, in tandem with detector level simulations, we compute statistical significance limits. We find that heavy neutrinos can be explored effectively for mass ranges $300$ GeV $\leq M_N \leq 800$ GeV and different light-heavy neutrino mixing $|V_{\mu N}|^{2}$. At the 13 TeV LHC with 3000 $\mathrm{fb}^{-1}$ integrated luminosity one can competently explore mixing angles much below present LHC limits, and moreover exceed bounds from electroweak precision data.

        Speaker: Arindam Das (KIAS)
    • Dark Matter Detection: Axions 105 (COEX, Seoul)


      COEX, Seoul

      Convener: Jonghee Yoo (KAIST)
      • 12
        First Results from the ADMX G2 dark matter axion search

        The axion is a well-motivated dark matter candidate inspired by the
        Peccei-Quinn solution to the Strong-CP problem. After decades of
        work, the US DOE flagship axion dark matter search, ADMX G2, is the
        first experiment to be sensitive to dark matter axions from the
        plausible DFSZ coupling model, and has begun to search the
        theoretically-favored axion mass region 2-40 micro-eV. ADMX G2 could
        now discover dark matter at any time. I will report the first results
        from exploring the range around 2.7 micro-eV last year, discuss this
        year's operations and review the ADMX G2 plans to continue the search
        to cover the entire mass range.

        Speaker: Gray Rybka
      • 13
        CAPP’s axion data with mass range from 2.45 to 2.75 GHz

        CAPP’s flagship axion experiment, CULTASK, employs dilution refrigerators to lower the physical temperature of resonant cavities to less than 40 mK - the coldest ever for axion search. We prepared a complete set of the microwave axion detector (CAPP-PACE) equipped with an 8 T superconducting magnet with 12 cm inner bore in order to search for axions with mass around 2.5 GHz. The frequency tuning system installed in a split-design resonant cavity with a high Q-factor utilizes piezoelectric actuators with interchangeable sapphire and copper rods and performs flawlessly in searching a wide range of axion mass. The feeble signal ($~10^{-24}$ W) from the cavity is amplified and transmitted through the RF receiver chain, specially designed to minimize the noise temperature of the system employing an 1 K HEMT or a quantum-limited SQUID (Superconducting Quantum Interference Device) amplifier in order to raise the sensitivity and eventually speed up the axion search. I will present the results of CAPP’s first physics data runs in the axion mass range from 2.45 to 2.75 GHz and discuss our future plans and R&D projects.

        Speaker: Woohyun Chung (Center for Axion and Precision Physics Research, IBS)
      • 14
        Dark matter axion search experiments using 18T HTS magnet at CAPP/IBS in KAIST

        The presence of dark matter had profound consequences on the evolution of the Universe. The Standard Model does not accommodate a suitable dark matter candidate. Therefore, the existence of dark matter is a crucial phenomenological evidence for physics Beyond the Standard Model. The pressing goal of current and future dark matter experiments is to answer the question of whether dark matter interacts with normal matter other than gravity; i.e. if dark matter is detectable. Among the plethora of dark matter candidate particles, the Weakly Interacting Massive Particles (WIMPs) and the Axions are the most outstanding contender. In this talk, we will discuss about the dark matter axion search projects at the Center for Axions and Precision Physics Research at CAPP/IBS in KAIST, especially focused on the CAPP18T axion dark matter search experiment which utilizes a 18T High Temperature Superconducting solenoid magnet, resonant cavity, dilution refrigerator and linear amplifier system.

        Speaker: Byeonghun Min (Institute for Basic Science (IBS) )
      • 15

        The CAST-IBS/CAPP experiment is a joint effort between the CERN Axion Solar Telescope (CAST) collaboration [1] and the Center for Axion and Precision Physics Research (IBS/CAPP) [2], searching for cold dark matter axions.
        In this project, tunable rectangular cavities are inserted in the 9T CAST dipole magnet, an LHC prototype, at CERN.
        The traditional haloscope technique first suggested by Sikivie [3] is, for the first time, applied in a rectangular geometry configuration, rather than the common cylindrical geometry. The status and expected sensitivity of the experiment are presented.
        [1] CAST Collaboration, K. Zioutas et al., Phy. Rev. Lett. 94 (2005) 121301.
        [2] http://capp.ibs.re.kr/html/capp_en/
        [3] P. Sikivie, Phys. Rev. Lett. 51, 1415 (1983).

        Speaker: Lino Miceli (Institute for basic Science (KR))
      • 16
        MAGIS-100 at Fermilab

        The Matter-wave Atomic Gradiometer Interferometric Sensor (MAGIS) collaboration seeks to connect two quantum sensors across a long baseline. The phase in each device is compared across this baseline, enabling broad applications for basic science. The science is enabled by the ongoing advances in atomic clocks and atom interferometry.

        The experiment is sensitive to the distortion of the space-time between the sensors, and can be used to answer basic science questions in quantum mechanics, dark sector physics, and ‘mid-band’ gravitational wave detection. It will be able to detect well-motivated ultra-light dark matter candidates several orders of magnitude beyond current bounds, via time-varying signals. It can also probe hitherto unconstrained parts of parameter space in the search for new fundamental forces.

        This scheme is physically implemented in the configuration of MAGIS-100 by taking two atom interferometers and separating them across the baseline of the vertical 100-meter-deep NuMi access shaft at Fermilab.

        The Status and plans for the experiment will be presented.

        Speaker: Jonathon Coleman (University of Liverpool)
    • Detector: R&D for Present and Future Facilities: 1 103 (COEX, Seoul)


      COEX, Seoul

      Convener: Gobinda Majumder (Tata Inst. of Fundamental Research (IN))
      • 17
        Overview talk on detector performances at CMS

        The performance of CMS detector on early 2018 data will be presented. Special attention will be given to the performance of the recently upgraded components, and in particular to the silicon pixel detector and hadronic calorimeters.

        Speaker: Lucia Silvestris (Universita e INFN, Bari (IT))
      • 18
        Operational Experience and Performance with the ATLAS Pixel detector at the Large Hadron Collider

        The tracking performance of the ATLAS detector relies critically on its 4-layer Pixel Detector, that has undergone significant hardware and readout upgrades to meet the challenges imposed by the higher collision energy, pileup and luminosity that are being delivered by the Large Hadron Collider (LHC), with record breaking instantaneous luminosities of 2 x 10^34 cm-2 s-1 recently surpassed.
        The key status and performance metrics of the ATLAS Pixel Detector are summarised, and the operational experience and requirements to ensure optimum data quality and data taking efficiency will be described, with special emphasis to radiation damage experience.

        In particular, radiation damage effects will be showed and signs of degradation which are visible but which are not impacting yet the tracking performance (but will): dE/dX, occupancy reduction with integrated luminosity, under-depletion effects with IBL in 2016, effects of annealing that is not insignificant for the inner-most layers.
        In addition, the strategy to contain the readout bandwidth limitation will be discussed, required by the LHC over-performing.
        Numbers and strategy will also be discussed.

        Speaker: Marcello Bindi (Georg August Universitaet Goettingen (DE))
      • 19
        ATLAS Calorimeter system: Run-2 performance, Phase-1 and Phase-2 upgrades

        The ATLAS detector was designed and built to study proton-proton collisions produced at the LHC at centre-of-mass energies up to 14 TeV and instantaneous luminosities up to 10^{34} cm^{−2} s^{−1}. A liquid argon-lead sampling calorimeter (LAr) is employed as electromagnetic calorimeter and hadronic calorimeter, except in the barrel region, where a scintillator-steel sampling calorimeter (TileCal) is used as hadronic calorimeter.

        ATLAS recorded 87 fb^{-1} of data at a center-of-mass energy of 13 TeV between 2015 and 2017. In order to achieve the level-1 acceptance rate of 100 kHz, certain adjustments have been performed. The calorimetry system performed accordingly to its design values and have played a crucial role in the ATLAS physics programme. This contribution will give an overview of the detector operation, monitoring and data quality, as well as the achieved performance, including the calibration and stability of the energy scale, noise level, response uniformity and time resolution of the ATLAS calorimetry system.

        The upgrade projects of the ATLAS calorimeter system will also be presented.

        For Run-3, where luminosities around L ≃ 2 × 10^{34} cm^{−2} s^{−1} will be achieved, an upgrade of the LAr trigger readout is necessary to keep a high signal efficiency. The LAr Trigger Digitizer frontend system will digitize 34000 channels at 40 MHz with 12 bit precision after bipolar shaping. The backend LAr Digital Processing system will compute the energy and time of the signals. Results of ASIC developments including QA and radiation hardness evaluations, performances of the final prototypes and results of the system integration tests will be presented along with the overall system design.

        For the high luminosity phase of the LHC (HL-LHC), the luminosity will increase up to L ≃ 7.5 × 10^{34} cm^{−2} s^{−1} leading to an average pile-up up to 200 interactions per bunch crossing. The electronics of both calorimeters has to be upgraded to cope with longer latencies of up to 35 µs needed by the trigger system at such high pileup levels. The expected radiation doses will also exceed the qualification range of the current readout system.

        Low-noise, low-power, radiation-tolerant and high-bandwidth electronics components are being developed in 65 and 130 nm CMOS technologies for the LAr system. First prototypes of the front-end electronics components show good promise to match the stringent specifications. The off-detector electronics will make use of FPGAs connected through high-speed links to perform energy reconstruction, data reduction and buffering.
        For the Tile system, the photomultiplier signals will be digitized and transferred off-detector to the TileCal PreProcessors (TilePPr) for every bunch crossing, requiring a data bandwidth of 40 Tbps. The TilePPr will reconstruct, store and send the calorimeter signals to first level of trigger at a rate of 40 MHz. In parallel, the data samples will be stored in pipeline memories and the data of the events selected by the ATLAS central trigger system and transferred to the ATLAS global Data AcQuisition (DAQ) system for further processing.
        Results of tests of the first prototypes will be presented, along with design studies and simulations of the performance of the readout system.

        Speaker: Steffen Stärz (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 will measure minimum ionizing particles (MIPs) with a time resolution of ~30ps and hermetic coverage up to a pseudo-rapidity of |η|=3. 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 Diodes. 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 heavy flavor 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, including test beam results.

        Speaker: Andrea Davide Benaglia (Universita & INFN, Milano-Bicocca (IT))
      • 21
        Electron and photon identification with the ATLAS detector

        Excellent electron and photon identification capabilities are crucial for many aspects of the ATLAS
        physics program, from standard model measurements (including Higgs boson) to new physics searches.
        The identification of prompt photons and the rejection of backgrounds, mostly coming from photons
        from hadron decays, relies on the high granularity of the ATLAS calorimeter. Electron identification is
        based on a likelihood discrimination to separate isolated electron candidates from candidates originating
        from photon conversions, hadron misidentification and heavy flavor decays. Isolation variables are used
        as further handles to extract the signal. The measurement of the efficiencies of the identification and
        isolation cuts are performed using several high-statistics data samples, including Z->ee and J/psi->ee
        decays, radiative Z decays, and inclusive high energy photon samples. The results of these
        measurements, performed with pp collision data recorded at sqrt(s)=13 TeV during 2015-2017 and
        corresponding to an integrated luminosity of 80 fb-1, are presented. The impact of the pile-up, especially
        large in the second part of 2017 data taking, is discussed.

        Speaker: Nadezda Proklova (National Research Nuclear University MEPhI (RU))
      • 22
        CMS electron and photon performance at 13 TeV

        The Compact Muon Solenoid (CMS) detector is one of the two multi-purpose experiments at the Large Hadron Collider (LHC) and has a broad physics program. Many aspects of this program depend on our ability to trigger, reconstruction and identify events with final state electrons, positrons, and photons with the CMS detector with excellent efficiency and high resolution.

        In this talk we present the full process of electron and photon reconstruction in CMS, starting from tracker hits and energy deposits in the electromagnetic calorimeter, the method to achieve the ultimate precision in Run II energy measurements, the trigger and identification strategies (based both on cut based approach and on multivariate analysis) to discriminate prompt electrons and photons from background, and the methods to estimate the associated systematic uncertainties. Finally the performance on benchmark channels (such as H->gamma gamma and Z->ee) will be shown.

        Speaker: Francesco Micheli (Eidgenoessische Tech. Hochschule Zuerich (ETH))
      • 23
        Electron and photon energy measurement calibration with the ATLAS detector

        An accurate calibration of the energy measurement of electron and photon is needed for many ATLAS physics analyses. The calibration of the energy measurement is performed in-situ using a large statistics of Z->ee events. A pre-requisite of this calibration is a good understanding of the material in front of the calorimeter and of the inter-calibration of the different calorimeter layers. The Z->ee sample is also used to measure the energy resolution.
        The results obtained with the pp collisions data at sqrt(s)=13 TeV in 2015-2017 corresponding to an integrated luminosity of 80 fb-1 are presented as well as the corresponding uncertainties on the electron and photon energy scales.

        Speaker: Stefanie Morgenstern (CERN and Technische Universitaet Dresden (DE))
    • Heavy Ions: 1 205 (COEX, Seoul)


      COEX, Seoul

      Convener: Gian Michele Innocenti (Massachusetts Inst. of Technology (US))
      • 24
        Quarkonia production in pPb collisions with LHCb

        We present new results on quarkonia production in pPb collisions, using the data collected in 2016 at 8.16 TeV nucleon-nucleon centre-of-mass energy, in the unique forward region (pseudorapidity between 2 and 5) covered by the LHCb detector. Both forward and backward rapidities are covered thanks to the possibility of beam reversal. Measurements include the vector bottomonia states and the J/psi and psi(2S), where the prompt and from-b-decay components can be disentangled. The large increase in size of the heavy flavour sample, compared to 5 TeV sample collected in 2013, allows a remarkable improvement in the accuracy of the determination of nuclear modification factors.

        Speaker: Shanzhen Chen (Universita e INFN, Cagliari (IT))
      • 25
        Charmonium production in pp collisions with ALICE at the LHC

        In pp collisions at LHC energies, charmonium resonances are predominantly produced in hard scattering processes and a subsequent hadronization of the heavy quark pair into a bound state. The production process involves very different energy scales, with the initial quark pair being produced in a high-$Q^2$ process that allows for a perturbative treatment while the following formation of the bound state is a soft process. Moreover, recent observations have shown an enhancement of the $J/\psi$ production in high multiplicity pp collisions compared to minimum bias events at LHC energies. This suggests, that multi parton interactions (MPI) may also play a role in hard processes and not only, as initially thought, in soft particle production. The production of inclusive charmonia as a function of the event activity in pp collisions was studied by ALICE in different transverse momentum intervals at mid- and forward-rapidity. Measurements of the angular correlations between $J/\psi$ mesons and associated hadrons produced in the same event can shed light on the production of $J/\psi$ mesons as well as eventual global event correlations hypothesized to appear in high multiplicity events.

        In this talk, we will present recent ALICE results on $J/\psi$ production as a function of event multiplicity in pp collisions at $\sqrt{s}=$13 TeV. These results will be discussed in comparison to measurements at different collision energies and model calculations. Additionally, we will present the current status on $J/\psi$ - hadron angular correlations in pp collisions at $\sqrt{s}=$13 TeV at mid-rapidity.

        Speaker: Lucas Altenkamper (University of Bergen (NO))
      • 26
        Charmonium production in pPb and PbPb collisions at 5.02 TeV from CMS

        The nuclear modification factors of the ground and excited states of J/psi were measured via dimuon channels in pPb and PbPb collisions at 5.02 TeV. The analysis was performed as functions of collision centrality, rapidity, and transverse momentum. The results are discussed in the framework of the modified nuclear parton distribution function (for pPb) and the interaction of charmonia with dense partonic matter.

        Speaker: Kisoo Lee (Korea University (KR))
      • 27
        Open charm measurements in heavy ion collisions with the CMS detector

        Charm mesons are excellent probes for studying the properties of the hot and dense medium created in heavy-ion collisions. The measurement of their nuclear modification factor, elliptic and triangular flow can provide strong constraints for the mechanisms of in-medium energy loss. In this talk, the latest measurements of the $D^0$ in PbPb collisions at 5.02 TeV will be presented.

        Speaker: Hyunchul Kim (Chonnam National University (KR))
      • 28
        Open heavy-flavour production in Pb-Pb and Xe-Xe collisions measured with ALICE at the LHC

        Heavy quarks (charm and beauty) are effective probes of the properties of the Quark-Gluon Plasma (QGP) formed in high-energy heavy-ion collisions at the LHC. Produced mainly in initial hard parton scatterings on shorter time scales compared to the QGP formation time, they witness the full evolution of the system, interacting with the medium constituents and losing energy. The measurement of open-heavy-flavour hadron and jet production in heavy-ion collisions and the comparison (nuclear modification factor, $R_{\rm AA}$) with what expected from pp collisions give insight into the microscopic processes behind parton in-medium energy loss, in particular on its dependence on quark mass and colour charge, and on the interplay of elastic and radiative processes. At low transverse momentum the measurement of the relative abundances of different particle species, in particular non-strange D mesons, ${\rm D_{s}}^{+}$ mesons, and ${\Lambda_{c}}^{+}$ baryons, is fundamental to address the possible formation of hadrons via coalescence of charm quarks with medium quarks. The study of the heavy-flavour azimuthal anisotropy (elliptic flow, $v_2$) allows to constrain the path-length dependence of energy loss and, also thanks to the “Event-Shape Engineering” technique, the level of heavy-quark thermalisation and coupling to the system.

        Open-heavy-flavour production is measured with ALICE over a wide rapidity range: at mid-rapidity via the full reconstruction of hadronic decay channels of non-strange D mesons, ${\rm D_{s}}^{+}$ mesons, and ${\Lambda_{c}}^{+}$ baryons, and via the identification of electrons from charm and beauty semi-leptonic decays. At forward rapidity heavy-flavour hadron decay muons are detected. The properties of heavy-flavour jets are investigated with angular correlation of heavy-flavour hadron decay electrons with charged particles, as well as by directly reconstruct charm jets tagged by the presence of a D meson among its constituents.

        In this contribution new and most recent ALICE measurements of open heavy-flavour $R_{\rm AA}$ and $v_2$ in Pb-Pb and Xe-Xe collisions at the LHC will be presented. The comparison with measurements at different collision energies and with available theoretical calculations will be also discussed.

        Speaker: Andrea Rossi (Universita e INFN, Padova (IT))
    • Higgs Physics: 1 201 (COEX, Seoul)


      COEX, Seoul

      Conveners: Sarah Heim (Deutsches Elektronen-Synchrotron (DE)) , Jae Sik Lee (Chonnam National University)
      • 29
        The latest results of the measurement of the Higgs boson decaying to bottom quarks pair at CMS

        The latest results of the measurement of the Higgs boson decaying to bottom quark pair will be presented. The analysis is performed using data collected with the CMS experiment in 2016 and 2017 at the LHC from pp collisions at centre-of-mass energies of 13 TeV.

        Speaker: Pierluigi Bortignon (University of Florida (US))
      • 30
        Evidence for Higgs boson production in decays to two b-quarks using the ATLAS detector

        The analysis that studies VH process with H->bb decays is presented based on the 13 TeV pp collision data. A clear excess of the VH with H->bb process over the predicted background is shown providing evidence for such a process. In addition a search for VBF production in the same decay channel is presented.

        Speaker: Yuji Enari (University of Tokyo (JP))
      • 31
        Background study of HW production with the Higgs decaying to a b-quark pair

        We present next-to-leading order QCD predictions for $Wb\bar b+n$-jet ($n=0,1,2,3$) production at the Large Hadron Collider with $\sqrt{s}=13$ TeV. We work in the four-flavor number scheme with a non-vanishing bottom-quark mass and include all subprocesses at leading electroweak order as well as all heavy-fermion-loop effects. We show the impact of QCD corrections for total as well as differential cross sections and make an assessment of theoretical uncertainties of $Wb\bar b$ production viewed as an irreducible background to $H(\rightarrow b\bar b)W$ studies. For the calculations we have employed an upgraded version of the BlackHat library which can handle massive fermions in combination with SHERPA. Our results can be explored through publicly available n-tuple sets.

        Speaker: Fernando Febres Cordero (University of Freiburg)
      • 32
        Boosted Higgs decay in a pair of light jets

        We study the Higgs boson (h) decay to two light jets at the 14 TeV High-Luminosity-LHC (HL-LHC), where a light jet (j) represents any non-flavor tagged jet from the observational point of view. The decay mode h→gg is chosen as the benchmark since it is the dominant channel in the Standard Model (SM), but the bound obtained is also applicable to the light quarks (j=u,d,s). We estimate the achievable bounds on the decay branching fractions through the associated production Vh (V=W±,Z). Events of the Higgs boson decaying into heavy (tagged) or light (un-tagged) jets are correlatively analyzed. We find that with 3000 fb−1 data at the HL-LHC, we should expect approximately 1σ statistical significance on the SM Vh(gg) signal in this channel. This corresponds to a reachable upper bound BR(h→jj)≤4 BRSM(h→gg) at 95% confidence level. A consistency fit also leads to an upper bound BR(h→cc)<15 BRSM(h→cc) at 95% confidence level. The estimated bound may be further strengthened by adopting multiple variable analyses, or adding other production channels.

        Speaker: Zhuoni Qian (IBS)
      • 33
        Sensitive study of the Higgs-strange coupling at FCC-ee

        Precise measurment of the Higgs couplings is a central part of the energy-frontier physics program. Obtaining the small couplings to light states is particularly difficult. We describe a new technique for studying the Higgs coupling to the strange quark using H --> ssbar events at a 250 GeV e+e- collider. With this method, the sensitivity of the proposed FCC-ee collider is at a level of only a few times the standard-model expectation. This is a large improvement over previous proposals, yielding sensitivity to a variety of new-physics scenarios.

        Speaker: Abi Soffer (Tel Aviv University (IL))
    • Neutrino Physics: Solar/Atm/SN 202 (COEX, Seoul)


      COEX, Seoul

      Convener: Masashi Yokoyama
      • 34
        Results from Borexino on solar and geo-neutrinos

        Borexino is running at the “Laboratori del Gran Sasso” in Italy since 2007. Its technical distinctive feature is the unprecedented ultralow background of the inner scintillating core, which is the foundation for the outstanding achievements accumulated by this experiment.
        In the present talk, after recalling the main features of the detector, the impressive solar data gathered so far by Borexino will be summarized.
        Special emphasis will be given to the illustration of the recent release of the fluxes as stemming from the simultaneous real time spectroscopy of the neutrinos from the entire pp nuclear fusion chain in the Sun, opening with the remarkable 2.7% accuracy of the Be7 flux the era of precision measurements also in the realm of the sub-MeV solar neutrinos.
        Such results put Borexino in the unique situation of being the only detector able to perform solar neutrino spectroscopy over the entire solar spectrum; the counterpart of this peculiar status, in the flavor conversion interpretation of the solar neutrino data, is the capability of Borexino alone to perform the full validation across the solar energy range of the MSW-LMA paradigm.
        The talk will be concluded with an account of the Borexino accomplishments in the geo-neutrino field, marked by the detection of the geo-neutrino signal with a significance as high as 5.9 sigma.

        Speaker: Daniele Guffanti (GSSI)
      • 35
        Physics Potential of Super-K Gd

        The next stage of the highly successful Super-Kamiokande experiment is to load gadolinium (Gd) sulphate at 0.2% by mass. Gadolinium has a very large cross section for thermal neutron capture, which produces a cascade of gamma rays totalling 8 MeV. This is much easier to detect than the 2.2 MeV gamma ray from neutron capture on hydrogen that is currently used for neutron tagging. By tagging events which produce neutrons, background rates are radically reduced for some analyses.
        Super-K has published the best limits on the diffuse supernova neutrino background (DSNB, also called supernova relic neutrinos); neutron tagging with Gd will enable detection of the DSNB in 10 years from Gd loading.
        In the event of a core collapse supernova in our galaxy, neutron tagging with Gd will give new insight in to the dynamics of the neutrino burst, and a more accurate measurement of the direction to the supernova. Prior to a very close supernova (<1kpc), the late stages of stellar burning would be detected, giving even earlier supernova warning, and probing a never before observed stellar process.
        Super-K sets the best limits on proton decay - this will be improved by the addition of gadolinium as the majority of atmospheric neutrino induced backgrounds have one or more neutrons in the final state. Additionally hundreds or thousands of reactor neutrinos will be detected, and spallation induced backgrounds, which create dead-time for many analyses, will be reduced.
        The expected benefits of the addition of Gd are explored for these various physics analyses.

        Speakers: Charles Simpson (Oxford University and University of Tokyo, Kavli IPMU) , Charles Simpson (Oxford University and University of Toyko, Kavli IPMU)
      • 36
        The road to SuperK-Gd

        The Super-Kamiokande detector (SuperK) has been running since 1996. In addition to the discovery of neutrino oscillations which led to the Nobel Price in Physics in 2015, it has delivered many important results: the best proton lifetime and Diffuse Supernova Neutrino Background limits to cite two examples. With an extensive physics programme and a long and successful past, the SuperK collaboration has been working to go beyond these limits. Many of our studies could be improved if not only charged particles but also neutrons could be detected.

        Gadolinium has the largest cross-section for thermal neutron capture, emitting a gamma cascade of about 8 MeV. This cascade is detected with much higher efficiency than the capture on protons which just produces a single gamma of 2.2 MeV. Thus, by dissolving 0.2% of gadolinium (Gd) sulfate in mass in the otherwise ultra-pure SuperK water, 90% of the neutrons will be captured on Gd. To explore and fulfil this idea the EGADS project was funded in 2009. After the success of this project, the SuperK collaboration approved in 2015 the SuperK-Gd project. This year we will open the detector, refurbish and prepare it for a new era that will bring many new exciting results. In this talk, we will summarise the most important past milestones in the road towards SuperK-Gd as well as the work ahead of us to achieve its goals.

        Speaker: Lluis Marti
      • 37
        Oscillation Physics with Atmospheric Neutrinos at Hyper-Kamiokande

        After the initial observation of neutrino oscillations using atmospheric neutrinos, considerable progress has been made in the understanding of the mixing paradigm using long-baseline and reactor neutrinos. Despite these successes, there are several open questions remaining, including the ordering of the neutrino masses, the octant of the atmospheric mixing angle, and whether or not neutrino oscillations violate CP. Hyper-Kamiokande is next-generation water Cherenkov experiment that will observe long-baseline neutrinos from J-PARC as well as atmospheric neutrinos with its 187~kton fiducial volume. While its atmospheric sample is subject to considerable matter effects and provides sensitivity primarily to the neutrino mass hierarchy, its accelerator neutrino sample provides a clean measurement of the CP phase in the PMNS mixing framework, especially when the hierarchy is known.
        This talk will discuss Hyper-Kamiokande's oscillation sensitivity using atmospheric neutrinos and demonstrate the power of their combination with the beam sample to realize early resolutions to the open questions in oscillation physics.

        Speaker: Sandro Bravar (Universite de Geneve (CH))
      • 38
        Astrophysical Neutrinos at Hyper-Kamiokande

        Hyper-Kamiokande (Hyper-K) is a proposed next generation underground large water Cherenkov detector with 260 kton 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: Itaru Shimizu
      • 39
        Measuring Neutrino Oscillations with KM3NeT/ORCA

        ORCA is the low-energy detector of KM3NeT, the next generation underwater Cherenkov neutrino observatory in the Mediterranean Sea. With ORCA, the primary goal is to resolve the long-standing unsolved question of whether the neutrino mass ordering is normal or inverted, by measuring matter oscillation effects with atmospheric neutrinos. The ORCA design foresees a dense configuration of KM3NeT detection units, optimised for studying the interactions of neutrinos in seawater at energies < 100 GeV. The detector will be deployed at the French KM3NeT site, at 2500 m depth ~40 km offshore Toulon. The excellent optical properties of deep seawater will be exploited by the ORCA's multi-PMT optical modules to accurately reconstruct both cascade events (mostly induced by electron neutrinos) and track events (mostly from muon neutrinos). The construction of the detector has started. In this contribution we will report on the progress of the construction plan and will discuss the potentialities of the ORCA detector both in neutrino mass hierarchy studies and in obtaining new constraints on other key oscillation parameters.

        Speaker: Marco Circella (INFN Bari)
    • Quark and Lepton Flavor Physics: 1 102 (COEX, Seoul)


      COEX, Seoul

      Convener: Margarida Nesbitt Rebelo (Instituto Superior Tecnico (IST))
      • 40
        Radiative B decays at LHCb

        Radiative b-hadron decays are sensitive probes of New Physics through the study of branching fractions, CP asymmetries and measurements of the polarisation of the photon emitted in the decay. During Run-1 of the LHC, the LHCb experiment has collected large samples of radiative b-hadron decays. We present here the latest LHCb measurements, which help constrain the size of right-handed currents in extensions of the Standard Model.

        Speaker: Fedor Ratnikov (Yandex School of Data Analysis (RU))
      • 41
        Radiative B Decays at Belle

        The b→s gamma process is sensitive to new physics since the new heavy particles can enter in the loop and thus change the branching fractions, CP asymmetry or other kinetic variables. We present on measurement of the CP asymmetry and isospin asymmetry of B → Xs gamma and B → K* gamma, and also their difference of CP asymmetry between charged and neutral modes. The analyses are based on the full data set recorded by the Belle detector at the Υ(4S) resonance containing 772 million BBbar pairs from e+ e- collisions produced by the KEKB collider.

        Speaker: Akimasa Ishikawa (Tohoku University (JP))
      • 42
        Rare decays at CMS

        With the large integrated luminosity collected and the high efficiency of its di-muon triggers, the CMS experiment is a privileged test bench for rare decays involving heavy flavors. We report about the most recent measurements based on LHC Run 2 data, including decays of B and tau particles to muons and rare vector boson decays to heavy flavors.

        Speaker: Kai-Feng Chen (National Taiwan University (TW))
      • 43
        Towards a new paradigm for quark-lepton unification

        The quark and lepton mass patterns upset their naive unification. In this talk, a new approach to solve this problem is described. Model-independently, we find that a successful unification can be achieved. A mechanism is identified by which the large top quark mass renders its third-generation leptonic partner very light. This state is thus identified with the electron. We then provide a generic dynamical implementation of this mechanism, using tree-level exchanges of vector leptons to relate the quark and lepton flavor structures. In a supersymmetric context, this same mechanism splits the squark masses, and third generation squarks end up much lighter than the others. Finally, the implementation of this mechanism in SU(5) GUT permits to avoid introducing any flavor structure beyond the two minimal Yukawa couplings, ensuring the absence of unknown mixing matrices and their potentially large impact on FCNC.

        Speaker: Christopher Smith (LPSC)
      • 44
        Angular analyses at CMS

        Angular analyses of penguin B hadron decays such as B0->K ll constitute one of the main indirect probes of new physics at LHC, due to the clean theoretical predictions and precise experimental results that can be obtained. In this report we present the most recent results of the CMS experiment on this subject, including the measurement of the P1 and P5’ angular variables in B0->Kmumu decays and the angular analysis of the B+->K+mumu process.

        Speaker: Geng Chen (Peking University (CN))
    • Strong Interactions and Hadron Physics: 1 101 (COEX, Seoul)


      COEX, Seoul

      Convener: Ralf Seidl (RIKEN)
      • 45
        Measurement of Diffractive and Exclusive processes at CMS

        With excellent performance the Compact Muon Solenoid (CMS) experiment has made a number of key observations in the diffractive and exclusive processes and hence in probing the Standard model in a unique way. This presentation will cover recent results on the measurement of diffractive and exclusive processes using data recorded by CMS detector at the LHC.

        Speaker: Ruchi Chudasama (Bhabha Atomic Research Centre (IN))
      • 46
        Measurements of elastic pp interactions and exclusive production with the ATLAS detector

        The total pp cross section is a fundamental observable at the LHC. It can be derived from the measurement of the elastic cross section, using the optical theorem. Measurements of the elastic proton-proton cross section were performed at a center-of-mass energy of 8 TeV at various settings of the beam optics using the ALFA detector.
        The ALFA detector is also used to tag forward protons in order to enrich the exclusive diffractive production of pion pairs for first cross section measurements of this process at center-of-mass energies of 7 and 8 TeV.
        In the absence of forward proton tagging, exclusive processes can be distinguished in the central part of the ATLAS detector exploiting the absence of charged particles reconstructed in the inner tracking detector.
        If available, the talk will also cover the study of the exclusive pion production at 7 and 8 TeV, the total cross section and rho determination from elastic scattering, as well as an inclusive single diffractive study at 8 TeV.

        Speaker: Leszek Adamczyk (AGH University of Science and Technology (PL))
      • 47
        Exclusive rho(770) photoproduction at HERA

        Exclusive photoproduction of $\rho(770)$ vector mesons is studied using the H1 detector at HERA. A sample of about $700000$ decays $\rho\to\pi^{+}\pi^{-}$ was collected in the years 2006-2007, using the H1 fast track trigger. It corresponds to an integrated luminosity of $1.3$ pb$^{-1}$. The sample is used to study cross-sections as a function of the invariant mass $m_{\pi\pi}$ of the decay pions, the photon-proton collision energy $W$ and the momentum transfer at the proton vertex $t$. The phase-space restrictions are $0.5< m_{\pi\pi}<1.3$ GeV, $20< W< 80$ GeV and $\vert t\vert< 1.5$ GeV$^2$. Reactions where the proton stays intact are statistically separated from those where the proton dissociates to a low-mass hadronic system. The observed cross-section dependencies are parameterized using fits and are compared to expectations from phenomenological models.

        Speaker: Arthur Bolz (Ruprecht Karls Universitaet Heidelberg (DE))
      • 48
        Deeply Virtual Compton Scattering at Jefferson Lab

        Exclusive processes at high momentum transfer, such as Deeply Virtual Compton Scattering (DVCS) access the Generalized Parton Distributions (GPDs) of the nucleon. GPDs offer the exciting possibility of mapping the 3-D internal structure of protons and neutrons by providing a transverse image of the constituents as a function of their longitudinal momentum.

        A vigorous experimental program is currently pursued at Jefferson Lab (JLab) to study GPDs through DVCS and meson production. New results from Hall A will be shown and discussed. Special attention will be devoted to the applicability of the GPD formalism at the moderate values of momentum transfer. In addition, we will report on results for L/T separated pi0 electroproduction cross sections off the proton, the neutron and the deuteron. A large transverse response for both the proton and neutron cases is found, pointing to a possible dominance of higher-twist transversity GPD contributions. For the first time, a flavor decomposition of the u and d quark contributions to the cross section will be shown.

        We will conclude with a brief overview of additional DVCS experiments under analysis and planned with the future Upgrade of JLab to 12 GeV.

        Speaker: Carlos MUNOZ CAMACHO (CNRS)
      • 49
        The CMS-TOTEM Precision Proton Spectrometer and first physics results

        The CT-PPS (CMS-TOTEM Precision Proton Spectrometer) detector system consists of silicon tracking stations as well as timing detectors to measure both the position and direction of protons and their time-of-flight with high precision. They are located at around 200 m from the interaction point in the very forward region on both sides of the CMS experiment. CT-PPS is built to study Central Exclusive Production (CEP) in proton-proton collisions at LHC, including photon-photon production of W and Z boson pairs, high-mass diphoton and dilepton production, high-$p_T$ jet production, as well as searches for anomalous couplings and new resonances.

        The CT-PPS detector has taken data at high luminosity while fully integrated to the CMS data acquisition system. The total data collected correspond to around 55 ${\rm fb}^{-1}$. In this presentation the CT-PPS operation, commissioning and performance are discussed.

        The measurements of dilepton and diphoton production in photon-photon fusion with CT-PPS are presented. For the first time, exclusive dilepton production at high masses have been observed in the CMS detector while one or two outgoing protons are measured in CT-PPS using around 10 ${\rm fb}^{-1}$ of data accumulated in 2016 during high-luminosity LHC operation. These first results show a good understanding, calibration and alignment of the new CT-PPS detectors. Preliminary results concerning the search for high-mass exclusive diphoton production are presented.

        Speaker: Jonathan Jason Hollar (LIP Laboratorio de Instrumentacao e Fisica Experimental de Part)
    • Top Quark and Electroweak Physics: 1 209 (COEX, Seoul)


      COEX, Seoul

      Convener: Tae Jeong Kim (Hanyang University (KR))
      • 50
        Recent ttbar (inclusive and differential) cross sections results in CMS

        Latest results on inclusive top quark pair production cross sections are presented using proton-proton collision data collected by CMS at different centre-of-mass energies, including 5 TeV. Final states with at least one charged lepton and one b-jet are explored to measure inclusive production cross sections. The sensitivity of some these measurements to PDFs and extraction of standard model parameters is also described. Moreover, first ttbar cross sections results in proton-lead collisions are discussed. Differential top quark pair production cross sections are discussed with respect to kinematic variables in final states with at least one lepton. Constraints placed on the EFT operator OtG are discussed as well as the measurement of ttbar asymmetries in the top quark-antiquark system.

        Speakers: Douglas John Paul Burns (University of Bristol (GB)) , Douglas John Paul Burns (University of Bristol (GB))
      • 51
        Top quark production cross-section measurements with the ATLAS detector

        Measurements of the inclusive and differential top-quark pair production cross sections in proton-proton collisions with the ATLAS detector at the Large Hadron Collider at center-of-mass energies of 8 TeV and 13 TeV 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 tops, probe our understanding of top-quark pair production in the TeV regime.

        Speaker: Peter Berta (Johannes Gutenberg Universitaet Mainz (DE))
      • 52
        Top physics at LHCb

        LHCb, while purpose built for b-physics, also functions as a general purpose forward detector, covering the pseudo-rapidity range 2.0 to 5.0. Measurements of top production in the LHCb acceptance have particular sensitivity to high values of Bjorken-x, and offer complementary PDF constraints to measurements at the central detectors. In addition, the higher contribution from quark-initiated production to top pair production in the forward region leads to a larger expected charge asymmetry at LHCb than at the other experiments. The first Run 2 measurement of top pair production at LHCb at 13 TeV will be presented, along with previous Run 1 measurements in final states accessible to both single top and top pair production.

        Speaker: Carlos Vazquez Sierra (Nikhef National institute for subatomic physics (NL))
      • 53
        Single top quark production in CMS

        Recent results on single top quark production are presented, performed using CMS data collected at different centre-of-mass energies. The single top quark analyses investigate separately the production of top quarks via t-channel exchange, in association with a W boson (tW) or via the s-channel. Differential measurements of t-channel production cross sections are also presented.

        Speaker: Matthias Komm (Imperial College (GB))
      • 54
        Single Top quark production and properties measurements using the ATLAS detector

        Measurements of single top-quark production in proton-proton collisions and of angular correlations in single top-quark events are presented based on the 8 TeV and 13 TeV ATLAS datasets. For the production of single top quarks in the t-channel and the tW-channel, measurements of inclusive and differential cross-sections are included. Evidence for s-channel production using 8 TeV data and the measurement of single top quark production in association with a Z boson at 13 TeV are also presented. All measurements are compared to state-of-the-art theoretical calculations. Differential cross-sections are measured as a function of angular variables that are sensitive to anomalous contributions to the Wtb vertex and the top quark polarization.

        Speaker: Marcel Vreeswijk (Nikhef National institute for subatomic physics (NL))
    • 10:30 AM
      Coffee break
    • Astro-particle Physics and Cosmology: 2 104 (COEX, Seoul)


      COEX, Seoul

      Convener: Carsten Rott (Sungkyunkwan University)
      • 55
        In between the Observation Runs 2 and 3, a status report on the Advanced LIGO and Advanced Virgo gravitational-wave detectors

        Following a fruitful Observation Run 2 (O2, November 2016 - August 2017) marked by the first three-detector observation of a binary black hole merger and the first ever detection of a binary neutron merger followed by the discovery of the optical counterpart of the gravitational-wave signal, the LIGO and Virgo giant interferometers started a new upgrade phase with a twofold goal: to improve the sensitivity and the duty cycle of the three instruments before starting the Observation Run 3 (O3) next fall, which should last about a year.

        After a brief review of the O2 data taking period and a summary of the main results achieved, including the successes of multi-messenger astronomy, we will describe the current upgrade campaign, review the performance achieved to date and conclude by presenting some prospects for O3.

        Speaker: Dr Nicolas Arnaud (LAL (CNRS/IN2P3 and Université Paris-Sud))
      • 56
        Probing the Reheating Temperature with a Gravitational Waves: with application to Gauss-Bonnet Inflation

        In this work, inflationary models with Gauss-Bonnet term is classified into two categories based on their prediction for the tensor spectral index ($n_T$). We showed that the energy spectrum of the primordial gravitational waves (GWs) induced by a group of models that predict blue-tilted tensor spectrum ($n_T>0$) can be probed by the future space-based laser interferometer experiment such as DECIGO in frequency ranges of $0.1-10$ Hz. If the signals of primordial GW background from our models is detected, it would determine the lower bound of the reheating temperature, which is $T_\text{re}\geq10^{-6}$ in our case. Our further analyses on reheating parameters imply that the effect of GB term is significant not only during inflation but also during reheating regardless of the process is instantaneous or lasted for a certain number of $e$-folds until it completes.

        Speaker: Gansukh Tumurtushaa (Institute for Basic Science)
      • 57
        ​Search for Rotational Cross-Correlations in Emergent Space-Time with the Holometer

        ​We present a new phenomenology for the Fermilab Holometer, a pair of 39m-long, co-located but independent high-power Michelson interferometers. The differential position signals are cross-correlated over a broad frequency band exceeding the inverse light crossing time, attaining sensitivity to both timelike and spacelike correlations across the physical system. The second-generation experiment employs a unique bent-arm configuration to search for rotational correlations associated with the emergence of flat space-time and local inertial frames from a quantum system. A Planck density spectrum in dimensionless strain units is shown to be consistent with causal diamonds of 4-position whose degrees of freedom scale with the holographic information content of black hole event horizons.

        A Lorentz invariant framework is constructed to interpret data. Nonlocal entanglements among states in relational space-time are statistically modeled as antisymmetric cross-covariances on past and future light cones between world lines of Planck bandwidth in proper time, motivating a distinctive signature: an imaginary broad-band cross-spectrum that is acausal in standard physics, with a frequency response derived from the optical layout and its causal structure.

        Speaker: Dr Ohkyung Kwon (KAIST)
      • 58
        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: Masashi Yokoyama (University of Tokyo (JP))
    • Beyond the Standard Model: 2 203 (COEX, Seoul)


      COEX, Seoul

      Convener: Jeonghyeon Song (Konkuk U.)
      • 59
        The unexplored landscape of top-partner decays

        We discuss the LHC sensitivity to top partner production in a model where the Standard Model (SM) is extended by an SU(2) singlet top partner and a SM gauge singlet scalar.
        Unlike most searches for top partners which are concerned with three conventional decay modes, Wb, tZ and tH, the decay pattern of the top partner in this model can be significantly altered with new decay modes, gluon + top, photon + top and singlet scalar + top.
        We present a new approach to search for a pair-produced top partner that decays to a top quark and a gluon (photon). We give an overview of the various production and decay channels of the top partner and project the sensitivity of the high luminosity LHC.

        Speaker: K.C. Kong (University of Kansas)
      • 60
        The MoEDAL Experiment at the LHC - a New Light on the High Energy Frontier

        MoEDAL, is a pioneering LHC experiment designed to search for anomalously ionizing messengers of new physics such as magnetic monopoles or massive (pseudo-)stable charged particles, that are predicted to existing a plethora of models beyond the Standard Model. It started data taking at the LHC at a centre-of-mass energy of 13 TeV, in 2015. Its ground breaking physics program defines a number of scenarios that yield potentially revolutionary insights into such foundational questions as: are there extra dimensions or new symmetries; what is the mechanism for the generation of mass; does magnetic charge exist; and what is the nature of dark matter. MoEDAL purpose is to meet such far-reaching challenges at the frontier of the field. We will present the results from the MoEDAL detector on Magnetic Monopole and highly ionizing electrically charged particle production that are the world’s best. In conclusion, progress on the installation of MoEDAL’s MAPP (MoEDAL Apparatus for the detection of Penetrating Particles) sub-detector prototype will be very briefly be discussed.

        Speaker: James Pinfold (University of Alberta (CA))
      • 61
        Loop Induced Single Top Partner Production and Decay at the LHC

        Most searches for top partners, T, are concerned with top partner pair production. However, as these bounds become increasingly stringent, the LHC energy will saturate and single top partner production will become more important. We study the LHC sensitivity to single top partner production in a model where the Standard Model (SM) is extended by an SU(2) singlet top partner and a SM gauge singlet scalar, S. In this model, it is possible that the scalar singlet can mediate loop induced gg → T t production, where t is the SM top quark. In fact, we find that the production rate of this channel can be comparable to top partner pair production at top partner masses of MT > 1.5 TeV. In addition, while most current searches focus on the decays T → tZ, T → th, T → Wb decays, in this model the decay pattern of the top partner can be significantly altered with new decay modes T → gt, T → γt, and T → St. We give an overview of the various production and decay channels of the top partner in this model and classify which modes are dominant in which regions of parameter space. We then project the the sensitivity of the high luminosity LHC to gg → T t.

        Speakers: Ian Lewis (The University of Kansas) , K.C. Kong (University of Kansas)
      • 62
        EWBG, alignment and searching for new scalar via triple top signature

        The alignment phenomenon, that the 125 GeV $h^0$ boson so resembles the Standard Model Higgs boson, can be understood in a two Higgs doublet model without discrete symmetry. The Yukawa couplings $\rho_{tt}$ and $\rho_{tc}$ offer new probes for the extra scalar $H^0$ and pseudoscalar $A^0$. We propose to search for $cg \to tH^0$, $tA^0$ followed by $H^0$, $A^0 \to t\bar t$, $t\bar c$, where same-sign dileptons could be the harbinger, with triple-top, in the signature of three leptons plus three $b$-jets, as confirmation. Discovery could touch upon the origin of baryon asymmetry of the Universe.

        Speaker: Dr Tanmoy Modak (National Taiwan University)
      • 63
        Common exotic decays of top partners

        Many Standard Model extensions which address the hierarchy problem contain Dirac-fermion partners of the top quark at the TeV scale. Searches for these vector-like quarks mostly focus on their decay into electroweak gauge bosons and a Standard Model quark.
        In this talk we discuss several classes of composite Higgs models with top partners which have underlying descriptions in terms of a fundamental gauge-fermion dynamics. All of these models contain additional BSM states which are likely to be lighter than the top partners, and which thus provide new decay channels for them. We identify the novel top partner decays which occur most commonly, provide e?ffective Lagrangians and benchmarks, and discuss phenomenological bounds and opportunities for future searches.

        Speakers: Dr Thomas Flacke (IBS CTPU) , Thomas Flacke (Korea University)
    • Dark Matter Detection: Collider 105 (COEX, Seoul)


      COEX, Seoul

      Convener: Chang-Seong Moon (Kyungpook National University (KR))
      • 64
        Searches for dark matter with CMS

        Searches in CMS for dark matter in final states with invisible particles recoiling against visible states are presented. Various topologies and kinematic variables are explored, including jet substructure as a means of tagging heavy bosons. The focus of the talk is the recent results obtained using data collected at Run-II of the LHC.

        Speaker: Andreas Albert (Rheinisch Westfaelische Tech. Hoch. (DE))
      • 65
        New Physics searches at BESIII

        Many models of physics beyond the SM, motivated by the recent astrophysical anomalies, include the possibility of a new types of weak-interacting degrees of freedom. Typical models, such as Next-to-Minimal Supersymmetric SM and Light Hidden Dark-sector model,predict a low-mass Higgs and a Dark Bosons, respectively. The masses and decay modes of these particles are expected to be accessible at the BESIII experiment. BESIII has recently performed searches of light Higgs and Dark Bosons in several decay modes using the data collected at $J/\psi, \psi(2S)$ and $\psi(3770)$ resonances. In the data sample at the $J/\psi$ a search of possible invisible decays of light vector mesons V and pseudo-scalar mesons via $J/\psi \to VP$ decays ($V=\omega, \phi$ and $P=\eta, \eta'$)has also been performed. This talk will summarize BESIII recent results on these searches for new physics.

        Speaker: Shenjian Chen (Nanjing University (CN))
      • 66
        Dark Sector Physics with Belle II

        The Belle II experiment is a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric $e^+ e^-$ collider. The accelerator has already successfully completed the first phase of commissioning in 2016 and first electron positron collisions in Belle II are expected for April 2018. The design luminosity of SuperKEKB 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 the Belle experiment. This data set 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 profit both from the size of the Belle II data, and from specifically designed triggers for the early running of Belle II. This talk will review planned dark sector searches with a focus on the discovery potential of the first data.

        Speakers: Dmitrii Neverov (Nagoya University) , Dmitry Neverov
      • 67
        The investigation on the dark sector at the PADME experiment.

        Among the theoretical models addressing the dark matter problem, the category based on a secluded sector is attracting increasing interest. The PADME experiment, at the Laboratori Nazionali di Frascati (LNF) of INFN, is designed to be sensitive to the production of a low mass gauge boson A’ of a new U(1) symmetry holding for dark particles. This 'dark photon’ is weakly coupled to the photon of the Standard Model, and it provides an experimental signature for one of the simplest implementations of the dark sector paradigm. The DAΦNE Beam-Test Facility of LNF will provide a high intensity, mono-energetic positron beam impacting on a low Z target. The PADME detector will measure with high precision the momentum of a photon, produced along with A’ boson in e+e- annihilation in the target, thus allowing to measure the A’ mass as the missing mass in the final state. This technique, particularly useful in case of invisible decays of the A’ boson, will be exploited for the first time in a fixed target experiment. Simulation studies predict a sensitivity on the interaction strength (ε**2 parameter) down to 10−6, in the mass region 1 MeV<M_A’<22.5 MeV, for one year of data taking with a 550 MeV beam.
        In 2018 the first run will take place, and early data will give the opportunity to compare the detector performance with the design requirements. Intense activity is taking place to deliver and commission the PADME experimental apparatus on site.
        This talk will review the status of the experiment and the prospects.

        Speaker: Paola Gianotti
      • 68
        The Beam Dump eXperiment

        The Beam Dump eXperiment (BDX) is an electron-beam thick-target experiment aimed to investigate the existence of Light Dark Matter (LDM) particles in the MeV-GeV mass range. The experiment has been conditionally approved and is expected to run in a dedicated underground facility located 20 m downstream of the JLab-Hall A beam-dump, receiving up to 10$^{22}$ electrons on target in 1 year time. The detector consists of two main components: a CsI(Tl) electromagnetic calorimeter (Ecal) and a veto system used to suppress the background. The expected signature of the DM interaction in the Ecal is a $\sim$ GeV electromagnetic shower paired with a null activity in the surrounding active veto counters. A complete small-scale prototype of the final detector has been constructed in order to validate the proposed technology and demonstrate the capability to reject the cosmogenic background. Beam-related background was estimated by means of Monte Carlo (MC) simulations. In order to benchmark our simulation tools with on site data, we recently measured, with JLab support, the muon background produced by the 10.6 GeV e$^{-}$-beam on the Hall-A dump at the location of the proposed BDX facility with present shielding configuration. A hodoscope made by a BDX ECal CsI(Tl) crystal sandwiched between a set of segmented plastic scintillators was used to measure the muon rate.
        This talk will present an overview of the BDX experiment with a particular focus on the results of the recent muon-flux measurements and the comparison with the corresponding simulations.

        Speaker: Dr Luca Marsicano (INFN)
      • 69
        Resonance Search for a Heavy Photon with the Heavy Photon Search Experiment

        The Heavy Photon Search (HPS) experiment at Jefferson Lab is searching for a new $U(1)$ vector boson ("heavy photon", "dark photon" or $A'$) in the mass range of 20-500 MeV/c$^2$. An $A'$ in this mass region is natural in hidden sector models of light, thermal dark matter. The $A'$ couples to the ordinary photon through kinetic mixing, which induces its coupling to electric charge. Since heavy photons couple to electrons, they can be produced through a process analogous to bremsstrahlung, subsequently decaying to an $e^{+}e^{-}$, which can be observed as a narrow resonance above the dominant QED trident background. For suitably small couplings, heavy photons travel detectable distances before decaying, providing a second signature. Using the CEBAF electron beam located at the Thomas Jefferson National Accelerator Facility incident on a thin tungsten target, along with a compact, large acceptance forward spectrometer consisting of a silicon vertex tracker and lead tungstate electromagnetic calorimeter, HPS is accessing unexplored regions in the coupling parameter space.

        HPS conducted successful engineering runs in the springs of 2015 using a 1.056 GeV, 50 nA beam and 2016 using a 2.3 GeV, 200 nA beam. This talk will present the results of a resonance search for a heavy photon using the 1165 nb$^{-1}$ (7.29 mC) of data collected during the 2015 engineering run.

        Speaker: Omar Moreno (SLAC National Accelerator Laboratory)
    • Detector: R&D for Present and Future Facilities: 2 103 (COEX, Seoul)


      COEX, Seoul

      Convener: Alexander Oh (University of Manchester (GB))
      • 70
        Expected performance of the upgraded ATLAS experiment for 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 up 3000/fb to 4000/fb of data per experiment. To cope with the expected data-taking conditions ATLAS is planning major upgrades of the detector.

        It is now a critical time for these upgrade projects and during the last year and half ATLAS six Technical Design Reports (TDR) were produced by the ATLAS Collaboration. In these TDRs the physics motivation and benefits of such upgrades are discussed together with details on the upgrade project itself.

        In this contribution we review the expected performance of the upgraded ATLAS detector and the expected reach for physics measurements as well as the discovery potential for new physics that is expected by the end of the HL-LHC data-taking. Performance of object reconstruction under the expected pile-up conditions will be shown, including a fully re-optimized b-tagging algorithm. Important benchmark physics projections including di-Higgs boson production sensitivity will be discussed.

        Speaker: Hector De La Torre Perez (Michigan State University (US))
      • 71
        ATLAS ITk Strip Detector for High-Luminosity LHC

        The ATLAS experiment is currently preparing for an upgrade of the inner tracking for High-Luminosity LHC operation, scheduled to start in 2026. The radiation damage at the maximum integrated luminosity of 4000/fb implies integrated hadron fluencies over 2x10^16 neq/cm2 requiring replacement of the existing Inner Detector. An all-silicon Inner Tracker (ITk) is proposed with a pixel detector surrounded by a strip detector. The current prototyping phase, targeting an ITk Strip Detector consisting of a four-layer central barrel and forward regions composed of six disks at each end, is described in the ATLAS Inner Tracker Strip Detector Technical Design Report (TDR). With the approval of the TDR by the CERN Research Board, the pre-production readiness phase has started at the institutes involved. In this contribution we present the design of the ITk Strip Detector, current status of R&D on various detector components and preparations for production.

        Speaker: Stefania Antonia Stucci (Brookhaven National Laboratory (US))
      • 72
        The upgrade of the CMS ECAL Barrel calorimeter at the HL-LHC for high-precision energy and time measurements

        The electromagnetic calorimeter (ECAL) of the Compact Muon Solenoid Experiment (CMS) has been operating at the Large Hadron Collider (LHC) with proton-proton collisions at 13 TeV center-of-mass energy, with a bunch spacing of 25 ns and instantaneous luminosity exceeding 10^34 cm-2s-1. The CMS ECAL design ensures that its superb performance extends over a very wide range of energies, up to electron and photon energies of ~1 TeV, as required for physics searches beyond the standard model. The Run II running conditions give a first impression of the challenging environment we expect at the high luminosity LHC (HL-LHC). We review the design and R&D studies for the CMS ECAL crystal calorimeter upgrade. Particular challenges at the HL-LHC are the harsh radiation environment, the increasing data rates, and the extreme level of pile-up events, up to 200 simultaneous proton-proton collisions. We present test beam results on hadron irradiated PbWO crystals up to the fluences expected at the HL-LHC and the status of the new readout and trigger electronics R&D. The pile-up mitigation may be substantially improved by means of precision time tagging of calorimeter clusters, by associating them to primary vertices via 4D triangulation. We present test beam results on the precision timing potential of the CMS PbWO crystal calorimeter and discuss how the readout electronics may be adapted to exploit this performance in CMS.

        Speaker: Chiara Ilaria Rovelli (Sapienza Universita e INFN, Roma I (IT))
      • 73
        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 expected increase of the particle flux at the high luminosity phase of the LHC (HL-LHC) with instantaneous luminosities up to L ≃ 7.5 × 10³⁴ cm¯² s¯¹ will have a severe impact on the ATLAS detector performance. The pile-up is expected to increase on average to 200 interactions per bunch crossing. The reconstruction and trigger performance for electrons, photons as well as jets and transverse missing energy will be severely degraded in the end-cap and forward region, where the liquid Argon based electromagnetic calorimeter has coarser granularity and the inner tracker
        has poorer momentum resolution compared to the central region. A High Granularity Timing Detector (HGTD) is proposed in front of the liquid Argon end-cap calorimeters for pile-up mitigation and for bunch per bunch luminosity measurements.

        This device should cover the pseudo-rapidity range of 2.4 to about 4.0. Two Silicon sensors double sided layers are foreseen to provide a precision timing information for minimum ionizing particle with a time resolution better than 50 pico-seconds per hit (i.e 30 pico-seconds per track) in order to assign the particle to the correct vertex. Each readout cell has a transverse size of 1.3 mm × 1.3 mm leading to a highly granular detector with about 3 millions of readout electronics channels. Low Gain Avalanche Detectors (LGAD) technology has been chosen as it provides an internal gain good enough to reach large signal over noise ratio needed for excellent time resolution.

        The requirements and overall specifications of the High Granular Timing Detector at the HL-LHC will be presented as well as the conceptual design. Most recent results on the main R&D will be discussed, with emphasis on the LGAD sensors (sensor optimisation as thickness, dead zone…., and radiation hardness) and ASIC. Beam test results of gain,timing resolution and efficiency will be also shown.

        Speaker: Ariel Gustavo Schwartzman (SLAC National Accelerator Laboratory (US))
      • 74
        The CMS HGCAL detector for HL-LHC upgrade

        The High Luminosity LHC (HL-LHC) will integrate 10 times more luminosity than the LHC, posing significant challenges for radiation tolerance and event pileup on detectors, especially for forward calorimetry, and hallmarks the issue for future colliders. As part of its HL-LHC upgrade program, the CMS collaboration is designing a High Granularity Calorimeter to replace the existing endcap calorimeters. It features unprecedented transverse and longitudinal segmentation for both electromagnetic (ECAL) and hadronic (HCAL) compartments. This will facilitate particle-flow calorimetry, where the fine structure of showers can be measured and used to enhance pileup rejection and particle identification, whilst still achieving good energy resolution. The ECAL and a large fraction of HCAL will be based on hexagonal silicon sensors of 0.5 - 1 cm^2 cell size, with the remainder of the HCAL based on highly-segmented scintillators with SiPM readout. The intrinsic high-precision timing capabilities of the silicon sensors will add an extra dimension to event reconstruction, especially in terms of pileup rejection. An overview of the HGCAL project will be presented, covering motivation, engineering design, readout and trigger concepts, and performance (simulated and from beam tests).

        Speaker: Artur Lobanov (LLR – Ecole Polytechnique (FR))
      • 75
        The Micromegas construction project for the ATLAS New Small Wheel

        In order to meet the requirements of the upcoming luminosity upgrade of the LHC, the Micromegas (MM) technology was selected to be adopted for the New Small Wheel (NSW) upgrade, dedicated to precision tracking. A large surface of the forward regions of the Muon Spectrometer will be equipped with 8 layers of MM modules forming a total active area of 1200 m2. The NSW is scheduled to be installed in the forward region of 1.3 < |η| < 2.7 of ATLAS during the second long LHC shutdown. The NSW will have to operate in a high background radiation region, while reconstructing muon tracks as well as furnishing information for the Level-1 trigger. The project requires fully efficient MM chambers with spatial resolution down to 100 μm, a rate capability up to about 15 kHz/cm2 and operation in a moderate (highly inhomogeneous) magnetic field up to B=0.3 T. The required tracking is linked to the intrinsic spatial resolution in combination with the demanding mechanical accuracy.
        An overview of the design, construction and assembly procedures of the Micromegas modules will be reported. Results and characterization with cosmic rays of the first series module will also be presented.

        Speaker: Athina Kourkoumeli-Charalampidi (Universita and INFN (IT))
      • 76
        Performance and Calibration of 2m^2 -sized 4-layered Micromegas Detectors for the ATLAS Upgrade

        The increased luminosity of the HL-LHC requires a new, high rate capable, high resolution detector technology for the inner end cap of the muon spectrometer of the ATLAS experiment. For this purpose the Micromegas technology is chosen as precision tracker. The SM2 modules are 2 m^2 -sized micromegas quadruplets. This large size requires a sophisticated construction to provide a spatial resolution better than 100 µm. The first series SM2 modules were investigated using 120 GeV pions and muons at SPS/CERN as well as with cosmic muons in a precision facility.

        During the testbeam in August 2017 at the H8 beamline of the SPS 4 small size micropattern detectors were used as tracking reference. The spatial resolution of the SM2 detector is analyzed using two different methods. A charge weighted position reconstruction, the so-called centroid method, achieves a spatial resolution of about 80 µm for perpendicular particle incident. A time projection chamber like approach, the so-called µTPC method, yields a similar resolution for tracks inclined to the active area of the module.

        To investigate and calibrate the full active area of SM2 quadruplets a Cosmic Ray Facility (CRF) is used. It uses two ATLAS Monitored Drift Tube chambers (MDT) to provide precise muon track information in the order of 100 µm. A segmented trigger hodoscope provides additional position information in the order of 10 cm along the wires of the MDTs. The angular acceptance of the CRF is between −30 ◦ and +30 ◦ to the zenith angle over an area of about 8 m^2 .

        We present results for the first series SM2 quadruplets with 12288 channels read out fully by 96 APVs connected to six FEC cards. A segmentation of the active area into smaller partitions enables a detailed analysis of local detector properties, for example geometrical quality, homogeneity in efficiency, in pulse height and in spatial resolution.

        Speaker: Maximilian Herrmann (Ludwig Maximilians Universitat (DE))
    • Heavy Ions: 2 205 (COEX, Seoul)


      COEX, Seoul

      Convener: Andrea Rossi (Universita e INFN, Padova (IT))
      • 77
        Production of open charm and beauty states in pPb collisions with LHCb

        A rich set of open heavy flavour states is observed by LHCb in pPb collisions data collected at 5 and 8.16 TeV nucleon-nucleon center-of-mass energy. Results include the new measurements of production of beauty hadrons in pA collisions through cleanly reconstructed exclusive decays. Open charm states include the Lambda_c baryon, that was also observed in pA collisions for the first time by LHCb.

        Speaker: Benjamin Audurier (Universita e INFN, Cagliari (IT))
      • 78
        Bottomonium production in PbPb collisions from CMS

        The relative yields and the nuclear modification factors of the ground and excited Upsilon states were measured via dimuon channels in PbPb collisions at 5.02 TeV. The analysis was performed as functions of collision centrality, rapidity, and transverse momentum. The results in PbPb are compared with the previous ones in pPb collisions. The results are discussed in terms of the sequential melting scenario in dense partonic matter.

        Speaker: Jaebeom Park (Korea University (KR))
      • 79
        Measurements of strange and non strange beauty production in PbPb collisions at 5.02 TeV with the CMS detector

        Beauty quark production in heavy-ion collisions is considered to be one of the key measurements to address the flavour-dependence of in-medium energy loss in heavy-ion collisions. On the other hand, the measurement of the production of strange beauty mesons can provide fundamental insights into the relevance of mechanisms of beauty recombination in the quark-gluon plasma. In this talk, we will present the state of the art of beauty measurements in PbPb collisions in CMS that includes the $R_{AA}$ measurement of fully reconstructed $B^{+}$ mesons and the latest measurements of non-prompt $D^0$ and $J/\psi$ from B decay over a wide transverse momentum range in the same colliding system. The first measurement of the $B_{s}$ $R_{AA}$ in PbPb collisions will also be presented as well as the ratio between the production yield of $B_{s}$ and $B^{+}$.

        Speaker: Hao Qiu (Purdue University (US))
      • 80
        Strangeness and hadronic resonance production in pp, p-Pb and Pb-Pb collisions measured by ALICE at the LHC

        The measurement of strangeness production is one of the powerful tools to study the thermal properties of the QGP and while strangeness enhancement is a well established experimental observation in heavy ion collisions, its interpretation is still debated.

        In particular the study of (multi-)strangeness particle production as a function of the event multiplicity in different collision systems, reported by ALICE, has shown a smooth increase of strange particles relative to the non-strange ones with event multiplicity.

        We here present the latest results on multiplicity-dependent strangeness production in all the available colliding systems at the top LHC energy. Furthermore, recent measurements of mesonic and baryonic resonances will be presented to discuss the system size dependence, to investigate how hadronic scattering processes affect measured resonance yields, as well as the interplay between canonical suppression and strangeness enhancement.
        The experimental results obtained in pp, p-Pb and Pb-Pb collisions will also be compared with the theoretical predictions.

        Speaker: Jihye Song (Pusan National University (KR))
    • Higgs Physics: 2 201 (COEX, Seoul)


      COEX, Seoul

      Conveners: Sarah Heim (Deutsches Elektronen-Synchrotron (DE)) , Jae Sik Lee (Chonnam National University)
      • 81
        Flavor Changing Neutral Higgs Interactions with Top and Tau at Hadron Colliders

        A general two Higgs doublet model (2HDM) is adopted to study the signature of
        flavor changing neutral Higgs (FCNH) decay
        $\phi^0 \to t\bar{c}+\bar{t}c$ and $\phi^0 \to \tau\mu$, where
        $\phi^0$ could be a CP-even scalar ($H^0$) or a CP-odd pseudoscalar ($A^0$)
        as well as $t \to c h^0$.
        Measurement of the light 125 GeV neutral Higgs boson ($h^0$) couplings at the
        Large Hadron Collider (LHC) favor the decoupling limit or the alignment limit
        of a 2HDM, in which gauge boson and diagonal fermion couplings of $h^0$
        approach Standard Model values.
        In such limit, FCNH couplings of $h^0$ are naturally
        suppressed by a small mixing parameter $\cos(\beta-\alpha)$, while the
        off-diagonal couplings of heavier neutral scalars $\phi^0$ are sustained by
        $\sin(\beta-\alpha) \sim 1$.
        We study physics background from dominant processes with realistic acceptance
        cuts and tagging efficiencies. Promising results are found for the LHC running
        at 13 or 14 TeV collision energies as well as future pp colliders
        at 27 TeV, or 100 TeV.

        Speaker: Chung Kao (University of Oklahoma)
      • 82
        Higgs boson production in decays to two tau leptons using the ATLAS detector

        Measurements of Higgs boson production in Higgs boson decays to two tau leptons based on pp collision data collected at 13 TeV are presented.

        Speaker: Zinonas Zinonos (Munich MPI)
      • 83
        The latest results of the measurement of the Higgs boson decaying to tau lepton pairs at CMS

        The latest results of the measurement of the Higgs boson decaying to tau lepton pairs will be presented. The analysis is performed using data collected with the CMS experiment in 2016 and 2017 at the LHC from pp collisions at centre-of-mass energies of 13 TeV.

        Speaker: Abdollah Mohammadi (Kansas State University (US))
      • 84
        Constraints on CP-violating couplings of the Higgs boson using its decay to fermions in the CMS experiment

        A study of anomalous Higgs boson couplings and CP violation is presented using the Higgs boson decay mode with a pair of fermions in the final state. Associated production of the Higgs boson with two jets is used in this analysis, which is driven by the VBF, VH, and gluon fusion production mechanisms. Constraints on the anomalous couplings and CP-violating parameters are obtained by the CMS experiment with the Run-II data.

        Speaker: Senka Duric (Kansas State University (US))
      • 85
        Learning from Higgs Physics at Future Higgs Factories

        Future Higgs factories can reach impressive precision on Higgs property measurements. In this talk, we explore its sensitivity to new physics models at the electron-positron colliders. In particular, we study two categories of new physics models, Standard Model with a real scalar singlet extension, and Two Higgs Double Model as examples of weakly-interacting models, Minimal Composite Higgs Model and three typical patterns of the more general operator counting for strong interacting models as examples of strong dynamics. We perform a global fit to various Higgs search channels to obtain the 95 C.L. constraints on the model parameter space. We also compare the sensitivity of various future Higgs factories, namely Circular Electron Positron Collider, Future Circular Collider-ee and International Linear Collider.

        Speaker: Shufang Su (University of Arizona)
    • Neutrino Physics: Sterile (I) 202 (COEX, Seoul)


      COEX, Seoul

      Convener: Sunny Seo (IBS)
      • 86
        Reactor antineutrino physics with DANSS experiment

        DANSS is a solid state scintillation detector of reactor antineutrino,
        placed just below 3.1 GW industrial light water reactor of Kalininskaya Nuclear
        Power Plant about 350 km NW from Moscow. A cubic meter sensitive volume of
        the detector is formed by 2500 scintillator strips with individual SiPM
        readout. Groups of 50 strips are also readout by conventional PMTs.
        Reactor antineutrinos are detected by inverse beta-decay (IBD).
        The sensitive volume has passive shielding of copper (5 cm), borated
        polyethylene (two layers of 8 cm), lead (5 cm) and active shielding of
        double layer scintillation counters. The position below reactor
        provides overburden about 50 m.w.e. A movable platform of the detector
        allows to change its distance to the reactor from 10.7 to 12.7 m
        (center to center). 5000 IBD events are detected daily in the
        position closest to the reactor.
        Ratio of the antineutrino spectra at different distances measured
        with the DANSS detector is sensitive to neutrino oscillations to sterile
        neutrinos in the most interesting region of the oscillation parameters
        space (delta m squared ~ 1 eV^2), where the effect is suspected
        by Gallium and Reactor antineutrino anomalies. The DANSS collaboration
        presents results of 1.5 year detector running with three positions
        (10,7, 11.7 and 12.7 m) cycled weekly. The talk covers sterile neutrino
        search results as well as analysis details.

        Speaker: Dr Igor Alekseev (Alikhanov Institute for Theoretical and Experimental Physiscs)
      • 87
        Status of NEOS

        The NEOS experiment has successfully measured the reactor antineutrino energy spectrum at 24 m distance from Hanbit reactor unit 5 for 180 days of reactor operation and constrained the active-to-sterile oscillation parameters. An extended measurement for a whole burnup cycle by the NEOS Phase-II will be a unique probe for the dependence of the reactor antineutrino flux and spectrum on the fuel composition. Physics goal and schedule of the NEOS-II will be presented in this talk.

        Speakers: Yoomin Oh (Institute for Basic Science) , Dr Youngju Ko (Institute for Basic Science (IBS))
      • 88
        PROSPECT, A Precision Reactor Oscillation and SPECTrum Short-Baseline Antineutrino Experiment

        PROSPECT (Precision Reactor Oscillation and Spectrum) is a short-baseline reactor antineutrino experiment. PROSPECT consists of a segmented 4-ton $^{6}$Li liquid scintillator antineutrino detector that will precisely measure the $^{235}{U}$ fission antineutrino spectrum from the High-Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). PROSPECT's high statistics and high resolution measurements of the antineutrino energy spectrum and flux from HFIR's $^{235}$U core will be vital to understanding the discrepancies between predicted and measured antineutrino spectra and fluxes observed in previous commercial power reactor neutrino experiments; in addition, PROSPECT will search for the existence of sterile neutrino oscillations at the eV$^2$-scale. PROSPECT's assembly was completed in late 2017 and physics data taking at HFIR began in 2018. This talk will explain PROSPECT's physics objectives, describe its experimental design, and cover its installation and initial data-taking at ORNL.

        Speakers: Xianyi Zhang (Illinois Institute of Technology) , Xianyi Zhang (Illinois Institute of Technology)
      • 89
        STEREO search for a sterile neutrino at the ILL Grenoble reactor

        In the recent period, re-evaluations of the neutrino flux and spectrum emitted by nuclear reactors have led to the so-called Reactor Antineutrino Anomaly (RAA). This anomaly could be caused by the existence of a light sterile neutrino eigenstate participating in the neutrino oscillation phenomenon. This implies the presence of a fourth mass eigenstate, while global fits of reactor experimental data favor oscillation parameters of the order sin^2(2\theta)=0.1 and Delta m^2=1 eV^2.
        The STEREO experiment was built to search for eV sterile neutrinos at a short baseline of 10 meters from the compact core of the research reactor of the Institut Laue-Langevin (ILL) in Grenoble, France. The segmentation of the detector in six target cells allows for independent measurements of the neutrino spectrum at multiple baselines. STEREO takes data since end of 2016 and started to produce constraining results on an active-sterile flavor oscillation. The talk will describe the STEREO experiment principles and will detail the status of its data analysis.

        Speaker: Mrs Laura Bernard (LPSC, UGA)
      • 90
        Search for Oscillations with a Lithium-6 Detector at the SCK•CEN BR2 reactor

        Several anomalies in the neutrino sector are pointing towards the existence of a new (sterile) neutrino state with a mass around 1 eV. The SoLid experiment is located at the SCK•CEN BR2 research reactor in Belgium and will investigate this possibility. Using the large flux of anti-neutrino generated in the reactor, it will collect a high statistics sample of Inverse Beta Decay (IBD) events. These will be used to study the energy and distance dependence of the neutrino flux, which in turn will be used un-ambiguous support or reject the evidence of sterile neutrinos being the cause of these anomalies.

        The measurement is challenging as one has to operate a detector very close to the high radiation environment of a nuclear reactor and on the surface with little overburden to shield against cosmic rays. SoLid is employing a new technology using highly segmented scintillators with excellent particle ID to face these challenges.

        The 1.6-tons detector was installed towards the end of 2017 and is taking data since early 2018. We will describe the detector design, the experimental setup at BR2 and the detection principle. This will be followed by a first look at the data.

        Speaker: Simon Vercaemer (Universiteit Antwerpen and Vrije Universiteit Brussel)
      • 91
        Updated MiniBooNE Neutrino Oscillation Results within the Context of Global Fits to Short-Baseline Neutrino Data

        In its original 2002-2007 run, MiniBooNE observed an anomalous and yet-unexplained excess of electromagnetic events at low energy neutrino energies. This observation is one of several that has pushed the discussion and search for sterile neutrinos. Since 2016, MiniBooNE has been collecting new neutrino-mode data, doubling the statistics from the original 2002-2007 run. We will revisit the originally observed excess, with one analysis treating the new data as stand alone, and another analysis looking at the combined data. We will then discuss the global fits to the world’s short-baseline neutrino data, focusing on models with sterile neutrinos and including the updated MiniBooNE results.

        Speaker: Alejandro Diaz (Massachusetts Institute of Technology)
    • Quark and Lepton Flavor Physics: 2 102 (COEX, Seoul)


      COEX, Seoul

      Convener: Phillip Urquijo (University of Melbourne (AU))
      • 92
        ATLAS measurements of CP Violation and Rare decays in Beauty mesons

        The ATLAS experiment has performed accurate measurements of mixing and CP violation in the neutral B mesons, and also of rare processes happening in electroweak FCNC-suppressed neutral B-mesons decays. This talk will focus on the latest results from ATLAS, such as rare processes: B^0_s → mu mu and B^0 → mu mu; and CPV in Bs to Jpsi Phi

        Speaker: Iskander Ibragimov (Universitaet Siegen (DE))
      • 93
        Electroweak Penguin B Decays at Belle

        The electroweak penguin B decay process b → s l+ l- is a sensitive probe to New Physics (NP) Recent measurements of angular variable of B → K l+ l- by LHCb and Belle indicate a deviation from the standard model, and further measurements on these process are of interest in the search of NP. In this presentation, we report on the measurements of lepton flavor non universality tests and search for the lepton flavor violating decays in B→K()l+l- and B→Xsl+l-. The analyses are based on the full data set recorded by the Belle detector at the Υ(4S) resonance containing 772 million BBbar pairs from e+ e- collisions produced by the KEKB collider.

        Speaker: Milind Vasant Purohit (University of South Carolina (US))
      • 94
        Lepton Flavour Universality tests at LHCb

        The coupling of the electroweak gauge bosons of the Standard Model (SM) to leptons is lepton flavour universal. Extensions of the SM do not necessarily have this property. Rare decays of heavy flavour are heavily suppressed in the SM and new particles can give sizeable contributions to these processes, their precise study thus allows for sensitive tests of lepton flavour universality. Of particular interest are rare b->sll decays that are well accessible at the LHCb experiment. Recent results from LHCb on lepton flavour universality in rare b->sll decays are discussed.

        Speaker: Biplab Dey (CCNU)
      • 95
        Searches for Lepton Flavour Violating decays at LHCb

        Recent hints for lepton-universality violation in b->clnu and b->sll transitions could imply the existence of lepton-flavour violating B decays. The LHCb experiment is well suited for the search for these decays due to its large acceptance and trigger efficiency, as well as its excellent invariant mass resolution and particle identification capabilities. Recent results on searches for lepton-flavour violating decays from the LHCb experiment will be presented.

        Speaker: Luca Pescatore (EPFL - Ecole Polytechnique Federale Lausanne (CH))
    • Strong Interactions and Hadron Physics: 2 101 (COEX, Seoul)


      COEX, Seoul

      Convener: In Kwon Yoo (Pusan National University (KR))
      • 96
        QCD analysis of the ATLAS and CMS W and Z cross-section measurements and implications for the strange sea density

        In the present paper, the ATLAS inclusive $W^{\pm}$ and $Z$ boson production data are analysed together with the CMS inclusive $W^{\pm}$ and $Z$ boson production data to investigate any possible tensions between the data sets and to determine the strange sea fraction, within the framework of a parton distribution function fit at next-to next-to leading order in perturbative QCD.

        Speaker: Oleksii Turkot (Deutsches Elektronen-Synchrotron (DE))
      • 97
        Constraints on the Parton Density Functions of the Proton by Measurements with the ATLAS Detector

        Parton distribution functions (PDFs) are crucial ingredients for measurements at hadron colliders, since they describe the initial states and therefore critically impact the precision of cross section predictions for observables. This talk will review recent precision analyses, where the PDFs play an important role and discuss the impact of several new ATLAS cross-section measurements on PDFs of the proton.

        Speaker: Claire Gwenlan (University of Oxford (GB))
      • 98
        Parton Distributions, QCD and small-$x$ physics in energy-frontier DIS with the LHeC and the FCC-eh

        Energy-frontier DIS can be realised at CERN through an energy recovery linac that would produce 60 GeV electrons to collide with the HL-LHC or later HE-LHC (LHeC) or eventually the FCC hadron beams (FCC-eh). It would deliver electron-proton collisions with centre-of-mass energies in the range 0.3-3.5 TeV, and luminosities exceeding $10^{34}$ cm$^{−2}$s$^{−1}$. In this talk we will present new studies on the prospects for the precise and complete determination of parton distributions in the proton, both inclusively and in diffractive deep inelastic scattering. We discuss electroweak physics at high scales in ep. We will then embark on the most promising way for establishing the existence of new QCD physics at small $x$, of BFKL type, through the discovery of a new regime beyond the dilute one described by fixed-order perturbation theory.

        Speaker: Claire Gwenlan (University of Oxford (GB))
      • 99
        Investigation of parton densities at very high x

        The knowledge of the proton parton densities for large x is very important in the search for new physics signals at the LHC. For Bjorken-x larger than 0.6 they are however poorly constrained by the data used in extracting the proton parton density functions (PDFs) and different pdf sets have large uncertainties, and differ considerably, in this regime. We compare the pdf sets most widely used by the LHC community to the ZEUS high-$x$ data. This data has not been previously used in pdf set determinations. Due to the small expected and observed numbers of events in this kinematic regime, Poisson statistics is used in the evaluation of the probabilities assigned to the different pdf sets. A wide variation is found in the ability of the PDF sets to predict the observed results.

        Speaker: Claire Gwenlan (University of Oxford (GB))
      • 100
        Studies of HERA deep inelastic scattering data at low Q^2 and low x_Bj

        A phenomenological study of the final combined HERA data on inclusive deep inelastic scattering (DIS) has been performed. The data are presented and investigated for a kinematic range extending from values of the four-momentum transfer, $Q^2$, above $10^4$ GeV$^2$ down to the lowest values observable at
        HERA of $Q^2 = 0.045$ GeV$^2$ and Bjorken $x$, $x_{\rm Bj} = 6 \times 10^{−7}$. The data are well described by fits based on perturbative quantum chromodynamics (QCD) using collinear factorisation and evolution of the parton densities encompassed in the DGLAP formalism from the highest $Q^2$ down to $Q^2$ of a few GeV$^2$. The standard DGLAP evolution was augmented by including an additional higher-twist term in the description of the longitudinal structure function, $F_L$. This additional term, $F_L A_L^{\rm HT}/Q^2$, improves the description of the reduced cross sections significantly. The resulting predictions for F_L suggest that further corrections are required for $Q^2$ less than about 2 GeV$^2$. The Regge formalism can describe the data up to $Q^2 \sim 0.65$ GeV$^2$. The complete data set can be described by a new fit using the ALLM parameterisation. The region between the Regge and the perturbative QCD regimes is of particular interest.

        Speaker: Dr Volodymyr Myronenko (Deutsches Elektronen-Synchrotron)
      • 101
        Probing the strange content of the proton via charm production in charged-current deep inelastic scattering at HERA

        The production of charm quarks in charged current interactions at HERA is investigated using the ZEUS detector. The present analysis considers measurements taken in HERA II period (2003 - 2007) where major detector upgrades were implemented at ZEUS. With an integrated luminosity of about 350 pb$^{-1}$), the HERA II data has enough statistics to probe the strangeness in the proton via charm production at high $Q^2$ in charged current deep inelastic scattering (CC DIS). The life-time tagging method was used to select charm events, suppressing the light-flavour contribution in the CC cross section. The charm cross section measurement in CC DIS at HERA as well as estimation of major systematics is presented and compared with theoretical expectations.

        Speaker: Jae Nam (Temple University)
    • Top Quark and Electroweak Physics: 2 209 (COEX, Seoul)


      COEX, Seoul

      Convener: Freya Blekman (IIHE, Vrije Universiteit Brussel (BE))
      • 102
        Forward-backward asymmetry in $p\bar p \to t\bar t$ events at the Tevatron

        We discuss the asymmetry between yields of forward- and backward-produced top and antitop quarks in $p\bar p \to t\bar t$ events at the Tevatron collider. These measurements use the full Run II data set in lepton plus jets and dilepton channels, recorded in the D0 and CDF detectors, corresponding to an integrated luminosity of $\approx 2\times10\ $fb$^{-1}$ . The combinations of inclusive and differential asymmetries are presented and compared with recent standard model predictions.

        Speaker: Bob Hirosky (University of Virginia (US))
      • 103
        Measurements of ttbar+X using the ATLAS detector

        The large centre-of-mass energy available at the proton-proton collider LHC allows for the copious production of top quark pairs in association with other final state particles at high transverse momenta. The ATLAS experiment has measured several final state observables that are sensitive to additional radiation in top anti-top quark final states. Results on the top production in association with W and Z bosons are presented as well as top pair production with a photon or with b quarks. These measurements are compared to modern Monte Carlo generators based on NLO QCD matrix elements.

        Speaker: Marisa Sandhoff (Bergische Universitaet Wuppertal (DE))
      • 104
        Rare top quark production in CMS: ttW, ttZ, ttgamma, tZ, tgamma, and tttt production

        A comprehensive set of measurements of top quark pair and single top quark production in association with EWK bosons (W, Z or ɣ) is presented. The results are compared to theory predictions and re-interpreted as searches for new physics inducing deviations from the standard model predictions using an effective field theory approach. The status of the search for four top quark production, to which the LHC experiments are starting to be sensitive, and that has important BSM re-interpretations, is also reported.

        Speaker: Nicolas Pierre Chanon (Centre National de la Recherche Scientifique (FR))
      • 105
        Anomalous top quark couplings, FCNC, and EFT interpretations in CMS

        Top quark production can probe physics beyond the SM in different ways. Some processes, and especially certain angular correlations, are sensitive to the existence of anomalous top quark couplings. In the SM, flavour-changing neutral currents (FCNC) are forbidden at tree level and are strongly suppressed in loop corrections. Several extensions of the SM incorporate significantly enhanced FCNC behaviour that can be directly probed in top quark processes. Current approaches adopting an EFT framework allow describing effects of new physics in a model independent way. This talks reviews the current limits on possible anomalous couplings of the top quark, FCNC searches in the top sector, and EFT interpretations.

        Speaker: Alexander Josef Grohsjean (Deutsches Elektronen-Synchrotron (DE))
      • 106
        Searches for rare top quark couplings with the ATLAS detector

        The top quark is the heaviest known fundamental particle and probing its couplings with the other fundamental particle may open a window to physics beyond the Standard Model. Searches for flavour-changing neutral current top-quark interactions are discussed based on the 13 TeV ATLAS dataset. Searches for rare top quark decays to Higgs and Z bosons are presented in top quark pair production, and searches for rare top quark interactions with gluons and Z bosons are presented in single top quark production.

        Speaker: Dr Ligang Xia (University of Warwick (GB))
    • 12:30 PM
    • Accelerators: Physics, Performance, and R&D for Future Facilities: Accelerator Physics/Technology 205 (COEX, Seoul)


      COEX, Seoul

      Convener: Manqi Ruan (Chinese Academy of Sciences (CN))
      • 107
        First Ever Ionization Cooling Demonstration in MICE

        The Muon Ionization Cooling Experiment (MICE) at RAL has studied the ionization cooling of muons. Several million individual particle tracks have been recorded passing through a series of focusing magnets in a number of different configurations and a liquid hydrogen or lithium hydride absorber.
        Measurement of the tracks upstream and downstream of the absorber has shown the expected effects of the 4D emittance reduction. This invited talk presents and discusses these results, and projects the
        future of ionization cooling.

        Speaker: Chris Rogers (STFC)
      • 108
        Recent results from MICE on multiple Coulomb scattering and energy loss

        Multiple Coulomb scattering and energy loss are well known phenomena experienced by charged particles as they traverse a material. However, from recent measurements by the MuScat collaboration, it is known that the available simulation codes (GEANT4, for example) overestimate the scattering of muons in low Z materials. This is of particular interest to the Muon Ionization Cooling Experiment (MICE) collaboration which has the goal of measuring the reduction of the emittance of a muon beam induced by energy loss in low Z absorbers. MICE took data without magnetic field suitable for multiple scattering measurements in
        the fall of 2015 with the absorber vessel filled with xenon and in the spring of 2016 using a lithium hydride absorber. In the fall of 2016 MICE took data with magnetic fields on and measured the energy loss of muons in a lithium hydride absorber. These data are all compared with the Bethe-Bloch formula and with the predictions of various models, including the default GEANT4 model.

        Speaker: Scott Wilbur (University of Sheffield)
      • 109
        Progress on the 650MHz/800kW CW klystron development at IHEP

        The configurations of the CEPC and the SPPC were proposed in September, 2012. To reduce the costs of the construction and the operation, high efficiency klystrons is preferred for the Collider ring. In this scenario, the plan to develop the high efficiency 650MHz/800kW CW klystron with an ultimate goal of 80% is initialized. Since there are no any experiences and infrastructures such as the large baking furnace and the high power testing stand to develop these kind of high power CW klystrons in China, the 1st klystron prototype is based on the conventional 2nd harmonic bunching technology, then more klystron prototypes will be made with steady improvement of the efficiency. In this paper, the progress on the 1st 650MHz/800kW CW klystron prototype development at IHEP is presented. Till now, the mechanical design of the 1st klystron prototype has been finished; the fabrication will be started soon. In addition, the design of the 2nd klystron prototype and the strategic plan to progressively increase the klystron efficiency will also be shown.

        Speaker: Shengchang Wang (IHEP)
      • 110
        Progress on stabilising relativistic lepton beams for future colliders

        We report progress on stabilising relativistic electron beams, in terms of their position and arrival time, for achieving high luminosity at future lepton colliders such as the International Linear Collider (ILC) and the Compact Linear Collider (CLIC). Hardware has been developed and deployed at the Accelerator Test Facility (ATF) at KEK for measuring and stabilising the beam position at the final focus to the nanometre level. We report latest closed-loop feedback tests in which the beam position was stabilised to c. 40 nm. In addition, a beam phase feed-forward system was deployed at the CLIC Test Facility (CTF3) at CERN. We report the results of recent beam tests in which the beam arrival time was stabilised to c. 50 femtoseconds, which meets the requirement for efficient power transfer between the CLIC drive and main beams in the two-beam accelerator complex.

        Speaker: Philip Nicholas Burrows (University of Oxford (GB))
    • Astro-particle Physics and Cosmology: 3 104 (COEX, Seoul)


      COEX, Seoul

      Convener: Prof. Seong Chan Park (Yonsei University)
      • 111
        Leptogenesis in Cosmological Relaxation with Particle Production

        Among cosmological relaxation solutions to the weak-scale hierarchy problem, gauge boson production is a particularly efficient backreaction mechanism for trapping the relaxion. In these models, scanning can even happen after inflation and the relaxion field range can be sub-Planckian, with no extremely small parameters or large e-foldings involved. We consider a model where particle production by the relaxion also reheats the universe and generates the baryonic matter-antimatter asymmetry. Out-of-equilibrium leptons scatter with the thermal bath through interactions that violate CP and lepton number via higher-dimensional operators. Such an effective field theory setup, with no new physics below the cut-off, is sufficient to achieve successful leptogenesis. The baryon asymmetry is thus intrinsically tied to a weak-scale hierarchy.

        Speakers: Dr Fang Ye (KAIST) , Dr Fang Ye (KAIST)
      • 112
        Dark matter assisted Dirac leptogenesis and neutrino mass

        We propose a minimal extension of the standard model with U(1)_B−L × Z_2 symmetry. In this model by assuming that the neutrinos are Dirac (i.e. B − L is an exact symmetry), we found a simultaneous solution for non zero neutrino masses and dark matter content of the universe. The observed baryon asymmetry of the universe is also explained using Dirac Leptogenesis, which is assisted by a dark sector, gauged under a U(1)_D symmetry. The latter symmetry of the dark sector is broken at a TeV scale and thereby giving mass to a neutral gauge boson Z_D . The standard model Z-boson mixes with the gauge boson Z_D at one loop level and thus paves a way to detect the dark matter through spin independent elastic scattering at terrestrial laboratories.

        Speaker: Mr Narendra Nimmala (Indian Institute of Technology, Hyderabad)
      • 113
        Cosmological Helical Hypermagnetic Fields and Baryogenesis

        I will show that the baryon asymmetry of the Universe (BAU) is generated from the hypermagnetic helicity decay without being washed out by the sphalerons. Moreover such hypermangetic fields still remain until today as the intergalactic magnetic fields, which will be the smoking gun of the scenario. I will also discuss a possible mechanism to generate such hypermagnetic fields. That is, the chiral instability induced by a large chiral asymmetry in the early Universe thermal plasma, which can be generated by the SU(5) GUT baryogenesis. Although the SU(5) GUT baryogenesis has been thought not to be a viable model for the BAU since the asymmetry is washed out by the sphalerons, it can be indirectly responsible for the BAU through the maximally helical hypermagnetic field generation.

        Speakers: Kohei Kamada (Institute for Basic Science) , Kohei Kamada (Institute for Basic Science)
      • 114
        Non-thermal WIMP baryogenesis

        We propose a WIMP baryogensis achieved by the annihilation of non-thermally produced WIMPs from decay of heavy particles, which can result in low reheating temerature. Dark matter (DM) can be produced non-thermally during a reheating period created by the decay of long-lived heavy particle, and subsequently re-annihilate to lighter particles even after the thermal freeze-out. The re-annihilation of DM provides the observed baryon asymmetry as well as the correct relic density of DM. We investigate how wahout effects can affect the generation of the baryon asymmetry and study a model suppressing them. In this scenario, we find that DM can be heavy enough and its annihilation cross section also can be larger than that adopted in the usual thermal WIMP baryogenesis.

        Speaker: Mr Jongkuk Kim (Sungkyunkwan University)
      • 115
        Kaluza-Klein Towers in the Early Universe: Phase Transitions, Relic Abundances, and Applications to Axion Cosmology

        We discuss the early-universe cosmology of a Kaluza-Klein (KK) tower of scalar fields in the presence of a mass-generating phase transition, focusing on the time-development of the total tower energy density as well as its distribution across the different KK modes. We find that both of these features are extremely sensitive to the details of the phase transition and can behave in a variety of ways significant for late-time cosmology. In particular, the interplay between the temporal properties of the phase transition and the mixing it generates are responsible for both enhancements and suppressions in the late-time abundances, sometimes by orders of magnitude. We map out the complete model parameter space and determine where traditional analytical approximations are valid and where they fail. Finally, we apply this machinery to the example of an axion-like field in the bulk, mapping these phenomena over an enlarged axion parameter space that extends beyond those accessible to standard treatments.

        Speaker: Dr Jeff Kost (Institute of Basic Science)
      • 116
        The spectrum of the axion dark sector, cosmological observable and black hole superradiance constraints.

        Axions or axion-like particles are ubiquitous in many theoretical extensions of the Standard Model of particle physics, in particular the ''string axiverse'' scenario [1-3]. If the phenomenologically defining parameters, the axion mass, $m_a$, and (effective) decay constant, $f_a$, fall in specific ranges, then axions contribute to the cosmological dark matter and dark energy densities of the universe [4]. In the framework of string/M theory a systematic construction of the axion decay constant and mass spectrum in explicit realisations of the string axiverse is a daunting task to undertake, often requiring the extensive details of instanton corrections to the superpotential and a detailed knowledge of the full scalar potential for the supersymmetric theory when considering realistic axion/moduli population numbers.

        We present the background cosmological (quasi-)observables for a series of random matrix (RMT) models inspired by several axion field alignment mechanisms [5,6], with the associated parameter spectra for a large number of axion fields, $n_{\rm ax}\sim \mathcal{O}(10-100)$, where the masses and decay constants are drawn from statistical distributions [7]. Using the RMT formalism we also consider the spectra of more physically motivated models, specifically a class of $G_2$ compactified M-theory models [3,8,9] where all the moduli are stabilised in a non-supersymmetric minima. This process effectively reduces the number of parameters from $2n_{\rm ax}$ to a limited number of ''hyperparameters'' allowing us to use Bayesian methods to constrain the hyperparameters of the distributions in the context of the cosmological (quasi)-observables.

        These methods are also used to constrain the axion parameter space via the black hole superradiance process [10,11]. The presence of multiple fields can enhance the exclusion bounds on both solar and supermassive black holes in the so called Regge spin plane as apposed to considering just a single field. We present an analysis of the statistical likelihoods for each of these models with recorded black hole data in order to provide a picture of the significance of the axion parameter space its phenomenology in effective theories.

        Speaker: Mr Matthew Stott (King's College London)
      • 117
        The generation of B-mode and circular polarization of cosmic photons due to NonCommutative space-Time background

        In standard model of cosmology, B-mode polarization of the CMB can be generated due to the tensor perturbation of metric which is related to gravitational effects in the inflation epoch and scalar perturbation can not explain B-mode polarization. We consider Compton scattering in non-commutative framework and show that Compton scattering in presence of non-commutative background and scalar mode of perturbation, beside generating a circularly polarized microwave, can leads to a B-mode polarization of the Cosmic Microwave Background.

        Speaker: Dr Seddigheh Tizchang (Institute for Research in Fundamental Sciences (IPM))
    • Beyond the Standard Model: 3 203 (COEX, Seoul)


      COEX, Seoul

      Convener: Paul Douglas Jackson (University of Adelaide)
      • 118
        Searches for SUSY with boosted objects at CMS

        Searches for supersymmetry at the LHC have pushed the mass limits for strongly-produced sparticles to the TeV level and make the reconstruction and identification of boosted objects to an essential tool for current and future searches for supersymmetry. These objects can originate from the final stage of a short decay chain, or arise heavy gauge or Higgs bosons produced in a decay chain. The talk summaries the use of large-radius jets and substructure techniques in searches such as the ones for the pair production of gluinos or third generation squarks in proton-proton collisions at 13 TeV.

        Speaker: Rishi Gautam Patel (University of Colorado Boulder (US))
      • 119
        Searches for strongly-produced SUSY at CMS

        Searches for the pair-production of colored supersymmetric particles are presented. The results cover different scenarios of gluino and squark production, including models of split supersymmetry that predict long-lived gluinos. The results are based on proton-proton collisions recorded at sqrt(s) = 13 TeV with the CMS detector.

        Speaker: Ana Ovcharova (Univ. of California Santa Barbara (US))
      • 120
        Searches for squarks and gluinos in final states involving dark matter candidates with ATLAS

        Despite the absence of experimental evidence, weak-scale supersymmetry remains one of the best motivated and studied Standard Model extensions. This talk summarises recent ATLAS results on inclusive searches for supersymmetric squarks of the first two generations, and gluinos in R-parity conserving models that predict dark matter candidates. The searches target final states including jets, leptons, photons, and missing transverse momentum.

        Speaker: Dr Hernan Wahlberg (La Plata)
      • 121
        Searches for direct pair production of stops and sbottoms with the ATLAS detector

        Naturalness arguments for weak-scale supersymmetry favour supersymmetric partners of the third generation quarks with masses not too far from those of their Standard Model counterparts. The phenomenology ranges from final states of top or bottom quark pairs and two dark matter candidates, to more complex scenarios involving non-prompt sparticle decays or R-parity violating signatures. This talk presents recent ATLAS results from searches for direct sbottom and stop pair production focusing on the less conventional scenarios.

        Speaker: Dr Giacomo Polesello (Pavia)
      • 122
        Searches for long-lived particles and other non-conventional signatures at CMS

        Many extensions of the standard model including SUSY predict new particles with long lifetimes, such that the position of their decay is measurably displaced from their production vertex, and particles giving rise to other non-conventional signatures. We present recent results of searches for long-lived particles and other non-conventional signatures obtained using data recorded by the CMS experiment at Run-II of the LHC.

        Speaker: Alberto Escalante Del Valle (Austrian Academy of Sciences (AT))
      • 123
        Reconstruction techniques in supersymmetry searches in the ATLAS experiment

        Many supersymmetric scenarios feature final states with non-standard final state objects. The production of massive sparticles can lead to the production of boosted top quarks or vector bosons, high-pt b-jets. At the same time, transitions between nearly mass-degenerate sparticles can challenge the standard reconstruction because of the presence of very soft leptons or jets. The talk will review the application of innovative reconstruction techniques to supersymmetry searches in ATLAS.

        Speaker: Dr Mark Hodgkinson (Sheffield)
      • 124
        Test of Beyond-Standard-Model Scenarios with sub-keV Germanium Detectors

        The existence of physics beyond the standard model (BSM) is established with the observation of neutrino flavor oscillations. Germanium detectors with their excellent energy response and sub-keV sensitivities [1] provide a unique tool to probe a class of BSM scenarios. The TEXONO Collaboration [2] has been pursuing these studies experimentally, complemented by adaptation of advanced atomic physics theory techniques to derive neutrino interaction cross-sections at atomic-scale energy. We will present highlights of the studies on neutrino electromagnetic interactions [3] as well as constraints on sterile neutrinos, axions and dark photons [4]. Additional subjects along these lines will also be discussed.
        1. A.K. Soma et al., Nucl. Instrum. Meth. A 836, 67 (2016).
        2. H.T. Wong, The Universe 3 22, 2015.
        3. J.-W. Chen et al., Phys. Rev. D 90, 011301(R) (2014); J.-W. Chen et al., Phys.Rev. D 91,013005 (2015).
        4. J.-W. Chen et al., Phys. Rev. D93, 093012 (2016); S.K. Liu et al., Phys. Rev. D 95, 052006 (2017); S. Bilmus et al, Phys. Rev. D 92, 033009 (2015).

        Speaker: Dr Lakhwinder Singh . (Institute of Physics, Academia Sinica, Taipei 11529, Taiwan)
    • Computing and Data Handling: Machine Learning 1 201 (COEX, Seoul)


      COEX, Seoul

      Convener: Sang Un Ahn (Korea Institute of Science & Technology Information (KR))
      • 125
        Machine learning at CERN: ALICE, CMS, and other developments

        Machine learning is of increasing importance to high energy physics as dataset sizes and data rates grow, while sensitivity to standard model and new physics signals are continually pushed to new extremes. Machine learning has proven to be advantageous in many contexts, and applications now span areas as diverse as triggering, monitoring, reconstruction, simulation, and data analysis. This talk will discuss a subset of the applications of machine learning in the ALICE and CMS experiments, as well as other areas of more general use in high energy physics at CERN.

        Speaker: Markus Stoye (Imperial College (GB))
      • 126
        Machine learning at CERN: ATLAS, LHCb, and other developments

        Machine learning is of increasing importance to high energy physics as dataset sizes and data rates grow, while sensitivity to standard model and new physics signals are continually pushed to new extremes. Machine learning has proven to be advantageous in many contexts, and applications now span areas as diverse as triggering, monitoring, reconstruction, simulation, and data analysis. This talk will discuss a subset of the applications of machine learning in the ATLAS and LHCb experiments, as well as other areas of more general use in high energy physics at CERN.

        Speaker: Steven Schramm (Universite de Geneve (CH))
      • 127
        TrackML : a tracking Machine Learning challenge

        To attain its ultimate discovery goals, the luminosity of the Large Hadron Collider at CERN will increase so the amount of additional collisions will reach a level of 200 interaction per bunch crossing, a factor 7 w.r.t the current (2017) luminosity. This will be a challenge for the ATLAS and CMS experiments, in particular for track reconstruction algorithms. In terms of software, the increased combinatorial complexity will have to harnessed without any increase in budget.
        To engage the Computer Science community to contribute new ideas, we organized a Tracking Machine Learning challenge (TrackML) running on the Kaggle platform from March to June 2018, building on the experience of the successful Higgs Machine Learning challenge in 2014.
        The data were generated using [ACTS] (http://acts.web.cern.ch/ACTS/latest/doc/index.html), an open source accurate tracking simulator, featuring a typical all silicon LHC tracking detector, with 10 layers of cylinders and disks. Simulated physics events (Pythia ttbar) overlaid with 200 additional collisions yield typically 10’000 tracks (100’000 hits) per event.

        The task to be performed by participants in the challenge is the “pattern recognition”: associate the hits to tracks corresponding to the original charged particles. The participants are given 100’000 events (including truth information) to train their algorithm, while the evaluation by Kaggle is run on 100 other events. The score used to rank the candidates is the fraction of hits correctly assigned, with a weighting mechanism to favor higher momentum tracks and hits in the innermost and outermost detector layers. In this challenge, there is no CPU constraint, however a second phase of the challenge to be run during the summer will have strong computational constraints.
        The emphasis of the challenge is to explore innovative Machine Learning approaches, rather than hyper-optimising known combinatorial approaches. In preliminary discussions with the ML community, Convolutional Neural Network, LSTM, Deep Neural Nets, Monte Carlo Tree Search, geometric Deep Learning have been mentioned. A very simplified 2D version of the challenge (see reference) was successfully run as a two day hackathon in March 2017.

        In this talk, the first lessons from the challenge (which will just have been completed) will be discussed. What algorithms have emerged and are the most promising ? How robust is the score, compared to deeper performance evaluations ?

        Speaker: Tobias Golling (Universite de Geneve (CH))
      • 128
        Application of machine learning techniques at BESIII experiment

        The BESIII detector is a general purpose spectrometer located at BEPCII. BEPCII is a double ring e+e− collider running at center of mass energies between 2.0 and 4.6 GeV and has reached a peak luminosity of $1\times 10^{33} $cm$^{−2}$s$^{−1}$ at $\sqrt(s) = 3770$ MeV. As an experiment in the high precision frontier of hadron physics, since 2009, BESIII has collected the world's largest data samples of $J/\psi$ , $\psi(3686)$, $\psi(3770)$, $\psi(4040)$ and $\psi(4260)$ decays. These data are being used to make a variety of interesting and unique studies of light hadron spectroscopy, charmonium spectroscopy and high-precision measurements of charmed hadron decays.
        Machine learning techniques have been employed to improve the performance of BESIII software. Novel approaches for “particle identification of lepton” and “track segment building for the CGEM (Cylindrical Gas Electron Multiplier Inner Tracker)” will be discussed. The comparison of performances with traditional approaches will be given.

        Speaker: Beijiang Liu
      • 129
        Particle identification at LHCb: new calibration techniques and machine learning classification algorithms

        Particle identification (PID) plays a crucial role in LHCb analyses. Combining information from LHCb subdetectors allows one to distinguish between various species of long-lived charged and neutral particles. PID performance directly affects the sensitivity of most LHCb measurements. Advanced multivariate approaches are used at LHCb to obtain the best PID performance and control systematic uncertainties. This talk highlights recent developments in PID that use innovative machine learning techniques, as well as novel data-driven approaches which ensure that PID performance is well reproduced in simulation.

        Speaker: Anton Poluektov (University of Warwick (GB))
      • 130
        Fast calorimeter simulation in LHCb

        In HEP experiments CPU resources required by MC simulations are constantly growing and become a very large fraction of the total computing power (greater than 75%). At the same time the pace of performance improvements from technology is slowing down, so the only solution is a more efficient use of resources. Efforts are ongoing in the LHC experiments to provide multiple options for simulating events in a faster way when higher statistics is needed. A key of the success for this strategy is the possibility of enabling fast simulation options in a common framework with minimal action by the final user. In this talk we will describe the solution adopted in Gauss, the LHCb simulation software framework, to selectively exclude particles from being simulated by the Geant4 toolkit and to insert the corresponding hits generated in a faster way. The approach, integrated within the Geant4 toolkit, has been applied to the LHCb calorimeter but it could also be used for other subdetectors. The hits generation can be carried out by any external tool, e.g. by a static library of showers or more complex machine-learning techniques. In LHCb generative models, which are nowadays widely used for computer vision and image processing are being investigated in order to accelerate the generation of showers in the calorimeter. These models are based on maximizing the likelihood between reference samples and those produced by a generator. The two main approaches are Generative Adversarial Networks (GAN), that takes into account an explicit description of the reference, and Variational Autoencoders (VAE), that uses latent variables to describe them. We will present how both approaches can be applied to the LHCb calorimeter simulation, their advantages as well as their drawbacks.

        Speaker: Fedor Ratnikov (Yandex School of Data Analysis (RU))
      • 131
        New approaches using machine learning for fast shower simulation in ATLAS

        Modeling the detector response to collisions is one of the most CPU expensive and time-consuming aspects in the LHC. The current ATLAS baseline, GEANT4, is highly CPU intensive. With the large collision dataset expected in the future, CPU usage becomes critical. During the LHC Run-1, a fast calorimeter simulation (FastCaloSim) was successfully used by ATLAS. FastCaloSim parametrizes the energy response of particles in the calorimeter cells, accounting for the lateral shower profile and the correlation of the energy deposition among various calorimeter layers. It significantly speeds up the calorimeter simulation. An improved version of FastCaloSim is currently under development to reduce CPU and memory requirements and to improve the physics description. The new FastCaloSim implements machine learning techniques, such as principal component analysis and neural networks. Other new ideas being investigated include using deep generative models such as Variational Auto-Encoders (VAEs) and Generative Adversarial Networks (GANs). These models take into account the complex geometry of the ATLAS calorimeter and reproduce the shower characteristics. They are enhanced to handle different particle types and energy level variations simultaneously. This talk will describe these fast simulation methods, quantify the performance and discuss physics applications.

        Speaker: Hasib Ahmed (The University of Edinburgh (GB))
    • Detector: R&D for Present and Future Facilities: 3 202 (COEX, Seoul)


      COEX, Seoul

      Convener: Alexander Oh (University of Manchester (GB))
      • 132
        The design and layout of the Phase-II upgrade of the Inner tracker of the ATLAS experiment

        In the high luminosity era of the Large Hadron Collider (HL-LHC), the instantaneous luminosity is expected to reach unprecedented values, resulting in about 200 proton-proton interactions in a typical bunch crossing. To cope with the resultant increase in occupancy, bandwidth and radiation damage, the ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk), aiming to provide tracking coverage up to |η|<4. The ITk consists of an inner pixel and an outer strip detector designed to provide a tracking performance at least as good as the current detector, but in the HL-LHC environment. In this talk, the updated layout of the detector for the pixel technical design report is presented, and the expected detector and tracking performance is discussed.

        Speaker: Francesco Costanza (Centre National de la Recherche Scientifique (FR))
      • 133
        The CMS Tracker Upgrade for the High Luminosity LHC

        The LHC machine is planning an upgrade program which will smoothly bring the luminosity at about 5*10^34cm-2s-1 in 2028, to possibly reach an integrated luminosity of 3000fb-1 by the end of 2037. This High Luminosity LHC scenario, HL-LHC, will require a preparation program of the LHC detectors known as Phase-2 upgrade. The current CMS Outer Tracker, already running beyond design specifications, and CMS Phase1 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 high-demanding operating conditions and the delivered luminosity. The new Outer Tracker should have also trigger capabilities. To achieve such goals, R&D activities are ongoing to explore options either for the Outer Tracker, either for the pixel Inner Tracker. Solutions are being developed that would allow including tracking information at Level-1. The design choices for the Tracker upgrades are discussed along with some highlights of the R&D activities.

        Speaker: Martin Delcourt (Universite Catholique de Louvain (UCL) (BE))
      • 134
        Upgrades of the CMS muon system in preparation of HL-LHC

        The present CMS muon system operates three different detector types: in the barrel drift tubes (DT) and resistive plate chambers (RPC), cathode strip chambers (CSC) and RPCs in the forward regions. In order to cope with the challenging conditions of increasing luminosity, several upgrades are planned to the trigger and muon systems. For the existing DT and CSC detectors, the electronics will be upgraded to handle higher rates. Accelerated ageing tests are being performed to study the behaviour of these detectors under conditions which are one order of magitude beyond the design values. New micro-pattern gas detectors will be added to improve the performance in the critical forward region. Those detectors - large-area triple-foil gas electron multiplier (GEM) detectors - will already be installed in upcoming long shutdown in the pseudo-rapidity region 1.6 < eta < 2.4. Only with those additional high resolution detectors, the rate of background triggers can be controlled while maintaining high trigger efficiency for low transverse momentum muons. For the HL-LHC operation the muon forward region should be enhanced with another large area GEM based station, called GE2/1, and with two new generation RPC stations, called RE3/1 and RE4/1, having low resistivity electrodes. These detectors will combine tracking and triggering capabilities and can stand particle rates up to few kHz/cm2. In addition to take advantage of the pixel tracking coverage extension a new detector, ME0 station, behind the new forward calorimeter, covering up to |η| = 3.

        Speaker: Anna Colaleo (Universita e INFN, Bari (IT))
      • 135
        The upgrade of the ATLAS Muon System for High-Luminosity LHC

        The muon spectrometer of the ATLAS detector will undergo a major upgrade during the Long Shutdown 3, in order to cope with the operational conditions at the high-luminosity LHC. The trigger and readout system will be completely redesigned, to support Level-0 trigger rates of 1--4 MHz and a latency of 10 us.
        To do so, the readout electronics of all the trigger and precision chambers will be replaced and the  precision chambers, that at the moment are not included in the hardware trigger, will be integrated into the Level-0 trigger in order to sharpen the momentum threshold and increase the system redundancy. New-generation RPC chambers will be installed in the inner barrel layer to increase the acceptance and robustness of the trigger. Some of the MDT chambers in the inner barrel layer will be replaced with new small-diameter MDTs. New TGC triplet chambers in the barrel-endcap transition region will replace the current TGC doublets to suppress the high trigger rate from random coincidences in this region. A major upgrade of the power system is also planned. The Phase-II upgrade concludes the process of adapting the muon spectrometer to the ever increasing performance of the LHC, which started with the Phase-I upgrade New Small Wheel (NSW) project that will replace the innermost endcap wheels.

        Speaker: Yasuyuki Horii (Nagoya University (JP))
      • 136
        Small-Strip Thin Gap Chambers for the Muon Spectrometer Upgrade of the ATLAS Experiment

        The instantaneous luminosity of the Large Hadron Collider at CERN will be increased up to a factor of five with respect to the design value by undergoing an extensive upgrade program over the coming decade. Such increase will allow for precise measurements of Higgs boson properties and extend the search for new physics phenomena beyond the Standard Model. The largest phase-1 upgrade project for the ATLAS Muon System is the replacement of the present first station in the forward regions with the so-called New Small Wheels (NSWs) during the long-LHC shutdown in 2019/20. Along with Micromegas, the NSWs will be equipped with eight layers of small-strip thin gap chambers (sTGC) arranged in multilayers of two quadruplets, for a total active surface of more than 2500 m$^2$. All quadruplets have trapezoidal shapes with surface areas up to 2 m$^2$. To retain the good precision tracking and trigger capabilities in the high background environment of the high luminosity LHC, each sTGC plane must achieve a spatial resolution better than 100 μm to allow the Level-1 trigger track segments to be reconstructed with an angular resolution of approximately 1mrad. The basic sTGC structure consists of a grid of gold-plated tungsten wires sandwiched between two resistive cathode planes at a small distance from the wire plane. The precision cathode plane has strips with a 3.2mm pitch for precision readout and the cathode plane on the other side has pads for triggering. The position of each strip must be known with an accuracy of 30 µm along the precision coordinate and 80 µm along the beam. The mechanical precision is a key point and must be controlled and monitored all along the process of construction and integration. The sTGC detectors are currently being produced and tested in five countries and assembled into wedges at CERN for integration into ATLAS. The sTGC design, performance, construction and integration status will be discussed, along with results from tests of the chambers with nearly final electronics with beams and cosmic rays.

        Speaker: Jesse Alan Heilman (Carleton University (CA))
      • 137
        Upgrade of the CMS muon spectrometer in the forward region with the GEM technology

        The Large Hadron Collider (LHC) will be upgraded in several phases that will allow to significantly expand its physics program and sustain the requirements to maintain sensitivity for the electroweak and TeV scales. After the expected long shutdown in 2018 (LS2) the accelerator luminosity will be increased to 2 − 3 × 10^34cm−2s−1 exceeding the design value of 1 × 10^34cm−2s−1 allowing the CMS experiment to collect approximately 100 fb−1/year. A subsequent upgrade in 2022-23 will increase the luminosity up to 5 × 10^34cm−2s−1.

        To cope with the corresponding increase in background rates and trigger efficiency requirements, the installation of additional muon detectors is a necessity. Three major upgrades are planned for the CMS muon endcap regions, referred to as GE1/1, GE2/1 and ME0. Each of the additional set of detectors is based on the Gas Electron Multiplier (GEM) technology, a choice based on many past R&D activities. While the installation of the GE1/1 chambers has been already approved and scheduled by 2019/20, the GE2/1 project is in an advanced phase of design and the ME0 project is now in the final phase of review.

        We present an overview of the muon spectrometer upgrade based on GEM technology, the details of the ongoing GE1/1 chamber production with the first results of the quality assurance tests. Moreover, preliminary results obtained for the GE2/1 single module M4 will be shown along with the design and the technical solution adopted for the foreseen GE2/1 and ME0 chambers.

        Speaker: Marek Michal Gruchala (Ghent University (BE))
      • 138
        Results of quality control of large size GEM detector based on Korean GEM foil for future upgrades of the CMS muon system

        GEM detectors have been developed for the Phase II upgrade and will be installed in the endcap stations of the CMS muon system. In detail, the detector station called GE1/1 will be installed during long shutdown 2 scheduled in 2019 and the other detector stations, called GE2/1 and ME0, later. This upgrade will improve the muon trigger and tracking performance in the high-eta region. The Korea CMS group and Mecaro, a company in Korea, have developed large GEM foils using a double-mask technique. Compared to the single-mask technique used so far, the production process is more simple and the more symmetric shape of the GEM holes improves the amplification process. We have built the first GEM chamber with such foils in double-mask technique and present results of several quality control tests on this GEM chamber.

        Speaker: Inseok Yoon (Seoul National University (KR))
      • 139
        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: Christos Bakalis (National Technical Univ. of Athens (GR))
      • 140
        Fast timing measurement for CMS RPC Phase II upgrade

        With the increase of the LHC luminosity foreseen in the coming years many detectors currently used in the different LHC experiments will be dramatically impacted and some need to be replaced. The new ones should be capable not only to support the high particle rate but also to provide time information to reduce the data ambiguity due to the expected high pileup.

        RPC using low-resistivity Bakelite are proposed to equip the very forward region of the CMS detector. In their single-gap version they can stand rates of few kHz/cm2. New electronics equipped with excellent timing precision measurement (<150ps) are being developed to read out the RPC detectors from both side of the strips to allow good spatial resolution along them. The absolute time measurement, determined by RPC signal (around 1 ns) will also reduce the data ambiguity due to the highly expected pileup at the Level 1 trigger and help to identify Heavy Scalar Charged Particles (HSCP).

        Principle of the measurement, implementation in front-end electronic boards (Petiroc front-end ASIC, wave-union TDC and PCB design) will be discussed. First results from cosmic tests and test beams at Gamma Irradiation Facility (GIF) and SPS at CERN would also be presented.

        Speaker: Maxime Gouzevitch (Centre National de la Recherche Scientifique (FR))
    • Higgs Physics: 3 105 (COEX, Seoul)


      COEX, Seoul

      Conveners: Samira Hassani (Université Paris-Saclay (FR)) , KOJI TSUMURA (Kyoto University)
      • 141
        Search for rare decays of the Higgs boson

        The Standard Model predicts decay channels of the Higgs boson that are rare and have not yet been seen. Searches for Higgs boson decays to two muons or to a Z boson and a photon based on pp collision data collected at 13 TeV are presented.

        Speaker: Haifeng Li (Shandong)
      • 142
        Searches of Higgs boson rare decays at CMS

        The latest results on searches of Higgs boson rare decays will be presented. The talk includes H to \mu\mu and H to invisible analyses.

        Speaker: Dr Raffaele Angelo Gerosa (Univ. of California San Diego (US))
      • 143
        Searches for non-Standard Model decays to a light meson and a photon of the Higgs boson

        Theories beyond the Standard Model predict Higgs boson decays at a much enhanced rate compared to the Standard Model, e.g. for decays to Z+photon or a meson and a photon. This talk presents recent results based pp collision data collected at 13 TeV.

        Speaker: Andrew Chisholm (CERN)
      • 144
        Searches for light Higgs bosons at CMS

        The searches for light pseudoscalar Higgs bosons pair produced from the decay of the 125 GeV Higgs boson and resulting in various final states (4mu, 4tau, 2mu2tau, 2b2tau) and low mass Higgs bosons will be summarised. The analyses are performed using data collected with the CMS experiment at the LHC from pp collisions at centre-of-mass energies of 13 TeV.

        Speaker: Somnath Choudhury (Indian Institute of Science (IN))
      • 145
        Searches for non-Standard Model decays to two light bosons of the Higgs boson

        Theories beyond the Standard Model predict Higgs boson decays that do not exist in the Standard Model, such as decays into two light bosons (a). This talk presents recent results based on pp collision data collected at 13 TeV.

        Speaker: Ariel Gustavo Schwartzman (SLAC National Accelerator Laboratory (US))
      • 146
        Searches for charged Higgs bosons at CMS

        An overview of the latest results on the charged Higgs boson searches by the CMS collaboration is presented. Different production mechanisms, as well as multiple final states (e.g. tau nu, tb and cb) are covered, as different BSM models predict different dominant production and decay modes. Most of the results presented are based on the dataset of proton-proton collisions at center of mass energy 13TeV, collected with the CMS detector in 2016, corresponding to an integrated luminosity of 36 fb^{-1}.

        Speaker: Santeri Henrikki Laurila (Helsinki Institute of Physics (FI))
      • 147
        Searches for additional charged Higgs bosons in the MSSM

        The MSSM predicts the existence of additional neutral and charged Higgs bosons. This presentation will discuss results from recent searches for charged Higgs bosons in several decay channels based on collision data collected at 13 TeV, and their interpretation within the MSSM.

        Speaker: Lluisa-Maria Mir (Barcelona)
    • Neutrino Physics: Reactor 103 (COEX, Seoul)


      COEX, Seoul

      Convener: Sunny Seo
      • 148
        New results from RENO

        The Reactor Experiment for Neutrino Oscillation (RENO) has been taking reactor antineutrinos data from the six reactors at Hanbit Nuclear Power Plant in Korea using two identical near and far detectors since August, 2011. The samllest neutrino mixing angle θ_13 has been successfully measured by observing the disappearance of reactor antineutrinos. In 2016, RENO has published an updated value of θ_13 and its first measurement of dm^2_ee based on energy dependent disappearance probability using 500 live days of data taken until January. RENO has accumulated more data to obtain more precise values of θ_13 and dm^2_ee. A study has been on progress to find changes in the observed reactor antineutrino flux with respect to the reactor fuel evolution. In this talk, we present newly measured values of θ_13 and dm^2_ee and results on the evolution of observed reactor antineutrino yields.

        Speakers: Dr Hyunkwan Seo, Hyunkwan Seo (Sungkyunkwan University (KR))
      • 149
        Latest Reactor Antineutrino Oscillation Results from the Daya Bay

        The Daya Bay experiment is designed to precisely measure the reactor electron-antineutrino oscillation utilizing eight functionally identical detectors placed at three underground experiment halls. The antineutrinos are generated from six reactor cores distributed with baselines from 500 m to 1600 m. In 2012, the Daya Bay experiment observed the reactor antineutrino disappearance and presented a measurement of $\sin^22\theta_{13}$ with a significance better than 5$\sigma$. Later in 2014, the collaboration reported an effective mass-squared difference $|\Delta m^2_{ee}|$. The Daya Bay collaboration are continuously improving the precision of $\sin^22\theta_{13}$ and $|\Delta m^2_{ee}|$ with higher statistics and better systematic uncertainties. In this talk, I will report the latest oscillation results of $\sin^22\theta_{13}$ and $|\Delta m^2_{ee}|$ with the neutron-gadolinium capture data sample and the results from another independent oscillation study with the neutron-hydrogen capture.

        Speaker: Dr Liang Zhan (Institute of High Energy Physics)
      • 150
        The measurement of absolute reactor neutrino flux and spectrum, and their evolution at Daya Bay

        The Daya Bay Reactor Neutrino Experiment consists of eight functionally identical detectors placed underground at different baselines from six 2.9 $\mathrm{GW_{th}}$ reactor cores. Since Dec. 2011, the experiment has collected more than 2.2 million inverse beta decay (IBD) candidates to date, enabling a precision measurement of the absolute reactor antineutrino flux and spectrum, and their fuel-dependent evolution. The comparison between measured spectrum and predictions from Huber-Mueller model revealed a 2.9 $\sigma$ deviation for the whole energy region and mostly pronounced in the region around 4-6 MeV. The measurement of the evolution of the reactor antineutrino flux and spectrum showed a 2.8 $\sigma$ discrepancy in the antineutrino flux variation with respect to the reactor fuel composition. The discrepancy suggests an overestimation of the predicted contribution from the $^{235}U$ fission isotope and indicates that this isotope could be primary contributor to the reactor antineutrino anomaly.

        Speaker: Dr Bei-Zhen Hu (National Taiwan University (on behalf of Daya Bay Collaboration))
      • 151
        Searching for a Light Sterile Neutrino at Daya Bay

        Additional generations of neutrinos that do not participate in standard V-A interactions - hence called “sterile” - arise in many extensions of the Standard Model. The existence of light sterile neutrino, with masses at eV or sub-eV scale, could explain several anomalies in short neutrino oscillation experiments as well as discrepancy in cosmological measurements of the Hubble parameter. I will report a search for light sterile neutrino mixing in the electron antineutrino disappearance channel by the Daya Bay Reactor Neutrino Experiment in the $2x10^{-4}$ ≲ $|\Delta m^2_{41}|$ ≲ 0.3 eV$^2$ range. The resulting limits on $sin^2 2θ_{14}$ constitute the most stringent constraints to date in the
        $|\Delta m^2_{41}|$ ≲ 0.2 eV$^2$ region. A joint analysis with electron antineutrino disappearance measurements from the Daya Bay and Bugey-3 experiments and the measurement of muon (anti)neutrino disappearance by the MINOS experiment will also be presented. The combined results place stringent constraints on electron neutrino and antineutrino appearance driven by sterile neutrino. The sterile-neutrino mixing parameter space allowed by the LSND and MiniBooNE experiments is excluded for $\Delta m^2_{41}$ < 0.8 eV$^2$ at 95% CLs.

        Speaker: Prof. Ming-chung Chu (The Chinese University of Hong Kong)
      • 152
        JUNO: A Multipurpose Underground Precision Neutrino Detector

        The Jiangmen Underground Neutrino Observatory (JUNO) is a reactor-based neutrino oscillation experiment primarily aiming at resolving neutrino mass hierarchy (MH) located in South China. There are a few key elements in designing the JUNO detector in order to resolve the neutrino mass hierarchy with high confidence levels. To get sufficient statistics within a reasonable amount of time, JUNO has designed a 20 kilo-tone liquid scintillator detector with an active veto system with good tracking capability; To maximize the hidden MH signal from the multiple reactor cores, the experiment site has been carefully chosen to be at ~53 km so various baselines differ less than 0.5 km; The two key elements in the JUNO central detector’s performance are its unprecedented energy resolution, 3%/sqrt(E/MeV), and its high precision absolute energy scale calibration uncertainty, better than 1%, for a LS detector. Such an unprecedented LS detector naturally provides the experiment the ability of measuring \Delta m^2_31 to sub-percent precision. Furthermore, due to its optimized baseline for the solar mass-squared splitting, JUNO is also capable of measuring the solar neutrino mixing parameters sin^2 2\theta12 and \Delta m^2_21 to sub-percent precision. This talk will present the physics potential of the JUNO experiment in resolving neutrino mass hierarchy, measuring oscillation parameters to unprecedented precision, detecting extra-terrestrial neutrinos and searching for other exotic physics.

        Speakers: Qingmin Zhang (Xi'an Jiaotong University) , Qingmin Zhang (Xi'an Jiaotong University)
      • 153
        Analysis of Gd(n,gamma) reaction with 155, 157 and natural Gd targets taken with JPARC-ANNRI and development of Gd(n,gamma) decay model for Gd-doped neutron/neutrino detectors

        The importance of a good model for the $\gamma$-ray energy spectrum from the radiative thermal neutron capture on Gadolinium (Gd) is specially increased in the present era of Gd-enhanced $\bar{\nu}_e$-search detectors. Its an essential prerequisite for MC studies to evaluate the neutron tagging efficiency, in order to enhance signal sensitivity in the Gd-loaded $\bar{\nu}_e$-search detectors.
        The $\gamma$-ray spectra produced from the thermal neutron capture on enriched gadolinium targets ($^{\rm 155}$Gd, $^{\rm 157}$Gd and Natural Gd) in the energy range 0.11 MeV to 8.0 MeV, were measured using the ANNRI Germanium Spectrometer at MLF, J-PARC [1, 2, 3]. Based on the data acquired and a GEANT4 simulation of the ANNRI detector, we reported the energy spectrum of $^{\rm 157}$Gd(n, $\gamma$) and
        developed a $\gamma$-ray emission model of $^{\rm 157}$Gd(n, $\gamma$) in our previous publication [1].
        We now present the analysed data of $^{\rm 155}$Gd(n, $\gamma$) and $^{\rm nat}$Gd(n, $\gamma$) reactions, the energy spectra of $\gamma$-rays and an improved model for $^{\rm 155}$Gd(n, $\gamma$), $^{\rm 157}$Gd(n, $\gamma$) and $^{\rm nat}$Gd(n, $\gamma$) reactions. The consistency of the results from the devised model is checked among all the 14 germanium crystals, at the level of 15% spectral shape deviation at 0.2 MeV binning.

        Speaker: Ajmi Ali
      • 154
        NSI @LBL

        I will describe nonstandard matter effects in the next generation long-baseline experiments, DUNE, T2HK and T2HKK.

        Speaker: Danny Marfatia (University of Hawaii)
    • Quark and Lepton Flavor Physics: 3 102 (COEX, Seoul)


      COEX, Seoul

      Convener: Margarida Nesbitt Rebelo (Instituto Superior Tecnico (IST))
      • 155
        Electroweak Penguin Decays at LHCb

        Rare b->sll decays are flavour changing neutral current processes that are forbidden at the lowest perturbative order in the Standard Model (SM). As a consequence, new particles in SM extensions can significantly affect the branching fractions of these decays and their angular distributions. The LHCb experiment is ideally suited for the analysis of these decays due to its high trigger efficiency, as well as excellent tracking and particle identification performance. Recent results from the LHCb experiment in the area of b->sll decays are presented and their interpretation is discussed.

        Speaker: Thomas Blake (University of Warwick)
      • 156
        Search for the rare decay $B \to \Lambda \bar{p} \nu \bar{\nu}$

        We search for the rare flavor-changing neutral current process $B^- \to \Lambda \bar{p} \nu \bar{\nu}$ using data from the BABAR experiment. A total of 424fb$^{−1}$ of $e^+e^−$ collision data collected at the center-of-mass energy of the $\Upsilon(4S)$ resonance is used in this study, corresponding to a sample of $(471\pm3)\times 10^6$ $B-\bar{B}$ pairs. Signal $B^- \to \Lambda \bar{p} \nu \bar{nu}$ candidates are identified by first exclusively reconstructing a $B^+$ decay in one of many possible decays to hadronic final states, then examining detector activity that is not associated with this reconstructed $B^-$ decay for evidence of a signal decay. The data yield is found to be consistent with the expected background contribution under a null signal hypothesis, resulting in an estimated branching fraction of $\cal{B}(B^-\to\Lambda\bar{p}\nu\bar{\nu}) = (0.4\pm1.1\pm0.6)\times10^{−5}$, where the uncertainties are statistical and systematic, respectively. An upper limit of $\cal{B}(B^-\to\Lambda\bar{p}\nu\bar{\nu}) < 3.0\times10^{−5}$ at the $90\%$ confidence level is determined.

        Speaker: Robert Seddon (McGill University)
      • 157
        Connecting b→sμμ anomalies to enhanced rare nonleptonic B_s decays in Z' model

        The anomalies recently observed in bsμμ data could be early signals of physics beyond the standard model (SM) in bs transitions. Assuming this to be the case, we consider a scenario in which a Z' boson is responsible for the anomalies. We further assume that its interactions also affect rare nonleptonic decays of the Bs meson which tend to be dominated by electroweak-penguin contributions and are purely isospin-violating. Most of these Bs decays are not yet observed, and their rates are expected to be relatively small in the SM. Taking into account various constraints, we find that the Z' effects can enhance the rates of some of these decays, particularly Bsηπ, ϕπ, by up to an order of magnitude. This Z' scenario is therefore potentially testable in upcoming experiments at LHCb and Belle II.

        Speaker: Dr Jusak Tandean (National Taiwan University)
      • 158
        Towards establishing New Physics in $B^0 \to K^{*0} \ell^+ \ell^-$ decays

        Rare semileptonic $b \to s \ell^+ \ell^-$ transitions provide some of the most promising framework to search for New Physics effects.
        Recent analyses have indicated an anomalous pattern in measurements of lepton-flavour-universality observables.
        We propose a novel approach to independently and complementary clarify the nature of these effects
        by performing a simultaneous amplitude analysis of $B^0 \to K^{*0} \mu^+\mu^-$ and $B^0 \to K^{*0} e^+e^-$ decays.
        This method allows the direct determination of the difference of the Wilson Coefficients ${\cal{C}}_{9}$ and ${\cal{C}}_{10}$ between electrons and muons,
        and are found to be insensitive to both local and non-local hadronic contributions.
        We show that considering the current preferred New Physics scenario a first observation of LFU breaking in a single measurement is possible with LHCb Run-II dataset.

        Speaker: Andrea Mauri (Zurich University)
      • 159
        Tests of lepton universality with semitauonic b-quark decays

        In the Standard Model, the three charged leptons are identical copies of each other, apart from mass differences. Experimental tests of this feature in semileptonic decays of b-hadrons are highly sensitive to New Physics particles which preferentially couple to the 2nd and 3rd generations of leptons. This talk will review the latest lepton universality tests in semileptonic b->c transitions at LHCb.

        Speaker: Olivier Leroy (Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France)
    • Strong Interactions and Hadron Physics: 3 101 (COEX, Seoul)


      COEX, Seoul

      Convener: Sungtae Cho (Kangwon National University)
      • 160
        Measurement of Bs and Y(5S) Decays with Belle

        The branching fraction of the decay Bs → Ds X has been measured by Belle and other experiments, but with indirect methods which have model-dependent limitations. We report a direct measurement of this decay by tagging one Bs from Y(5S) with semi-leptonic decay (Bs → Ds l nu), where several Ds decay modes are combined to increase the total statics. We also report a search for eta and eta' transitions from Y(5S) resonance to the lower bottomonia. These results are based on data sample of 121 /fb collected at the Y(5S) resonance by the Belle detector at the KEKB asymmetric-energy e+ e- collider. Other analyses on Bs and Y(5S) decays are also covered in this talk.

        Speaker: Leo Piilonen (Virginia Tech)
      • 161
        Observation of Y(4S) → eta’ Y(1S) and Y(2S) → gamma eta_b(1S) at Belle

        The hadronic transitions involving an eta meson, thoroughly studied by Belle, are the largest transitions from Y(4S) to the narrow bottomonia. The transition Υ(4S)→η′Υ(1S) yields insights on the quark content of the pseudoscalar mesons, and on the mechanism of heavy quark spin symmetry breaking, if compared with the eta transitions, We report the first observation of this transition, with the Y(1S) decay in a mu+mu- pair and the eta' decay in rho gamma or pi+pi-eta decay modes. The analysis is based on 497 /fb data collected on Y(4S) peak by Belle at the KEKB e+ e- collider. We also report on search for Y(2S) → gamma eta_b(1S) decay based on analysis of the inclusive photon spectrum of 24.7 fb^-1 of e+e- collisions at the Y(2S) center-of-mass energy with Belle. This result represents the first significant observation of this decay mode, and provides a new measurement of the eta_b(1S) mass and the branching fraction for this suppressed M1 transition. We also cover other measurements on bottomonia.

        Speaker: Bryan FULSOM (Pacific Northwest National Laboratory)
      • 162
        Study of radiative decays of the $\Upsilon(1S)$ and of three-body decays of the $J/\psi$

        We report on recent studies of quarkonium decays performed with the data collected by the BaBar experiment at the PEP-II $e^+e^-$ collider.
        In particular, we use the entire BaBar dataset to study the reaction $e^+ e^- \to \gamma_{ISR} J/\psi$, with $J/\psi \to \pi^+ \pi^- \pi^0$, $J/\psi \to K^+ K^- \pi^0$, or $J/\psi \to K_S K^\pm \pi^\mp$, and the photon $\gamma_{ISR}$ is produced via Initial-State-Radiation. We measure the relative $J/\psi$ branching fractions and perform a Dalitz plot analysis of each $J/\psi$ decay mode using an isobar model and a Veneziano model.
        We also present a study of the radiative decays of the $\Upsilon(1S)$ to $\pi^+\pi^-\gamma$ and $K^+K^-\gamma$ final states, performed on the data samples collected at the peak of the $\Upsilon(2S)$ and $\Upsilon(3S)$ resonances. The $\Upsilon(1S)$ is reconstructed from the decay chains $\Upsilon(nS) \to \pi^+\pi^-\Upsilon(1S)$, with $n=2,3$. Branching fractions measurements and spin-parity analysis are reported for the $\Upsilon(1S)$ radiative decays to intermediate resonances observed in the $\pi^+\pi^-$ and $K^+K^-$ mass spectra.

        Speaker: Nicolas Arnaud (LAL (CNRS/IN2P3 and Université Paris-Sud))
      • 163
        Studies of Bc mesons at LHCb

        The Bc meson, the heaviest amongst known meson, decays through the weak interaction. Its double heavy quark content make it an interesting laboratory for test of effective theories of the strong interaction with a unique setting for production, decay and spectroscopy studies. This talk presents recent progress on Bc decays obtained at LHCb.

        Speaker: Jibo He (University of Chinese Academy of Sciences (CN))
      • 164
        Measurement of beauty production from dimuon events at HERA

        Beauty production in events containing two muons in the final state has been measured with the ZEUS detector at HERA II. A low transverse-momentum threshold for muon identification, in combination with the large rapidity coverage of the ZEUS muon system and the upgraded ZEUS tracker, gives access to almost the full phase space for beauty production. The total cross section for beauty production in $ep$ collisions at $\sqrt{s}= 318$ GeV has been measured. Differential cross sections and a measurement of $b\bar{b}$ correlations are also obtained. All are compared to previous beauty cross-section measurements, Monte Carlo models and next-to-leading-order QCD predictions. The previous ZEUS measurements are confirmed with higher precision.

        Speaker: Peter John Bussey (University of Glasgow (GB))
      • 165
        Search for the $B$-meson decay to four baryons $B \to p \bar{p} p \bar{p}$

        $B$ mesons are the lightest mesons which can decay to various final states containing different baryons. Up to now, the discrepancy between the inclusive branching fraction of all $B$ meson decay modes with at least a couple of baryons in the final state, measured by ARGUS to be $(6.8 \pm 0.6)\%$ , and the sum of exclusive baryonic channels, averaged on neutral and charged $B$ mesons at less than $1\%$, represents an open issue. The measurement and comparison of exclusive branching fractions of baryonic $B$ decays, as well as studies on the dynamic of the decay, may allow better understanding of baryon production in $B$ decays and, more generally, hadron fragmentation into baryons. We present here a search for the decay $B \to p \bar{p} p \bar{p}$, not yet observed, by using a data set consisting of about 470 million $B-\bar{B}$ pairs collected with the BABAR detector at the SLAC National Accelerator Laboratory. We select $11.1 \pm 4.6$ candidate events, corresponding to a signal significance of $2.9\sigma$, and obtain
        the branching fraction of $(1.14\pm0.047(stat)\pm0.17(syst))\times10^{-7}$.

        Speaker: Laura Zani (INFN - National Institute for Nuclear Physics)
      • 166
        Heavy quark(onia) spectroscopy at LHCb

        The spectroscopy of excited hadronic states in the beauty sector, double heavy hadrons and quarkonia provides a rich proofing ground for effective theories of the strong interaction. The unique data set collected during runs 1 and 2 of the LHC have lead to the observation of several new states, interesting decay modes and has enabled precision mass measurements of known resonances. Here we present recent results from LHCb.

        Speaker: Daniel Johnson (CERN)
    • 4:00 PM
      Coffee break
    • Quark and Lepton Flavor Physics: 4 102 (COEX, Seoul)


      COEX, Seoul

      Convener: Olivier Leroy (Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France)
      • 167
        Studies of the CKM matrix with semileptonic decays

        Exclusive semileptonic b-hadron decays are under good theoretical control, which allows precise determinations of the CKM matrix elements, Vub and Vcb. The large production of Lambda_b baryons and Bs mesons at the LHC allows LHCb to provide complementary information with respect to the B-factories in this sector, as well as in the measurement of the shape of the Lambda_b differential decay rates. An alternative approach for measuring Vub, less affected by theoretical uncertainties, is through fully leptonic decay modes. Also this approach is explored at LHCb with the search for the B+->3munu decay. At the same time, novel experimental techniques are used to measure the fraction of semileptonic B+ to charm meson decays, in order to improve the understanding of the inclusive charm semileptonic rate and the background description for analyses exploiting exclusive b -> c and b->u transitions. The latest LHCb results on CKM matrix element determination and related measurements and searches are presented.

        Speaker: Ricardo Vazquez Gomez (CERN)
      • 168
        Determination of the CKM matrix elements $|V_{ub}|$ and $|V_{cb}|$ at Belle II

        The Belle II experiment is a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric $e^+ e^-$ collider. The accelerator has already successfully completed the first phase of commissioning in 2016 and first electron positron collisions in Belle II are expected for April 2018. The design luminosity of SuperKEKB 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 the Belle experiment. In this presentation we report our prospects for CKM favoured and suppressed semileptonic $B$ meson decays (with a light lepton) and how they can be used to better understand the CKM matrix element magnitudes $|V_{ub}|$ and $|V_{cb}|$.

        Speaker: Thomas Lueck (INFN - National Institute for Nuclear Physics)
      • 169
        Measurements of heavy flavor properties at CMS

        Recent measurements of the properties of heavy flavor particles at CMS, based on data collected at Run 1 and Run 2 of the LHC, are presented. Reported results include, among the others, measurements of lifetimes, masses and branching ratios of B hadrons and heavy quarkonia.

        Speaker: Po-Hsun Chen (National Taiwan University (TW))
      • 170
        B meson mixing parameters and branching fractions at LHCb

        New LHCb results in the measurement of B meson mixing parameters and branching fractions will be presented. The results are obtained using pp collisions collected in Run 1 and Run 2 of the LHC and include a new and world's most precise determination of the decay width difference in the Bs system and the ratio between the decay width of the Bs and Bd mesons.

        Speaker: Veronika Georgieva Chobanova (Universidade de Santiago de Compostela (ES))
    • Accelerators: Physics, Performance, and R&D for Future Facilities: Facilities 205 (COEX, Seoul)


      COEX, Seoul

      Convener: Daniel Schulte (CERN)
      • 171
        Status of SuperKEKB phase-2 commissioning

        SuperKEKB is 7GeV electron and 4GeV positron double-ring collider for the B-meson factory, whose design luminosity is $8 \times 10^{35} \mbox{cm}^{-2}/\mbox{sec}$. We have already completed the phase-1 commissioning without the interaction point from February 2 to June 28, 2016. The phase-2 commissioning with the interaction point is planed to start from March 19, 2018. We report the preliminary result of the SuperKEKB phase-2 commissioning.

        Speakers: Akio Morita for SuperKEKB commissioning team (KEK) , Akio Morita (High Energy Accelerator Research Organization (KEK))
      • 172
        First Muon RF Acceleration for the Muon g-2 Experiment at J-PARC

        The J-PARC E34 experiment aims to measure muon g-2 with a precision of 0.1 ppm and search for EDM with a sensitivity to 10-21 e*cm with a low emittance muon beam. The low emittance muon beam is generated from surface muon beam after thermal muonium production, dissociation of electron by laser, and acceleration by a radio-frequency (RF) linac. One of challenges for the E34 experiment is muon RF acceleration, which has not been demonstrated. Recently we succeeded in demonstrating muon acceleration using a radio-frequency quadrupole linac (RFQ). This talk will describe results of the muon acceleration experiment.

        Speaker: Dr Masashi Otani (KEK)
      • 173
        Fermilab Accelerator Complex: Status, Progress, and Near-and Far- Future Upgrade Plans

        We present status of operation and recent progress of the Fermilab proton accelerators, and discuss in our activities toward their near- and far-future upgrades. We also present the spectrum of related accelerator physics and technology R&D activities, including those at the US-leading FAST/IOTA research facility for the intensity frontier beam studies.

        Speaker: Phil Adamson (Fermi National Accelerator Laboratory)
      • 174
        LBNF Beamline

        The Long Baseline Neutrino Facility (LBNF) will utilize a beamline located at Fermilab to provide and aim a neutrino beam of sufficient intensity and appropriate energy range toward DUNE detectors, placed deep underground at the Sanford Underground Research Facility (SURF) in South Dakota. LBNF is designed for approximately twenty years of operation, to provide adequate exposure for the DUNE experiment. During its lifetime, the facility must be able to accommodate various target and focusing configurations to enable tuning of the neutrino energy spectrum.

        The primary proton beam (60-120 GeV) will be extracted from the MI-10 section of Fermilab's Main Injector. Neutrinos are produced after the protons hit a solid target and produce mesons, which are subsequently focused by magnetic horns into a 194m long decay pipe where they decay into muons and neutrinos. The parameters of the facility were determined by taking into account the physics goals, spatial and radiological constraints and the experience gained by operating the NuMI facility at Fermilab. The Beamline facility is designed for initial operation at a proton-beam power of 1.2 MW, with the capability to support an upgrade to about 2.4 MW. LBNF/DUNE obtained CD-1 approval in November 2015. We discuss here the design status and the associated challenges as well as the R&D and plans for improvements before baselining the facility, and we will present results of a beam optimization algorithm developed to maximize DUNE's sensitivity to neutrino CP violation, yielding substantial improvements to the neutrino flux and physics sensitivities.

        Speakers: Heidi Marie Schellman (Oregon State University (US)) , Mr Schellman Heidi
      • 175
        Status of the Fermilab Muon g-2 experiment

        Previous Muon g-2 experiment at BNL measured the anomalous magnetic moment of muon which is $\approx 3 \sigma$ away from the Standard Model value. The Fermilab Muon g-2 Collaboration started commissioning runs with an upgraded version of the storage ring. In the first phase, the new experiment aims 4 times more sensitivity thanks to several improvements including muons statistics, pileup reduction, gain changes, lost muons and coherent betatron oscillations. A physics run with significant statistics is expected to take place in 2018.

        Speaker: Dr Selcuk Haciomeroglu (CAPP/IBS)
    • Astro-particle Physics and Cosmology: 4 104 (COEX, Seoul)


      COEX, Seoul

      Convener: Andrei Kounine (Massachusetts Inst. of Technology (US))
      • 176
        Highlights from the Telescope Array Experiment

        Telescope Array (TA) is the largest cosmic ray detector in the Northern hemisphere, constructed to study ultra high energy cosmic rays (UHECRs) with energies above 10^18 eV. The TA consists of an array of scintillation counters with 1200 m spacing and three fluorescence detectors, each viewing 3 to 30 degrees in elevation. The TA has also added a facility (TALE) to extend the energy threshold down to 10^15.8 eV, by addition of 10 additional fluorescence telescopes increasing the elevation angle up to 59 degrees, and an infill array of plastic scintillation counters with spacing of 400 and 600 m. The TA has accumulated a large UHECR data set which allows us to determine the energy spectrum and chemical composition of the primary particles, and search for anisotropy of UHECR arrival directions and thus sources of cosmic rays. We discuss findings with the latest data about the localized excess of events known as the TA "hotspot". The experiment and its most recent measurements - spectrum, composition, and anisotropy - will be presented.

        Speaker: Prof. IL H. PARK (Sungkyunkwan University (SKKU))
      • 177
        Tests of hadronic interactions using the Pierre Auger Observatory

        Ultra-high energy cosmic rays (UHECR) can be used to study hadronic interactions beyond LHC energies. In this contribution we summarize relevant data from the Pierre Auger Observatory.

        While the proton-air cross section has been measured at sqrt(s) = 57 TeV and found to be in good agreement with extrapolations from LHC energies, other observables are significantly different to what is predicted using current models. In particular, the predictions from models of showers based on LHC data are in strong contradiction with the observed number of muons. More muons are detected than predicted with the magnitude of the effect being model-dependent. Another observable from the Auger Observatory, the distribution of the depths of muon production, is also poorly described. Indeed no current model is capable of describing the full range of data from the Observatory, thus highlighting deficiencies in extrapolations beyond LHC energies.

        The discrepancy between hadronic models can be examined further by measuring separately the muon and electromagnetic components of the signal recorded by detectors on the ground. The Auger Observatory is being upgraded by the addition of plastic scintillators above the water-Cherenkov detectors to achieve this. The new observations will enable rigorous testing of hadronic models up to sqrt(s) ~100 TeV and are crucial to the quest of determining the composition of UHECR.

        Speaker: Dr Patricia Hansen for the Pierre Auger Collaboration (IFLP (CCT La Plata-CONICET), Dpto. de Física, Fac. de Cs. Exactas y Dpto. de Cs. Básicas, Facultad de Ingeniería, Universidad Nacional de La Plata, C. C. 67 - 1900 La Plata, Argentina.)
      • 178
        The LHCf experiment: recent physics results

        The main aim of the LHC forward (LHCf) experiment [1] is to provide precise measurements of the particles production rate in the forward region. These high energy calibration data are very important for the tuning of hadronic interaction models used by ground-based cosmic rays experiments. LHC is the most suitable place where we can perform these measurements because a proton-proton collision at $\sqrt{s}$ = 14 TeV is equivalent to the interaction of a $10^{17}$ eV cosmic ray with the atmosphere. In order to do that, two small sampling calorimeters are installed at ±140 m from LHC IP1 (ATLAS Interaction Point), so that they can detect the neutral particles with $\eta$ > 8.4 produced in p-ion collisions [2].

        In the past years, LHCf acquired data from p-ion collisions at different energies (p-p at $\sqrt{s}$ = 0.9, 2.76, 7 and 13 TeV; p-Pb at $\sqrt{s_{NN}}$ = 5.02 and 8.1 TeV). In this talk, we would like to present the analysis results relative to photons [3], neutrons [4] and $\pi^{0}$ [5] differential production cross sections, compared with models predictions. In particular, we will discuss the measurement of the energy distributions of secondary particles produced in $\sqrt{s}$ = 13 TeV p-p collisions (photons, already published [6], and neutrons) and in $\sqrt{s_{NN}}$ = 8.1 TeV p-Pb collisions (photons). In all these cases, no model resulted to be in good agreement with experimental observations in all the regions investigated by the analysis. We will also discuss about the ATLAS-LHCf joint analysis, based on the common data taking that the two experiments had in the last two operations at LHC. This activity is very important because the information of the ATLAS detector in the central region is an useful tag to distinguish between diffractive and non-diffractive events in the LHCf detector. Finally, we will present the measurement relative to the contribution of diffractive dissociation to the production of forward photons in $\sqrt{s}$ = 13 TeV p-p collisions [7], the first result from the ATLAS-LHCf joint analysis.

        Speaker: Eugenio Berti (Universita e INFN, Firenze (IT))
      • 179
        The unusual structure detection in Extensive air shower events at Horizon-8T cosmic rays detector system

        Horizon-8T is a detector system aimed to study Extensive Air Showers (EAS) temporal structure in the energy range of the primary above ~10^16 eV. It is constructed at approximately 3340 meters above the sea level at the Tien Shan high-altitude Science Station, part of Lebedev Physical Institute of the Russian Academy of Sciences. Detector system consists of eight charged particle detection points separated by the distance up to one kilometer.
        During Physics Run 1 from October 2016 to April 2017, about 8000 total events were detected, a sizable number of which exhibit the unusual spatial and temporal structure of pulses with several maxima (or modes). The separation of the maxima can be from few tens of ns to several hundred ns. The Run 1 dataset suggests that separation between maxima increases with distance from EAS core, which cannot be obtained from simulations, and seem to occur only in events with energy above ~10^17 eV. The overview of Horizon-8T detector system and the details of the unusual events data will be presented.

        Speaker: Ayan Batyrkhanov
      • 180
        Constraining New Physics with high multiplicity

        Having no new physics signals observed at collider experiments, we are motivated to consider a scenario that the new physics scale is higher than the current collider energies but still within the reach of the cosmic ray experiments covering beyond TeV scale. In particular, we focus on the types of new physics interactions accompanying with high multiplicities in their signals from the collision of Ultra-High Energy (UHE) cosmic ray with nucleons in the Earth atmosphere with collision energy E > O(100) PeV or Ecm > O(10) TeV in center-of-mass (CM) frame. The characteristic features of neutrino-induced air-showers and proton-induced air-showers induced by new physics interactions are identified then the experimental constraints on the new physics scale are obtained from the existing and future coming data from Telescope-Array (TA) and Pierre-Auger experiments. As specific examples, we show the results from electroweak sphaleron and TeV scale microscopic black holes in detail.

        Speaker: Prof. Seong Chan Park (Yonsei University)
    • Beyond the Standard Model: 4 203 (COEX, Seoul)


      COEX, Seoul

      Convener: Myeonghun Park (SNUT)
      • 181
        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: Anyes Taffard (UCI)
      • 182
        Searches for 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 slepton pair production.

        Speakers: Dr Margherita Primavera (Lecce) , Margherita Primavera (INFN Lecce e Universita del Salento (IT)) , Margherita Primavera (Univ. + INFN)
      • 183
        Searches for electroweakly produced supersymmetry with CMS

        In supersymmetric models where colored sparticles are beyond the reach of the LHC, the electroweak production of SUSY particles may constitute the dominant SUSY processes that could be observed at the LHC. In this talk, I will discuss the results of CMS searches for electroweakinos and sleptons. These searches are challenging because of the low production cross sections, however the growing LHC dataset allows us to improve our sensitivity to these signal processes.

      • 184
        Dark Matter searches with the ATLAS Detector

        Dark matter could be produced at the LHC if it interacts weakly with the Standard Model. The search for dark matter can be performed either directly, by looking for a signature of large missing transverse momentum coming from the dark matter candidates escaping the detector, or more indirectly by looking for the intermediate mediators which would couple the dark matter particles to the Standard Model. A broad and systematic search program covering these various possibilities with the ATLAS detector is in place: the talk will review the latest results of these searches and show their complementarity.

        Speaker: Dr Emma Tolley (Ohio State U)
      • 185
        Searches for new physics in dijet and multijet final states

        Results of searches for new physics in the dijet and multijet final states are presented. These include model-independent and model-specific searches using the dijet invariant mass spectrum and the dijet angular distributions, searches for black holes, quantum and microscopic, in multijet events, as well as searches for RPV SUSY in events with paired dijets. This talk focuses on the recent results obtained using data collected at Run-II of the LHC.

        Speaker: Sung Won Lee (Texas Tech University (US))
      • 186
        Searches for New Phenomena in Dijet Events with the ATLAS Detector

        Events with two hadronic jets in the final state are of particular interest in the search for physics beyond the Standard Model: new phenomena produced in parton collisions are likely to produce final states with (at least) two partons. In this talk several searches performed by the ATLAS collaboration are presented. The very high mass and the low mass regions have both been investigated, by exploiting dedicated signatures and, in case of the latter, new techniques to overcome trigger limitations. Final states with b-jets have also been explored.

        Speakers: Dr Andrea Coccaro (Genova) , Andrea Coccaro (INFN Genova (IT))
      • 187
        Searches for new physics in lepton+jet final states

        Results of searches for new particles such as leptoquarks, heavy neutrinos, and W bosons with right-handed couplings in final states with leptons (charged or neutral) and jets are presented. The emphasis is given to the recent results obtained using data collected at Run-II of the LHC.

        Speaker: Muzamil Ahmad Bhat (Tata Inst. of Fundamental Research (IN))
      • 188
        Search for New Physics through the Reconstruction of Challenging Signatures with the ATLAS detector

        Many theories of beyond the Standard Model (BSM) physics predict unique signatures which are difficult to reconstruct and the background rates are also a challenge. Signatures from displaced vertices anywhere from the inner detector to the muon spectrometer as well as those of new particles with fractional or multiple value of the charge of the electron or high mass stable charged particles are experimentally demanding signatures. The results of searches using data collected by the ATLAS detector of √s = 13 TeV pp collision is presented.

        Speaker: Dr Marianna Testa (Frascati)
      • 189
        Monojet signatures at the High-Luminosity and High-Energy LHC

        In some class of BSM models, such as SUSY , DM may be searched using high pT jets + missing ET, where DM (X) may be
        produced from the decay of a heavy particle H. If mH is close to mX, the signature is ISR , and may be monojet like, and there are much
        information on the nature of H and X. I will discuss leading jet distribution contains the information of both mH, color representation
        and spin of the particles, but to extract the information fully, one need to predict the distribution with less than 10% accuracy
        for the parameter region that may be studied at HL-or HE-LHC. Then I turn into the theoretical error in the current best NLO MC
        based on MC@NLO scheme, such as MG5 and Sherpa, and discuss if such accuracy can be achieved.

        Speaker: Prof. Mihoko Nojiri (Theory Center, IPNS, KEK)
    • Computing and Data Handling: Machine Learning 2 / Trigger and DAQ 201 (COEX, Seoul)


      COEX, Seoul

      Conveners: Sang Un Ahn (Korea Institute of Science & Technology Information (KR)) , Doris Yangsoo Kim (Soongsil University)
      • 190
        Applying deep learning methods to HEP data

        We apply deep learning methods to various aspects of high energy physics problems, from jet reconstruction to top quark reconstruction at hadron colliders. Various supervised and unsupervised learning method use cases and failure cases are discussed. We describe our setup to make deep learning methods easier for users who are used to analyzing with ROOT data formats.

        Speaker: Su Yong Choi (Korea University (KR))
      • 191
        Automated Monitoring Tools for the CMS Muon System Based on Machine Learning Algorithms

        Monitoring the quality of the data being collected by the CMS Muon system to ensure that it fulfills the requirements needed to be used for physics analyses is a time-consuming and labor-intensive task. The CMS Muon group is developing a reliable and robust tool that will make use of automated statistical tests and modern machine learning algorithms to reduce the resources needed to run and monitor the muon sub-detectors. The challenge in the development of such a tool is that the running conditions of the LHC experiments are not static, causing the quantities used for data monitoring to evolve. Furthermore, the tool must be applicable to the monitoring of all four muon sub-detectors (Cathode Strip Chambers, Drift Tube chambers, Gas Electron Multiplier chambers, Resistive Plate Chambers), which all depend on different detector technologies and are located in different geometrical areas of the detector. We will present an overview of the current tools and workflows used for monitoring, together with the status of the state-of-the-art developments towards the automated monitoring that we will implement for the future LHC runs.

        Speaker: Junghwan Goh (Hanyang University (KR))
      • 192
        Machine Learning on Datacenter Operations

        Google said it has reduced electricity bills by introducing machine learning into its data center operations. And what else is there?

        Speaker: Jeongheon Kim (Korea Institute of Science and Technology Information)
      • 193
      • 194
        The LHCb Run 2 trigger as a benchmark for the upgrade

        The LHCb upgrade trigger represents a new paradigm in high energy physics: A fully software trigger operating at the LHC bunch crossing frequency with a triggerless readout. The existing level-0 hardware trigger in Run 2 has allowed us to test much of the upgrade strategy at 1MHz. In this talk, we will describe the performance of the Run 2 trigger in pp and special data taking configurations, and the implications for the deployment of the upgrade trigger at 30MHz.

        Speaker: Mark Peter Whitehead (Rheinisch Westfaelische Tech. Hoch. (DE))
      • 195
        CMS High Level Trigger performance at 13 TeV

        The CMS experiment selects events with a two-level trigger system: the Level-1 trigger (L1) and the High Level Trigger (HLT). The HLT is a farm made of approximately 30k CPU cores that reduces the rate from 100 kHz to about 1 kHz. The HLT has access to the full detector readout and runs a dedicated online event reconstruction to select events. In 2017, LHC instantaneous luminosity during standard operations was about $1.5 \cdot 10^{34} cm^{-2}s^{-1}$ with pile-up of 55, well above the design values, and it is expected to exceed $2.0 \cdot 10^{34} cm^{-2}s^{-1}$ in 2018 by increasing the number of proton bunches. In these conditions, the online event selection is very challenging.

        We present the most recent HLT performance results and the methods used at HLT to cope with a high pile-up environment.

        Speaker: Laurent Thomas (Universite Libre de Bruxelles (BE))
      • 196
        An Introduction of DAQ system for CUP experiments

        CUP, Center for Underground Physics, is one of the research centers belonging to Institute for Basic Science (IBS), Korea. CUP is conducting several experiments in the field of neutrinoless double beta decay, direct WIMP search, and neutrino oscillation, such as COSINE-100, AMoRE, and NEOS experiment. CUP has developed the DAQ system for these experiments including hardware and software. In this talk, DAQ system for CUP experiments is introduced focusing on electronics, online DAQ software, and monitoring system.

        Speaker: Dr Jaison Lee (CUP/IBS)
    • Detector: R&D for Present and Future Facilities: 4 202 (COEX, Seoul)


      COEX, Seoul

      Convener: Gobinda Majumder (Tata Inst. of Fundamental Research (IN))
      • 197
        Upgrade of the ATLAS Monitored Drift Tube Frontend Electronics for the HL-LHC

        To cope with large amount of data and high event rate expected from the planned High-Luminosity LHC (HL-LHC) upgrade, the present ATLAS monitored drift tube (MDT) readout electronics will be replaced. In addition, the MDT detector will be used at the first-level trigger to improve the muon transverse momentum resolution and reduce the overall trigger rate. A new trigger and readout system has been proposed. Prototypes for two frontend ASICs and a data transmission board have been designed and tested, and detailed simulation of the trigger latency has been performed. We will present the overall design and focus on latest results from different ASIC and board prototypes.

        Speaker: Oliver Kortner (Max-Planck-Institut fur Physik (DE))
      • 198
        The ATLAS trigger in 2017 and 2018 – developments and performance

        The ATLAS Trigger system has been operating successfully during LHC Run-2, between 2015 and 2017. Its excellent performance has been vital for the ATLAS physics program, selecting interesting collision events for a wide variety of physics signatures with high efficiency.

        The trigger selection capabilities of ATLAS during Run-2 have been significantly improved compared to Run-1, in order to cope with the higher event rates and with the large number of simultaneous proton-proton interactions (pile-up). At the Level-1 trigger these improvements resulted in more pile-up-robust selection efficiencies and event rates, as well as in a reduction of fake candidate particles. A new hardware system, designed to analyse event-topologies, supports a more refined event selection at Level-1. Exemplary are the application of angular and invariant mass cuts in low momentum di-lepton and di-jet triggers, keeping the Level-1 rate of such selections, which are essential for many physics analyses, at an affordable level. A hardware-based, high-rate track reconstruction, currently being commissioned, enables the high-level software trigger to make use of tracking information at its full input rate. Such full-scan tracking has an important role in reducing the pile-up dependence of triggers based on isolated single leptons and those selecting on total transverse energy. Together with an upgrade of the high-level trigger selections to deploy more offline-like reconstruction techniques, these changes dramatically improve the performance of the trigger selection to nearly that of the offline reconstruction.

        At the beginning of 2017 more than 1000 different ATLAS trigger selections had been carefully compiled into a “trigger menu”, covering all aspects of the ATLAS physics program and allowing for the expected rise in LHC luminosity. An unexpected change in the LHC conditions in the middle of 2017 toward an environment with much higher pile-up resulted in a much-increased CPU usage of the software trigger and reduced performance, requiring adaptation of the selection software and the general trigger menu design.

        This presentation gives a comprehensive review of the ATLAS trigger system in 2017, covering briefly the changes compared to 2016, operational aspects, and encountered constraints. The trigger menu strategy for 2018, the last year of Run-2 will be shown. Focus will be put on the new event-topology-based selections at the Level-1 trigger, and on the trigger performance at high pile-up seen in 2017. The improvement measures taken for 2018 will be discussed and substantiated with first 2018 trigger performance plots.

        Speaker: Daniele Zanzi (CERN)
      • 199
        Design and performance of the upgrade of the CMS L1 trigger

        During its second run of operation, the LHC delivered proton-proton collisions at a centre-of-mass energy of 13 TeV with a peak instantaneous luminosity larger than $2 \cdot 10^{34} cm^{-2}s^{-1}$, more than double the peak luminosity reached during Run1 and far larger than the design value. The upgraded CMS Level-1 trigger is designed to improve the performance at high luminosity and large number of simultaneous inelastic collisions per crossing (pile-up). During the technical stop at the beginning of 2016, all the electronic boards of the CMS Level-1 trigger have been replaced and the upgraded electronics tested, and commissioned with data. Smarter, more sophisticated, and innovative algorithms are now the core of the first decision layer of CMS: the upgraded trigger system implements pattern recognition and MVA (Boosted Decision Tree) regression techniques in the trigger boards for $\text{p}_{\text{T}}$ assignment, pile-up subtraction, and isolation requirements for electrons and taus. In addition, the new global trigger is capable of evaluating complex selection algorithms such as those involving the invariant mass of trigger objects. The upgrade reduces the trigger rate and improves the trigger efficiency for a wide variety of physics signals. In this presentation the upgraded CMS Level-1 trigger design and its performance are described.

        Speaker: Olivier Davignon (University of Bristol (GB))
      • 200
        Design of the CMS upgraded trigger from Phase I to Phase II of the LHC

        The CMS experiment implements a sophisticated two-level triggering system composed of the Level-1, instrumented by custom-design hardware boards, and the High Level Trigger, a streamlined version of the offline reconstruction software running on a computer farm (more than 30k CPU cores). In 2017, the LHC delivered proton-proton collisions at a centre-of-mass energy of 13 TeV with a peak instantaneous luminosity larger than $2 \cdot 10^{34} cm^{-2}s^{-1}$, more than twice the peak luminosity reached during Run1 and far larger than the design value. The CMS Level-1 trigger was upgraded during the end-of-the year technical stop between 2015 and 2016, to improve its performance at high luminosity and large number of simultaneous inelastic collisions per crossing (pile-up). All the electronic boards have been replaced and the upgraded electronics tested and commissioned with data. Smarter, more sophisticated, and innovative algorithms are now the core of the first decision layer of CMS: the upgraded trigger system implements pattern recognition and MVA (Boosted Decision Tree) regression techniques in the trigger boards for $\text{p}_{\text{T}}$ assignment, pile-up subtraction, and isolation requirements for electrons and tau leptons. In addition, the new global trigger is capable of evaluating complex selection algorithms such as those involving the invariant mass of trigger objects.
The High Level Trigger features a trade-off between the offline complexity of the algorithms and the available computing power, and between the selection efficiency the maximum sustainable output rate. The trigger selections used in Run-2 will be presented, ranging from simpler single-object selections to more sophisticated algorithms combining different objects and applying analysis-level reconstruction and selection. 
This presentation will cover the design and performance of the Phase I trigger and how it influences the path towards the Phase II upgrade necessary for the LHC run at a center-of mass energy of 14 TeV with luminosity of $5-7 \cdot 10^{34} cm^{-2}s^{-1}$, corresponding to 140--200 pile-up events. The addition of the tracker information at Level-1 and the enhanced computing resources at HLT will maintain the trigger efficiency at a similar level as the present one.

        Speaker: Silvio Donato (Universitaet Zuerich (CH))
      • 201
        ATLAS level-1 calorimeter trigger: Phase-I Upgrade Performance

        Following the Run 2 LHC data taking, the ATLAS experiment at CERN will enter the first phase (Phase-I) of the planned detector subsystem upgrades. Several systems, in particular, the hardware-based Level-1 calorimeter trigger (L1Calo) will be significantly enhanced to provide improved selectivity at the higher expected pileup in Run 3. During the second long shutdown (LS2) in 2019-2020, the existing L1Calo
        electronic processor modules will be replaced with new, advanced boards, called feature extractors, which will receive higher-granularity information from the calorimeters and will support the implementation of more sophisticated algorithms to select electrons or photons, jets, met and large-radius jets.

        This presentation will summarise the anticipated functionality of the upgraded L1Calo trigger system. In particular, the performance of the preliminary trigger-level algorithms and a comparison to the operation of the Run 2 L1Calo system will be described.

        Speaker: Chiao-Ying Lin (University of Cambridge (GB))
      • 202
        The ATLAS Muon Trigger

        Events containing muons in the final state are an important signature for many analyses being carried out at the Large Hadron Collider (LHC), including both standard model measurements and searches for new physics. To be able to study such events, it is required to have an efficient and well-understood muon trigger. The ATLAS muon trigger consists of a hardware based system (Level 1), as well as a software based reconstruction (High Level Trigger). Due to high luminosity and
        pile up conditions in Run 2, several improvements have been implemented to keep the trigger rate low while still maintaining a high efficiency. Some examples of recent improvements include requiring coincidence hits between different layers of the muon
        spectrometer, improvements for handling overlapping muons, and optimised muon isolation. We will present an overview of how we trigger on muons, recent improvements, and the performance of the muon trigger in Run-2 data.

        Speaker: Alexander Held (CERN)
      • 203
        Level-1 track finding with an all-FPGA system at CMS for the HL-LHC

        The CMS experiment at the LHC is designed to study a wide range of high energy physics phenomena. It employs a large all-silicon tracker within a 3.8 T magnetic solenoid, which allows precise measurements of transverse momentum (pT) and vertex position.

        This tracking detector will be upgraded to coincide with the installation of the High-Luminosity LHC, which will provide up to about 10^35 cm^2 /s to CMS, or 200 collisions per 25 ns bunch crossing. This new tracker must maintain the nominal physics performance in this more challenging environment. Novel tracking modules that utilise closely spaced silicon sensors to discriminate on track pT have been developed that would allow the readout of only hits compatible with pT > 2-3 GeV tracks to off-detector trigger electronics. This would allow the use of tracking information at the Level-1 trigger of the experiment, a requirement to keep the Level-1 triggering rate below the 750 kHz target, while maintaining physics sensitivity.

        This talk presents a concept for an all FPGA based track finder using a time-multiplexed architecture. Hardware demonstrators have been assembled to prove the feasibility and capability of such a system. The performance for a variety of physics scenarios will be presented, as well as the proposed scaling of the demonstrators to the final system and new technologies.

        Speaker: Thomas Owen James (Imperial College Sci., Tech. & Med. (GB))
      • 204
        Level1 Calorimeter Trigger: from Xilinx Virtex7 to Ultrascale+

        With the restart of the LHC in 2021 the ATLAS experiment will cope with high luminosity beams (2.5 x 10 34 cm -2 s -1 ). A new Level-1 Calorimeter trigger system (see Fig.1) will be introduced exploiting a finer calorimeter readout granularity. The new system consists of three Feature EXtractors (FEXs), electron (eFEX), jet (jFEX) and global (gFEX), that use FPGAs to reconstruct different physics objects used for the trigger selection and that gather data from the calorimeters through a Fibre Optical Plant. The Trigger Objects produced by the algorithms running on the FEXs are optically sent to the Level-1 Topological Trigger where interesting physics events are selected by applying kinematic and angular requirements on electromagnetic clusters, jets and total energy.

        This contribution will focus on the new jFEX system and on the upgrade of the L1Topological trigger giving an overview of the hardware as well as the algorithmic firmware.

        The jFEX (see Fig. 2) and the upgraded L1Topological Trigger are Ultrascale+ based ATCA boards that cope with input data rates of up to 3.6 Tb/s for a maximum of 120 Multi Giga Transceivers (MGTs) per FPGA. To achieve the high transmission speed and high component density for these boards, a number of challenges in power management, voltage distribution and signal integrity had to be addressed in the design.
        Figure 1 Figure 2

        The latest generation Ultrascale+ FPGAs provide large processing resources for sophisticated trigger algorithms. The jFEX will allow to reconstruct small- and large-area jets including high-granularity substructure observables. Energy from pile-up interactions can be determined on an event-by-event basis and subtracted for jets and MET. On the L1Topological Trigger, kinematic reconstruction of full events will be performed within 50ns, and even exotic triggers mixing information from different bunch crossings will be possible.

        This contribution will present the design, integrated tests programming of the jFEX and L1Topological Trigger modules.

        Speaker: Marcel Weirich (Johannes Gutenberg Universitaet Mainz (DE))
      • 205
        The ATLAS FastTracker: Pioneering the next era of hardware track triggers

        Though hardware-based trackers were a crucial element of the triggering systems for both D0 and CDF, no such system has yet been incorporated into either ATLAS or CMS. The ATLAS FastTracKer (FTK) is a first step towards this goal, and will soon provide full tracking information for all events passing ATLAS’s Level-1 trigger. This system massively reduces the CPU required to identify track-based signatures like b-jets and taus, and allows for the suppression of pile-up effects on missing energy and jet triggers. This talk will present an overview of FTK commissioning and future plans, along with updated projections for FTK performance.

        Speaker: Tova Ray Holmes (University of Chicago (US))
    • Higgs Physics: 4 105 (COEX, Seoul)


      COEX, Seoul

      Conveners: Samira Hassani (Université Paris-Saclay (FR)) , KOJI TSUMURA (Kyoto University)
      • 206
        Searches for additional neutral Higgs bosons in the MSSM

        The MSSM predicts the existence of additional neutral and charged Higgs bosons. This presentation will discuss results from recent searches for neutral Higgs bosons in several leptonic decay channels based on collision data collected at 13 TeV, and their interpretation within the MSSM.

        Speaker: Junichi Tanaka (Tokyo ICEPP)
      • 207
        Searches for extended Higgs boson sectors with CMS

        The latest results on searches of for extended Higgs boson sectors will be presented. MSSM Htautau, Hbb, high mass searches, and charged Higgs will be covered.

        Speaker: Chayanit Asawatangtrakuldee (Deutsches Elektronen-Synchrotron (DESY))
      • 208
        Searches for high-mass resonances

        Several theories beyond the Standard Model predict the existence of new heavy particles decaying into pairs of gauge bosons. In this presentation the latest ATLAS results on searches for resonances decaying into pairs of W or Z bosons or photons, or into a Z boson and a photon, based on 36 fb-1 of pp collision data collected at 13 TeV will be discussed.

        Speaker: Kirill Grevtsov (DESY)
      • 209
        Higgs to WW measurements with CMS

        The latest set of results on Higgs decay to a W boson pair is presented. With a statistics of 36/fb collected by the CMS experiment at the LHC at 13 TeV center of mass energy, the Higgs to WW decay has been observed at CMS with more than 5 sigma for the first time, providing a significant contribution to the current fit of the Higgs boson couplings to fermions and vector bosons. Exploiting the large cross section times branching ratio of this channel, and using 78/fb of data, differential distributions as a function of the Higgs boson transverse momentum and as a function of the number of jets produced in association have been measured. Finally a search for high mass scalar resonances decaying to W boson pairs is performed ranging up to 3 TeV of mass.

        Speaker: Lorenzo Viliani (Universita e INFN, Firenze (IT))
      • 210
        Measurement of cross sections and properties of the Higgs boson in decays to two W bosons using the ATLAS detector

        Measurements of Higgs boson properties and cross sections measured in Higgs boson decays to two W bosons based on pp collision data collected at 13 TeV are presented.

        Speaker: Dominik Duda (Munich MPI)
    • Neutrino Physics: Sterile (II) 103 (COEX, Seoul)


      COEX, Seoul

      Convener: Sunny Seo
      • 211
        The Short Baseline Neutrino Program at Fermilab

        The Fermilab Short-Baseline Neutrino (SBN) program, with three liquid argon time projection chamber (LAr-TPC) detectors located along the Booster Neutrino Beam, presents a rich physics and R&D opportunity. SBN will perform sensitive searches for neutrino oscillations in both appearance and disappearance channels at the 1 eV^2 mass- splitting scale, thereby testing the sterile neutrino interpretation of the anomalous excesses of electron (anti)neutrinos observed by LSND and MiniBooNE. Also, the SBN detectors play a major role in on-going R&D efforts aimed at realizing multi-kiloton-scale LAr-TPC detectors in the next generation long-baseline neutrino oscillation experiment DUNE. To form the SBN program, two additional detectors will join MicroBooNE (currently operational at 470m along the beam); the new Short-Baseline Near Detector (SBND) will be installed at 110m, and the largest existing LAr-TPC, the ICARUST600, will be placed at 600m. In this talk, we present the current status of the SBND and ICARUS detectors and review the physics reach of the full three- detector SBN program.

        Speaker: Diego Garcia-Gamez
      • 212
        Physics Programme for the SBND (Short-Baseline Near Detector)

        SBND (Short-Baseline Near Detector) is a 112-ton liquid argon TPC neutrino detector under construction in the Fermilab Booster Neutrino Beam. Together with MicroBooNE and ICARUS-T600 detectors, SBND will search for short baseline neutrino oscillations in the 1 eV2 mass range. SBND will also perform detailed studies of the physics of neutrino-argon interactions, thanks to a data sample of millions of electron and muon neutrino interactions. Finally, SBND plays a vital role in the on-going R&D effort to develop the LArTPC technology, testing several technologies that can be used in a future kiloton-scale neutrino detectors for a long-baseline experiment. We will the physics program, with a particular focus on the neutrino cross-section measurements and search for BSM physics as well as discuss the detector design, its current status.

        Speaker: Dr Joel Mousseau (University of Michigan)
      • 213
        The MicroBooNE Detector

        MicroBooNE is a large 170-ton liquid-argon time projection chamber (LArTPC) neutrino experiment located on the Booster neutrino beamline at Fermilab. The experiment first started collecting neutrino data in October 2015. The detector serves as a next step in a phased program towards the construction of massive kiloton scale LArTPC detectors for future long-baseline neutrino physics (DUNE) and is
        the first detector in the short-baseline neutrino program at Fermilab. We will present results on the performance of the detector, including measurements of cosmic-ray reconstruction efficiencies, on Michel electron and muon momentum reconstruction, on noise characterisation and filtering, processing of ionisation electron signals, and on the use of advanced analysis techniques for event reconstruction.

        Speaker: David Caratelli (Fermilab)
      • 214
        Latest Results from MicroBooNE

        The MicroBooNE experiment has been taking data in a LArTPC detector at Fermilab since late 2015. This talk will present initial cross-section results from MicroBooNE, alongside our progress on a short-baseline neutrino oscillation analysis in the region of the MiniBooNE low-energy excess. These results will be discussed in the wider context of MicroBooNE's long-term physics goals of neutrino interaction rates, neutrino oscillations, exotic searches and detector research and development.

        Speaker: Dr Pip Hamilton (Syracuse University)
      • 215
        Status and Prospects of the JSNS$^2$ experiment

        The JSNS$^2$ experiment aims to search for the existence of neutrino oscillations with $\Delta {\rm m}^2$ near 1 eV$^2$ at the J-PARC Materials and Life Science Experimental Facility. A 1 MW proton beam (3 GeV) incident on a mercury target produces an intense neutrino beam from muon decay at rest ($\mu^{+} \rightarrow e^{+} + \bar{\nu}_{\mu} + \nu_{e}$). The oscillation to be searched for is $\bar{nu}_{\mu}$ to $\bar{\nu}_{e}$, detected via the inverse beta decay reaction ($\bar{\nu}_{e} + p \rightarrow e^{+} + n$), which is then distinctively tagged by gammas from neutron capture of Gadolinium. The first of two detectors with 17 tons fiducial volume is currently under construction at a distance of 24 m from the mercury target. JSNS$^2$ is expected to provide the ultimate test of the LSND anomaly by replicating nearly identical conditions. The status of the experiment, which is expected to start by the end of this year, will be discussed and its physics potential reviewed.

        Speaker: Carsten Rott (Sungkyunkwan University)
      • 216
        Search for sterile neutrinos with the T2K far detector

        T2K is a long baseline accelerator neutrino experiment in Japan which studies
        neutrino oscillations with a narrow-band muon neutrino beam peaked at 0.6 GeV.
        The large water Cherenkov detector Super-Kamiokande (SK) located 295 km away
        from the proton target acts as a far detector and provides high quality
        samples for oscillation analysis. In the present study the T2K setup is used
        to search for light sterile neutrinos.
        Sterile neutrinos are hypothetical particles that do not interact via
        weak interactions and couple with active neutrinos only through mixing. They
        are present in many extensions of the Standard Model and can have any masses
        from 0 to the GUT scale. Light sterile neutrinos of eV masses could modify the
        standard 3-flavour oscillation pattern and explain anomalies observed in some
        oscillation experiments.
        A sterile neutrino analysis at T2K was developed to constrain
        $\theta_{24}$ and $\theta_{34}$ mixing elements in the 3+1 sterile neutrino
        model. This is the first study of sterile neutrinos at T2K which is based on
        SK data. To enhance the sensitivity to the effects related to the presence of
        sterile neutrinos, a joint analysis is done using both charged-current and the
        newly implemented neutral-current (NC) oscillation samples (NC$\pi^0$ with 2
        rings observed and NC gamma de-excitation) at the far detector. The primary
        sensitivity for this sterile search comes from NC samples where we are looking
        for a deficit due to the oscillations to the sterile neutrino.
        The analysis strategy and the results obtained for the current T2K
        data (2010-2017 data taking) are presented.

        Speaker: Ka Ming Tsui (University of Tokyo)
      • 217
        Search for heavy neutrinos with the near detector ND280 of the T2K experiment

        Heavy Neutral Leptons (HNLs, heavy neutrinos) with masses below the electroweak
        scale are introduced in some extensions of the Standard Model to address
        consistently such effects as neutrino oscillations, light neutrino masses,
        dark matter and baryon asymmetry. In the mass range below 500 MeV/$c^2$ these
        heavy neutrinos can be produced in pion or kaon decays, and further decay
        themselves into charged particles, hence giving a possibility for their
        The T2K long-baseline neutrino oscillation experiment utilises an
        intense neutrino beam, originating mainly from $\pi$ and K parents. Usage of the
        K flux allows the study of a wider mass range of heavy neutrinos. The near
        detector complex ND280, located 280 m from the target and composed of various
        sub-modules operated inside a magnetic field, provides the tracking
        capabilities to identify the products of HNLs` decays.
        A selection aimed to search for heavy neutrino events in the
        gas-filled ND280 TPCs was developed and optimised to significantly reduce the
        background from active neutrino interactions down to few events for the
        current dataset. After applying the selection to the T2K ND280 data $(12.34 \nu + 6.29 \bar{\nu}) \times 10^{20}$ protons-on-target, 2010-2017 statistics), no
        events in the signal region were observed. The results were used to extract
        limits on the mixing parameters between heavy neutrino and electron-, muon-
        and tau- flavoured currents in the mass range of 140 < $M_{HNL}$ < 493
        MeV/$c^2$. The T2K data allow an improvement of the limits provided by the
        previous experiments such as the CERN PS191 which, together with the BNL E949
        data, put the most stringent constraints in the mass region studied by T2K.

        Speaker: Mathieu Lamoureux (Université Paris-Saclay (FR))
      • 218
        Searches for heavy neutral lepton production and lepton flavour violation in kaon decays at the NA62 experiment

        Searches for heavy neutral lepton (HNL) production in charged kaon
        decays using the data collected by the NA62 experiment at CERN are
        reported. Upper limits are established on the elements of the extended
        neutrino mixing matrix for heavy neutral lepton mass in the range
        130-450 MeV, improving on the results from previous HNL production
        searches. The status and prospects of searches for lepton flavour and
        lepton number violation in kaon decays at the NA62 experiment is also

        Speaker: Michal Zamkovsky (Charles University (CZ))
    • Strong Interactions and Hadron Physics: 4 101 (COEX, Seoul)


      COEX, Seoul

      Convener: Leo Piilonen (Virginia Tech)
      • 219
        Studies of open charm production and properties at LHCb

        LHCb continues to expand its world-leading sample of charmed hadrons collected during LHC’s Run 1 and Run 2. Recent results on charm production and charm hadron lifetimes are presented.

        Speaker: Daniel O'Hanlon (INFN Bologna)
      • 220
        Recent LHCb Results in Charm Spectroscopy

        LHCb continues to expand its world-leading sample of charmed hadrons collected during LHC’s Run 1 and Run 2. With this data set, LHCb is discovering many previously unobserved charmed states and making the most precise determinations of the properties of these states. LHCb’s latest work on the spectroscopy of charmed hadrons is presented.

        Speaker: Jibo He (University of Chinese Academy of Sciences (CN))
      • 221
        Measurement of D ∗ Production in Diffractive Deep Inelastic Scattering at HERA

        Measurements of $D^{∗}(2010)$ meson production in diffractive deep inelastic scattering ($5 < Q^2 < 100$ GeV$^2$) are presented which are based on HERA data recorded at a centre-of-mass energy $\sqrt{s} = 319$ GeV with an integrated luminosity of $287$ pb$^−1$. The reaction $ep\to eXY$ is studied, where the system $X$, containing at least one $D^{∗}(2010)$ meson, is separated from a leading low-mass proton dissociative system $Y$ by a large rapidity gap. The kinematics of $D^{∗}$ candidates are reconstructed in the $D^{∗}\to K\pi\pi$ decay channel. The measured cross sections compare favourably with next-to-leading order QCD predictions, where charm quarks are produced via boson-gluon fusion. The charm quarks are then independently fragmented to the $D^{∗}$ mesons. The calculations rely on the collinear factorisation theorem and are based on diffractive parton densities previously obtained by H1 from fits to inclusive diffractive cross sections. The data are further used to determine the diffractive to inclusive $D^{∗}$ production ratio in deep inelastic scattering.

        Eur.Phys.J.C77 (2017), 340 [arxiv:1703.09476]

        Speaker: Andrew Mehta (University of Liverpool (GB))
      • 222
        Open heavy-flavour measurements in proton-proton collisions with ALICE at the LHC.

        In proton-proton (pp) collisions, open heavy-flavour hadrons are valuable tools for testing perturbative Quantum Chromo-Dynamics (pQCD) calculations. Indeed, the large heavy-quark masses (with respect to the QCD scale parameter) allow to calculate the heavy-quark production cross section, as perturbation series in $\alpha_S$ down to $p_{\mathrm T}=0$.

        The ALICE experiment has measured D mesons in pp collisions, via the reconstruction of hadronic decay channels at central rapidity, as well as muons (electrons) from semi-leptonic decay of heavy-flavour hadrons at forward (mid) rapidity. These measurements, performed over a wide range of transverse momentum, in several rapidity regions and for different collision energies, have much smaller uncertainties than the typical theoretical ones. Thus, ALICE results challenge state-of-the-art pQCD calculations such as FONLL and GM-VFNS and, besides, add sensitivity to gluon PDF.

        More differential measurements help studying further charm production: the analysis of D-meson-tagged jets allows measuring charm jet production, and addressing charm-quark production processes and charm fragmentation properties. Additionally, multiplicity-dependent measurements of heavy-flavour production provide insight into multi-parton interactions and the possible interplay of soft and hard processes.

        In this talk, new and most recent ALICE results on open heavy-flavours in pp collisions at $\sqrt{s}=2.76$, 5, 7, 8 and 13 TeV will be presented and compared with theoretical and model predictions.

        Speakers: Julien Charles Hamon (Institut Pluridisciplinaire Hubert Curien (FR)) , Andrea Rossi (Universita e INFN, Padova (IT))
      • 223
        Precise measurement of the $D^{*}(2010)^+ - D^+$ mass difference

        We measure the mass difference, $\Delta m_+$, between the $D^{*}(2010)^+$ and the $D^+$, using the decay chain $D^{*}(2010)^+\to D^+ \pi^0 $ with $ D^+ \to K^- \pi^+ \pi^+$. The data were recorded with the BABAR detector at center-of-mass energies at and near the $\Upsilon(4S)$ resonance, and correspond to an integrated luminosity of approximately $468 \, \mbox{fb}^{-1}$. We measure   $\Delta m_+ = \left(140\,601.0 \pm 6.8\,[{\rm stat}] \pm 12.9 \,[{\rm syst}]\right) \, \mbox{keV} $. 
        We combine this result with a previous BaBar measurement of $\Delta m_0\equiv m(D^{*}(2010)^+) - m (D^0)$ to obtain  $\Delta m_D =  m(D^+) - m(D^0) = \left(4\,824.9 \pm 6.8\,[{\rm stat}] \pm12.9\,[{\rm syst}]\right) \, \mbox{keV}$.
        These results are compatible with, and approximately five times more precise than, previous world averages.

        Speaker: Dr Liang Sun (Wuhan University (CN))
      • 224
        ATLAS results on quarkonia and its associated 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 differential measurements from ATLAS of (associated-) quarkonium production

        Speakers: Cesare Bini (Universita di Roma I "La Sapienza") , Cesare Bini (Sapienza Universita e INFN, Roma I (IT))
      • 225
        Measurements of heavy flavor production at CMS

        Recent results on the production of beauty and charm at the CMS detector, based on data collected at Run 1 and Run 2 of LHC are presented. Measurements of single and double quarkonium production, Lambda_b polarization, open charm and B hadrons cross sections and ratios are reported.

        Speaker: Nuno Leonardo (LIP)
    • Top Quark and Electroweak Physics: 3 209 (COEX, Seoul)


      COEX, Seoul

      Convener: Liang Han (University of Science and Technology of China (CN))
      • 226
        A Precision Event Generator for EW Radiative Corrections in Hadron Scattering: KKMC-hh

        KKMC-hh is a precision event-generator for Z production and decay in hadronic collisions, which
        applies amplitude-level resummation to both initial and final state photon radiation, including
        perturbative residuals exact through order $\alpha^2L$, together with exact order $\alpha$ electroweak matrix element corrections. We present some comparisons to other programs and results showing the effect of multi-photon radiation for cuts motivated by a recent ATLAS W -mass analysis. We also show preliminary untuned comparisons of the electroweak corrections of KKMC-hh to those of HORACE, which includes order exact $\alpha$ EW corrections with resummed final-state photon radiation.

        Speakers: Prof. Bennie Ward (Baylor University) , Bennie Ward (Baylor University (US))
      • 227
        Determination of electroweak parameters using H1 inclusive DIS data

        An improved determination of electroweak (EW) parameters using H1 inclusive neutral current and charged current DIS cross sections is presented. The analysis benefits from the usage of the previously published cross sections using longitudinally polarised lepton beams. The parameters are determined in a combined fit of EW parameters together with PDFs. The predictions include NNLO QCD corrections for the PDF and structure function calculations, and the corrections at the leptonic vertex are obtained in the on-shell scheme including the full set of 1-loop corrections. The analysis determines the weak neutral-current couplings of the light quarks and thus tests potential contributions beyond the SM. The mass of the W-boson is determined and a precision of 115 MeV is achieved.

        Speaker: Zhiqing Philippe Zhang (LAL, Orsay (FR))
      • 228
        Results of vector boson scattering from CMS

        The production of massive vector boson pairs is a key process for the understanding of the non-abelian gauge structure of the standard model and for the comprehension of the electroweak symmetry breaking mechanism. The study of the production of vector boson pairs with the presence of two jets in the event allows to measure the electroweak production of vector bosons in association with jets, in particular made up through vector boson scattering (VBS) processes. In this presentation, we will report the recent results of the production of diboson in association with two jets. The constraints on anomalous quartic couplings will be presented as well.

        Speaker: Kenneth Long (University of Wisconsin Madison (US))
      • 229
        Tests of the electroweak sector sector with Diboson final states at the ATLAS Experiment

        Measurements of the cross sections of the production of pairs of electroweak gauge bosons at the LHC constitute stringent tests of the electroweak sector and provide model-independent means to search for new physics at the TeV scale. Similarly, the electroweak production of vector bosons in proton-proton collisions tests the gauge structure of the Standard Model. The ATLAS collaboration has performed detailed measurements of integrated and differential cross sections of the production of ZZ di-boson pairs as well as WZ and WW di-boson pairs at 8 and 13 TeV. The results will be presented and compared to predictions at NLO (and NNLO) in pQCD. Constraints on new physics are provided by setting limits on anomalous triple gauge couplings. If available, a measurement of the unfolded 4-lepton mass at 13 TeV will be presented.

        Speaker: Rustem Ospanov (University of Science and Technology of China)
      • 230
        New Results on Multi-Boson Production with the ATLAS Detector

        Measurements of the cross sections of the production of three electroweak gauge bosons and of vector-boson scattering processes at the LHC constitute stringent tests of the electroweak sector of the Standard Model and provide a model-independent means to search for new physics at the TeV scale. The ATLAS collaboration searched for the production of three W bosons or of a W boson and a photon together with a Z or W boson at a center of mass energy of 8 TeV. ATLAS also searches for the electroweak production of diboson final states, where evidence was found for the exclusive production of W boson pairs. If available also further results on the electroweak production of diboson pairs will be presented. All results have been used to constrain anomalous gauge couplings and have been compared to the latest theory predictions.

        Speakers: Marc-Andre Pleier (Brookhaven National Laboratory (US)) , Marc-Andre Pleier (Brookhaven National Laboratory (US))
      • 231
        Multiboson production at CMS

        Precision measurements of multi-boson production is a validation of the Standard Model. These multi-boson processes are a background to Higgs measurements and searches for Beyond the Standard Model physics. In this talk, we present the recent measurements of multiboson final states performed in CMS, involving W, Z and photon combinations. Inclusive and differential cross sections are compared to different theoretical predictions. Phase space regions that provide sensitivity to anomalous triple or quartic gauge couplings are also investigated. These coupling strengths are directly related to the broken electroweak symmetry and deviations from the SM are a clear signal of new physics.

        Speaker: Riccardo Bellan (Universita e INFN Torino (IT))
      • 232
        The role of positron polarization for the inital 250 GeV stage of the International Linear Collider

        The International Linear Collider is now proposed with a staged machine design, with the first stage at sqrt(s)=250 GeV and an integrated luminosity goal of 2 ab^-1. One of the questions for the machine design is the importance of positron polarization. In this report, we review the impact of positron polarization on the physics goals of the 250 GeV stage of the ILC and demonstrate that positron polarization has distinct advantages.

        Speaker: Jürgen Reuter (DESY Hamburg, Germany)
    • Accelerators: Physics, Performance, and R&D for Future Facilities: Accelerator Physics/Technology 105 (COEX, Seoul)


      COEX, Seoul

      Convener: Manqi Ruan (Chinese Academy of Sciences (CN))
      • 233
        Superconducting RF Cavities R&D Towards Future High Energy Accelerators

        Modern accelerators for High Energy Physics (ILC, FCC-ee, FCC-he, CEPC) demand efficient operation of SRF cavities. Since low cryogenic losses and high quench fields are essential to save in both capital and operational cost, basic SRF R&D on niobium cavities is focused on increasing the quality factor at the highest accelerating gradient.
        The talk will be focused on the description of the strategies adopted to increase quality factor and accelerating gradient in SRF cavities. Innovative surface preparations can allow for future SRF-based accelerators that wouldn’t otherwise be feasible, by cutting the capital cost of their realization.
        Layered SRF surfaces and smart engineering of the impurities profile at the RF surface are promising technologies that may substantially decrease the cost of accelerators and possibly allow for higher duty cycle operation. The physics behind these new technologies will be described and the impact their application would bring in the accelerator world will be analyzed in detail.
        Part of the talk will also address the description of new directions being explored in the SRF community to further increase accelerating gradients beyond the current limitations and on the cost savings they might allow.

        Speaker: Mattia Checchin (FNAL - IIT)
      • 234
        SQUID-based BPM for proton EDM experiment

        The pEDM experiment aims to search for the electric dipole moment (EDM) of proton with $10^{-29}$ e-cm sensitivity, approximately 5 orders of magnitude better than the current experimental limit. The experiment is designed to store counter-rotating proton beams in an all-electric storage ring. The EDM of the particles will couple with the radial electric field, causing a spin growth around the radial axis in the particle's rest frame. The growth rate of this precession will be proportional to the EDM of the proton.

        Magnetic field is a major source of systematic errors as it couples with magnetic dipole moment and dominates the spin precession. Among possible combinations, average radial magnetic field (B_r) is the most critical one. It should be kept at 10aT level. We are developing a novel BPM that is based on SQUID magnetometers for measuring the average magnetic field.

        Speaker: Selcuk Haciomeroglu (Institute for Basic Science)
      • 235
        LUCID: The ATLAS Luminosity Detector

        The LUCID detector is the main luminosity provider of the ATLAS experiment and the only one able to provide a reliable luminosity determination in all beam configurations, luminosity ranges and at bunch-crossing level.
        LUCID was entirely redesigned in preparation for Run 2: both the detector and the electronics were upgraded in order to cope with the challenging conditions expected at the LHC center of mass energy of 13 TeV and with 25 ns bunch-spacing.
        An innovative calibration system based on radioactive 207 Bi sources deposited on the quartz window of the readout photomultipliers was implemented, resulting in the ability to control the detectors long time stability at few percent level.
        A description of the detector and its readout electronics will be given as well as preliminary results on the ATLAS luminosity measurement and related systematic uncertainties.

        Speaker: Dr Federico Lasagni Manghi (Universita e INFN, Bologna (IT))
      • 236
        Van der Meer calibration of the CMS luminosity detectors in 2017

        To guarantee smooth and uninterrupted luminosity measurements the CMS experiment is equipped in Run II with three online luminometers: the Pixel Luminosity Telescope (PLT), the Fast Beam Condition Monitor (BCM1F) and the Forward Calorimeter (HF). For the offline luminosity measurement and a cross check of the online detectors the pixel detector is used (Pixel Cluster Counting, PCC). For the calibration of the luminometers once per year a full program of van der Meer (VdM) scans is performed. It consists of series of standard VdM scans and 4 imaging scans. In the standard VdM scans both beams are moving across each other and the transverse size of the beam overlap is defined. Imaging VdM scans are required to disentangle XY correlation. For steering magnet calibrations, under the special beam conditions during the VdM scan, the length scale (LS) calibration is performed. Detailed studies of the systematic effects of beam-beam deflections, orbit drift, LS calibration and unbunched beam correction allow precise luminosity calibration. The methodology of the luminosity calibration and final uncertainty on the integrated luminosity will be presented.

        Speakers: Dr Moritz Guthoff (Deutsches Elektronen-Synchrotron (DE)) , Olena Karacheban (CERN) , Paul Lujan (Universita e INFN, Padova (IT)) , Chris Palmer (Princeton University (US))
    • Beyond the Standard Model: 5 203 (COEX, Seoul)


      COEX, Seoul

      Convener: Archil Kobakhidze (The University of Sydney)
      • 237
        Flavour Anomalies in Rare Decays at LHCb

        Rare decays are powerful probes for Physics beyond the Standard Model (SM), as new particles can have a large impact on physics observables. Recent results on lepton universality tests and measurements of branching fractions and angular distributions of rare b->sll decays have shown tensions with the SM predictions. The LHCb experiment is ideally suited for the study of the these flavour anomalies, due to its large acceptance, precise vertexing and powerful particle identification capabilities. The latest results from LHCb on the flavour anomalies will be presented and their interpretation will be discussed.

        Speaker: Lorenzo Capriotti (University of Manchester (GB))
      • 238
        Search for vector-like quarks with the ATLAS Detector

        Vector like quarks appear in many theories beyond the Standard Model as a way to cancel the mass divergence for the Higgs boson.  The current status of the ATLAS searches for the production of vector like quarks will be reviewed for proton-proton collisions at 13 TeV.  This presentation will address the analysis techniques, in particular the selection criteria, the background modeling and the related experimental uncertainties.  The results and the complementarity of the various searches will be discussed.

        Speaker: Allison Mccarn Deiana (University of Michigan (US))
      • 239
        Searches for vector-like quarks at CMS

        We present results of searches for massive vector-like top and bottom quark partners using proton-proton collision data collected with the CMS detector at the CERN LHC at a center-of-mass energy of 13 TeV. Single and pair production of vector-like quarks are studied, with decays into a variety of final states, containing top and bottom quarks, electroweak gauge and Higgs bosons. We search using several categories of reconstructed objects, from multi-leptonic to fully hadronic final states. We set exclusion limits on both the vector-like quark mass and cross sections, for combinations of the vector-like quark branching ratios.

        Speaker: Justin Pilot (University of California Davis (US))
      • 240
        Searches for Long Lived Particles at LHCb

        A flexible trigger system, excellent vertex locator, particle identification detectors, and forward acceptance allow unique searches for long-lived particles to be performed at LHC energies using data collected with the LHCb detector. A summary of results will be presented, including searches for long-lived particles decaying into lepton or jets or coming from B meson decays.

        Speaker: Carlos Vazquez Sierra (Nikhef National institute for subatomic physics (NL))
      • 241
        Complementarity of ATLAS Searches for s-channel Resonance Production in Bosonic an Leptonic Final States

        Many theories beyond the Standard Model predict new s-channel resonances decaying into two bosons (WW,ZZ,WZ,WH,ZH) and possibly leptons (ll, lv), such as a new heavy scalar singlet, a new heavy vector-boson triplet, or a heavy spin-2 graviton in the bulk Randall-Sundrum model. This talk will summarize relevant ATLAS searches at the LHC using proton-proton collision data collected at a centre-of-mass energy of 13 TeV and show their complementarity.

        Speaker: Stephane Yves G Willocq (University of Massachusetts (US))
      • 242
        Searches for heavy resonances decaying into Z, W and Higgs bosons at CMS

        A summary of searches for heavy resonances with masses exceeding 1 TeV decaying into dibosons is presented, performed on data produced by LHC pp collisions at $\sqrt{s}$ = 13 TeV and collected with the CMS detector during 2016 and 2017. The common feature of these analyses is the boosted topology, namely the decay products of the considered bosons (both electroweak W, Z bosons and the Higgs boson) are expected to be highly energetic and close in angle, leading to a non-trivial identification of the quarks and leptons in the final state. The exploitation of jet substructure techniques allows to increase the sensitivity of the searches where at least one boson decays hadronically. Various background estimation techniques are adopted, based on data-MC hybrid approaches or relying only in control regions in data. Results are interpreted in the context of the Warped Extra Dimension and Heavy Vector Triplet theoretical models, two possible scenarios beyond the standard model.

        Speaker: Simon Regnard (University of California Los Angeles (US))
    • Computing and Data Handling: Detector Simulation Tools 104 (COEX, Seoul)


      COEX, Seoul

      Convener: Elizabeth Sexton-Kennedy (Fermi National Accelerator Lab. (US))
      • 243
        Geant4 Detector Simulations for Future HEP Experiments

        The experimental programs planned for the next decade are driving developments in the simulation domain; they include the High Luminosity LHC project (HL-LHC), neutrino experiments, and studies towards future facilities such as Linear Colliders (ILC/CLIC) and Future Circular Colliders (FCC). The next-generation detectors being planned for long-term future programs will have increased granularity. Detector simulation plays a crucial role in their design and conception. In order to achieve the desired precision in physics measurements, whilst avoiding that the simulation dominates the systematic uncertainties, more accurate simulations and larger Monte Carlo samples will be needed. This presents major challenges both for the development of more accurate models of physics interactions and for the performance of the software used to implement them. In this paper, we will discuss the status of the most widely used detector simulation toolkit, Geant4, in the context of detector R&D for present and future facilities. We highlight, in particular, the need to review some of the physics models’ assumptions, approximations and limitations in order to increase precision, and to extend the validity of models up to FCC-hh energies (100 TeV). Results will be shown of recent major improvements in the multiple scattering model of electrons and positrons and a more accurate theoretical description of the Landau-Pomeranchuk-Migdal effect, which plays a significant role at high energies. We will outline the ambitious plans that are foreseen for the further theoretical review of major processes that are a high priority for future HEP experiments.

        Speaker: Dr Farah Hariri (CERN)
      • 244
        First assessment of new Evaluated Data Libraries for Monte Carlo particle transport

        Evaluated data libraries are the foundation of physics modeling in Monte Carlo particle transport codes, such as Geant4, FLUKA and MCNP, which are used in high energy and nuclear physics experiments, accelerator studies and detector development. They encompass recommended cross sections, nuclear and atomic parameters, which may derive from theoretical calculations, evaluations of experimental data or a combination of both. New versions of major, widely used evaluated data libraries were released in early 2018 by the IAEA (International Atomic Energy Agency) and the NNDC (National Nuclear Data Center, BNL); among them, the new data libraries for electron-photon transport represent substantial evolutions with respect to those currently in use, which date back to more than 20 years ago. The changes concern both the physics content and the data structure, which in turn affect the reliability and the computational performance of simulations. We review the main features of the new data libraries with emphasis on what has changed, and present a first assessment of their physics quality and of their effects on computational performance in the Geant4 environment. These results provide quantitative and objective elements for developers and users of Monte Carlo codes to evaluate the impact of migrating simulations to new data libraries on sound grounds. The assessment also highlights opportunities for improvement in future releases.

        Speaker: Maria Grazia Pia (INFN e Universita Genova (IT))
      • 245
        Simulating fix-target and heavy-ion collisions in LHCb

        The LHCb experiment is a fully instrumented forward spectrometer designed for precision studies in the flavour sector of the standard model with proton-proton collisions at the LHC. As part of its expanding physics programme, LHCb collected data also during the LHC proton-nucleus collisions in 2013 and 2016 and during nucleus-nucleus collisions in 2015. These datasets provide access to unique kinematic coverage due to the forward pseudo-rapidity of LHCb. Furthermore, in 2015 LHCb commissioned the internal gas target SMOG, becoming the only LHC experiment with a programme of fixed target physics. Any of these particular collision conditions required a different operational setup, as well as dedicated simulation production based on heavy-ion Monte-Carlo event generators and interface extensions of the standard LHCb simulation framework. In this talk, we present the work done to implement such a variety of simulation productions for heavy-ion collisions, and to validate the produced samples. The future perspectives of the heavy-ion collision simulations at LHCb will also be discussed.

        Speaker: Dr Benjamin Audurier (Universita e INFN, Cagliari (IT))
      • 246
        A palette of fast simulations in LHCb

        LHCb is one of the major experiments operating at the Large Hadron Collider at CERN. The richness of the physics program and the increasing precision of the measurements in LHCb lead to the need of ever larger simulated samples. This need will increase further when the upgraded LHCb detector will start collecting data in the LHC Run 3. Given the computing resources pledged for the production of Monte Carlo simulated events in the next years, the use of fast simulation techniques will be mandatory to cope with the expected dataset size. A number of fast simulation options are already available or under development to complement the full simulation of the LHCb detector based on Geant4. They include simulating a subset of the generated particles, simplifying the detector geometry, re-using the underlying event, replacing the detailed simulation of the calorimeter with a faster version based on hit libraries, or using a fully parametric simulation of the detector. We present the available options, describe their applications and discuss the future developments. We also mention how we intend to make the different options transparently available in the LHCb simulation framework.

        Speaker: Mark Peter Whitehead (Rheinisch Westfaelische Tech. Hoch. (DE))
    • Detector: R&D for Present and Future Facilities: 5 103 (COEX, Seoul)


      COEX, Seoul

      Convener: Alexander Oh (University of Manchester (GB))
      • 247
        The upgraded trigger system and di-τ trigger strategies of the ATLAS detector at the HL-LHC

        When LHC enters the High Luminosity (HL-LHC) phase, the instantaneous luminosity will increase from the current 2 x 10^34 cm-2 s-1 (Run II) to a maximum expected value of 7.5 x 10^34 cm-2 s-1, equivalent to 200 interactions per bunch crossing, and the estimated integrated luminosity will reach 3000 fb-1.
        New strategies are needed in order to make triggers more selective and to keep pT thresholds for leptons close to the current ones.
        The current trigger system is based on a Level-1 hardware trigger plus a High Level Trigger (HLT) implemented in software, two scenarios are being considered for the HL-LHC phase.
        The first one is a single Level-0 which will do a preliminary selection of data to reduce the rate to 1 MHz with a latency of 6 μs followed by a High Level Trigger. This corresponds to a 200 kHz target for a di-τ trigger.
        The second scenario would reduce the event rate to 2-4 MHz at Level-0, then a Level-1 trigger will further reduce it to 600-800 kHz, followed again by a High Level Trigger.
        The new trigger system will rely on better spatial resolution of the LAr calorimeter of ATLAS, whose granularity will be 4 times improved at Level-0 and 16 times at Level-1. This will improve the turn-on curves and the matching between tracks and clusters, it will make transverse energy measurements of reconstructed objects more accurate and it will allow the use of more sophisticated jet algorithms.
        Physics motivations for the trigger upgrade at HL-LHC together with an overview of the new trigger system will be given.
        The current status of the di-τ trigger at the future HL-LHC Level-0 will then be shown. This study has been performed through simulations of the hadronic decay of the Higgs boson into two taus at a center of mass energy of 14 TeV under a pile-up conditions corresponding to 200 interactions per bunch crossing.
        In particular, results on the performance (in terms of turn-on curves and rejection power of the algorithm) will be shown along with the challenges related to the development of this trigger in such a very high pile-up environment.

        Speaker: Stephanie Majewski (University of Oregon (US))
      • 248
        Performance of missing transverse momentum reconstruction at the CMS detector in 13 TeV data

        The precise measurement of the missing transverse momentum (MET) observable is critical for standard model measurements involving W, Z, and the Higgs bosons, and top quarks. In addition, MET is one of the most important kinematic observable used in searches for physics beyond the standard model targeting new weakly interacting neutral particles. A detailed understanding of various effects due to the high collision rate at the CMS detector during the 13 TeV data-taking period of the LHC both in data and simulation is important to achieve the most optimal MET performance. In this talk, we will present the studies of MET reconstruction algorithms using the CMS detector at the LHC.

        Speaker: Leonora Vesterbacka (ETH Zurich (CH))
      • 249
        The CLIC detector

        The proposed Compact Linear Collider (CLIC) will provide electron-positron collisions at centre-of-mass energies from a few hundred GeV up to 3 TeV. CLIC offers a rich precision physics program, and a high sensitivity to a wide range of possible new phenomena. The precision required for such measurements and the specific conditions imposed by the CLIC beam structure put strict requirements on the detector design and technology developments. This includes ultra-low mass vertexing and tracking systems with small cells, highly granular imaging calorimeters, and a precise hit-timing resolution for all subsystems. Ambitious R&D programs for silicon tracking detectors and calorimeters are pursued, addressing the challenging detector requirements with innovative new technologies. A variety of detector optimisation studies have been carried out to establish the overall detector performance and to assess the impact of different technology options. The resulting optimised detector model has been integrated in the CLIC full-detector simulation framework. This contribution reviews the optimisation studies performed for critical parameters of the CLIC detector, presents the detector performance achieved in full-detector simulations, and gives an overview of the ongoing hardware R&D.

        Speaker: Eva Sicking (CERN)
      • 250
        Design and performance studies of the calorimeter system for a FCC-hh experiment

        The physics reach and feasibility of the Future Circular Collider (FCC) with centre of mass energies up to 100 TeV and unprecedented luminosity is entering its final phase before releasing a Conceptual Design Report. The new energy regime opens the opportunity for the discovery of physics beyond the standard model. 100 TeV proton-proton collisions will produce very high energetic particle showers in the calorimeters from both light jets and boosted bosons/top. The reconstruction of such objects sets the calorimeter performance requirements in terms of shower containment, energy resolution and granularity. Furthermore, high-precision measurements of photons and electrons over a wide energy range are crucial to fully exploit the FCC-hh physics potential, especially given the large amount of collisions per bunch crossing the detectors will have to face (pile-up of $\left<\mu\right>=1000$).
        We will present the current reference technologies for the calorimeter system of the FCC-hh detector: Liquid Argon (LAr) as the active material in the electromagnetic calorimeters, and the hadronic calorimeters for $|\eta|>1.3$ (Endcap and Forward region), and a Scintillator-Steel (Tile) calorimeter as hadronic calorimeter in the Barrel region. The talk will focus on the performance studies for single particles and jets in the combined calorimeter system. We will introduce the simulation framework and the reconstruction chain, that includes the calibration and clustering of calorimeter cells and the estimation of pile-up induced, and electronics noise. In conclusion, the achieved performances will be compared to the physics benchmarks of the FCC-hh experiment.

        Speaker: Coralie Neubuser (CERN)
      • 251
        Moliere radius measurement using a compact prototype of LumiCal in a test set-up

        The FCAL collaboration has performed a design study for luminometers at future electron-positron colliders. Compact sampling calorimeters with precisely positioned silicon sensors and a fast readout will reach the necessary performance even in the presence of background from beamstrahlung and two-photon processes. A prototype calorimeter has been built with special focus on ultra-thin fully instrumented sensor planes to ensure a very small Moliere radius. Results of a measurement in a 5 GeV electron beam on the performance will be presented.

        Speaker: Veta Ghenescu
      • 252
        Status Report on Inner Tracking System Upgrade of ALICE

        The ALICE Collaboration is preparing a major upgrade of the ALICE detector, planned for installation during the second long LHC shutdown. The construction is expected to be completed by 2020 for data taking until 2029. A key element of the ALICE upgrade is the construction of a new, ultra-light, high-resolution Inner Tracking System (ITS).
        With respect to the current ITS, this upgrade is aiming at a better position resolution (5 micron), a lower material budget (0.3% X0 for the three innermost layers) and a faster readout (up to 100 kHz in Pb-Pb collisions). This will be obtained by seven concentric detector layers based on an advanced Monolithic Active Pixel Sensor (MAPS) chip, with a pixel pitch of 30x30um^2.
        I will present the general layout and main components of the new ITS, a summary of the R&D activities, the current status and outlook.

        Speaker: In Kwon Yoo (Pusan National University (KR))
      • 253
        Upgrade of ALICE forward detectors

        In 2019-2020 the upgrade of CERN LHC will increase the luminosity and the collision rate beyond the design parameters of several of the key ALICE detectors [1]. To benefit from the improved performance of the LHC, ALICE will install two new forward detectors: the Fast Interaction Trigger (FIT) [2][3] and the Muon Forward Tracker (MFT) [4]. A further upgrade opportunity might arise during the shutdown between Run 3 and Run 4 when the Forward Calorimeter (FoCal) may be added to the ALICE setup.

        The presentation will contain a short description of the new forward detectors. The required functionality and the main physics goals will be given together with the main highlights concerning the design and performance of the detector prototypes.

        The main focus will be on FIT. It will replace existing trigger and multiplicity detectors: T0, V0 and FMD. FIT will consist of two Cherenkov detector arrays and a large sectored scintillator ring on opposite sides of the interaction point (IP). FIT will be capable of operating at the sustained Pb-Pb interaction rate of 50 kHz in a continuous readout mode. It will provide the collision time with resolution better than 40 ps and trigger with maximum latency of 400 ns. Several online triggering modes will be available, including multiplicity (centrality) trigger and vertex position trigger. FIT will be able to reconstruct the collision centrality and reaction plane with resolution similar to that of the present ALICE apparatus, while the trigger efficiency for pp collisions will be improved.

        The main role of MFT is to add secondary vertex reconstruction capabilities for muon tracks at forward rapidity and to supplement the acceptance of the already operating Muon Spectrometer. The MFT will consist of a stack of 5 disks mounted in front of the hadron absorber shielding the Muon Spectrometer from the IP. The active part is made of custom-designed Monolithic Active Pixel Sensors (MAPS). Most prominent properties of MFT include radiation hardness, low material budget, high granularity of pixels and readout speed.

        A SiW electromagnetic calorimeter, FoCal, is considered as a possible upgrade to the ALICE detector. It should be characterized by a very high granularity allowing for $\gamma/\pi_0$ discrimination, especially for very high momenta. The main candidates to instrument the sensitive area are CMOS pixel sensors.

        Speaker: Maciej Slupecki (University of Jyvaskyla (FI))
    • Education and Outreach: 1 209 (COEX, Seoul)


      COEX, Seoul

      Convener: Kang Young Lee (GNU, Korea)
      • 254
        Public analysis of Belle II Data

        A small Belle II data sample will be available to the general public through an interactive graphical application which includes basic particle selection tools for reconstructed particles. The application is using an open source library Blockly running in an HTML5 capable browser. In the application, different particle decays can be described by selecting and combining particles from the data file. The application includes easy histogramming and cutting tools and enables display of the ROOT histograms. After submission, a pseudocode is generated by the user interface. The code is interpreted by the server which then runs back-end analysis and sends back the resolution histograms to the client. The browser app also enables for the interactive fitting of the histograms, thus enabling even more complex analyses. The application can be run on a single public web server aimed at a single access or in a virtual appliance for use in a classroom consisting. The virtual appliance consists of a Linux OS, data sample, an analysis framework and a private web server. In the presentation, I will describe the application, demonstrate its use and outline our plans for future development.

        Speaker: Leo Piilonen (Virginia Tech)
      • 255
        Belle2VR – An Interactive Virtual Reality Visualization of Particle Physics

        I describe a novel interactive virtual reality visualization of particle physics, designed as an educational tool for learning about and exploring the electron-positron collision events in the Belle II experiment at the SuperKEKB colliding-beam facility at KEK in Japan. The visualization is designed for untethered, locomotive virtual reality, allowing multiple simultaneous users to walk naturally through a virtual model of the Belle II detector and interact with and gather information about the particles that result from collisions. Belle2VR displays the detailed GEANT4-simulated history of each collision event superimposed on the complete detector geometry; the user can move freely through the scalable detector geometry and manipulate the history timeline with handheld controllers. Developed by an interdisciplinary team of researchers in physics, education, and virtual environments, the simulation will be integrated into the undergraduate physics curriculum at Virginia Tech. I describe the tool, including visualization features and design decisions, and outline our plans for future development.

        Speaker: Leo Piilonen (Virginia Tech)
      • 256
        8 Hours of the NicoNico live webcast from the Belle II experimental hall

        Phase 2 of the Belle II experiment is about to begin. A new super-B factory facility, utilizing the SuperKEKB accelerator and the Belle II detector, is designed to search for as yet unknown "New Physics".

        The outreach teams of KEK and the Belle II collaboration worked together for more than a year to make the Belle II/SuperKEKB project better known in Japan as well as in the world.

        Significant milestones in our roadmap are:
        (1) the start of Phase 1 in Feb. 2016 and first turns in the SuperKEKB accelerator,
        (2) "the Belle II roll-in", integration of the detector and the accelerator in Apr. 2017, and
        (3) Phase2 and first collisions in the coming months,
        the list will go on as the project develops towards its design luminosity.

        In this talk, we will focus on "the Belle II roll-in" .
        We cooperated with the "Niconico" livestreaming service in Japan and live-casted the roll-in event from the Belle II experimental hall for over 8 hours.

        We would like to share know-how on how we collaborated, how we risk-hedged , and how impressive it was, and exchange opinions with other institutions who have tried livecasting important events.

        Speaker: Shota Takahashi (KEK)
      • 257
        ATLAS Open Data project

        Exploring the many ways that public High Energy Physics resources are employed to teach and outreach particle physics and computer science.

        The current ATLAS model of Open Access to recorded and simulated data offers the opportunity to access datasets with a focus on education, training and outreach. This mandate supports the creation of platforms, projects, software, and educational products used all over the planet. We describe the overall status of ATLAS Open Data (http://opendata.atlas.cern) activities, from core ATLAS activities and releases to individual and group efforts, as well as educational programs, and final web or software-based (and hard-copy) products that have been produced or are under development. The relatively large number and heterogeneous use cases currently documented is driving an upcoming release of more data and resources for the ATLAS Community and anyone interested to explore the world of experimental particle physics and the computer sciences through data analysis.

        Speaker: Meirin Oan Evans (University of Manchester (GB))
      • 258
        The "social content" strategy of the ATLAS Experiment

        Social media is an essential tool for communicating particle physics results to a wide audience. This presentation will explore how the nature of social media platforms has impacted the content being shared across them, and the subsequent effect this has had on the user experience. The ATLAS Experiment has adapted its communication strategy to match this social media evolution, producing content specifically targeting this emerging audience. The success of this approach is examined and the effect on user experience is evaluated.

        Speaker: Katarina Anthony (Universita degli Studi di Udine (IT))
      • 259
        Status of outreach activities at LHCb

        Status of outreach activities at the LHCb experiment at LHC is presented. LHCb is visible on the web with the public page news, Instagram, Facebook and online event display. Masterclasses activities for school boys and girls cover the whole planet. The surface exhibition above the LHCb proton-proton collision point is being constantly developed. Cameras in the control room allow Virtual Visits of the LHCb experiment. Laser scan of LHCb detector is performed to archive its 3D images as an important heritage for humanity. These images will also be used to develop 3D Virtual Reality files for visitors and schools. New film covering a major LHCb discovery is finalized.

        Speaker: Dr Luca Pescatore
    • Formal Theory Development 205 (COEX, Seoul)


      COEX, Seoul

      Convener: Sangmin Lee (Unknown)
      • 260
        On Geometric classification of 5d SCFTs

        We formulate geometric conditions necessary for engineering 5d superconformal field theories (SCFTs) via M-theory compactification on a local Calabi-Yau 3-fold. Extending the classification of the rank 1 cases, which are realized geometrically as shrinking del Pezzo surfaces embedded in a 3-fold, we propose an exhaustive classification of local 3-folds engineering rank 2 SCFTs in 5d. This systematic classification confirms that all rank 2 SCFTs predicted using gauge theoretic arguments can be realized as consistent theories, with the exception of one family which is shown to be non-perturbatively inconsistent and thereby ruled out by geometric considerations. We find that all rank 2 SCFTs descend from 6d (1,0) SCFTs compactified on a circle possibly twisted with an automorphism together with holonomies for global symmetries around the Kaluza-Klein circle.

        Speaker: Prof. Heechoel Kim (Postech)
      • 261
        Analyticity Properties of Scattering Amplitude in Higher Dimensional Field Theories

        I consider analyticity properties of scattering amplitude in higher dimensional field theories in the frame works of LSZ Axiomatic field theory. I prove existence of the Lehmann-Martin ellipse and prove generalized Jost-Lehmann-Dyson theorem
        to achieve this goal. Here the basis for partial wave expansion is Gegenbaur
        polynomial. I also prove analog of the Froissart-Martin bound for such theories.
        J. Maharana, J. Math. Phys. (1917)

        Speaker: Prof. Jnanadeva Maharana (Institute of Physics, Bhubaneswar)
      • 262
        SSB in tensor theories and matrices

        Counting observables in tensor and in matrix theories reveals a non-trivial relation between them. By means of a SSB mechanism, we explore the connection between tensor theories with symmetry group U(N)^d and symmetrized tensor theories which transform under U(N). We see that, in such a case, the Goldstone boson space precisely organizes itself into a collection of d-1 matrices transforming in the adjoint.

        Speaker: Dr Pablo Diaz Benito (IBS)
    • Higgs Physics: 5 201 (COEX, Seoul)


      COEX, Seoul

      Conveners: Jae Sik Lee (Chonnam National University) , Samira Hassani (Université Paris-Saclay (FR))
      • 263
        The latest results of the measurement of the Higgs boson decaying into two photons at CMS

        The latest results of the measurement of the Higgs boson decaying into two photons will be presented. The analysis is performed using data collected with the CMS experiment in 2016 and 2017 at the LHC from pp collisions at centre-of-mass energies of 13 TeV.

        Speaker: Edward John Titman Scott  (Imperial College, Univ. of London)
      • 264
        Measurement of cross sections and properties of the Higgs boson in decays to two photons using the ATLAS detector

        Measurements of Higgs boson properties and cross sections measured in Higgs boson decays to two photons based on pp collision data collected at 13 TeV are presented.

        Speaker: Liza Mijovic (Edinburgh)
      • 265
        Measurements of Higgs boson production and properties in the ZZ decay channel using the CMS detector

        New results on the on-shell and off-shell Higgs boson production in proton-proton collisions at the LHC are presented. The properties of the Higgs boson are measured in the four-lepton final state using the latest dataset collected at center-of-mass energy of 13 TeV recorded by the CMS detector. The production cross section of the Higgs boson times its branching fraction to four leptons relative to the standard model expectation is measured and constraints on the main Higgs boson production modes are established. Joint constraints are set on the width and mass of the Higgs boson, as well as on the width and parameters that express its anomalous couplings to two electroweak vector bosons.

        Speaker: Toni Sculac (University of Split. Fac.of Elect. Eng., Mech. Eng. and Nav.Arc)
      • 266
        Measurement of cross sections and properties of the Higgs boson in decays to four leptons using the ATLAS detector

        Measurements of Higgs boson properties and cross sections measured in Higgs boson decays to four leptons based on pp collision data collected at 13 TeV are presented.

        Speaker: Oliver Kortner (Max-Planck-Institut fur Physik (DE))
      • 267
        Fiducial inclusive and differential Higgs boson cross sections at CMS

        The measurement of fiducial inclusive and differential Higgs boson cross sections allows the study of its properties under a minimal set of assumptions. By defining a fiducial phase-space, the uncertainties due to model dependence and extrapolations are minimized. A new, extended set of measurements performed using 35.9/fb of pp collisions collected by the CMS experiment at LHC in 2016 is presented. The measurements, obtained in the diphoton and ZZ decay channels, cover a wide range of differential observables, describing the kinematic properties of the Higgs boson, of its decay products and of particles produced in association with it. Fiducial measurements targeting individual production mechanisms are also presented.

        Speaker: Vittorio Raoul Tavolaro (ETH Zurich (CH))
    • Neutrino Physics: LBL (I) 202 (COEX, Seoul)


      COEX, Seoul

      Convener: Masashi Yokoyama
      • 268
        The ENUBET neutrino beam

        ENUBET has been designed to monitor lepton production in the decay tunnel of neutrino beams at single particle level and to provide a 1% measurement of the neutrino flux at source. In particular, the three body semileptonic decay of kaons monitored by large angle positron production offers a fully controlled nu_e source at the GeV scale for a new generation of short baseline experiments. The ENUBET Collaboration will present at ICHEP the first end-to-end simulation of the beamline and a complete review of the performance of this non-conventional technique. Special emphasis will be given to the new static focusing system that has been validated in 2018. Beyond positron monitoring, such scheme gives the opportunity to correlate in time the lepton at source and the neutrino at the detector. Time-coincidences 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 the positron tagger tested at CERN in 2017-2018 and the expected sensitivity of ENUBET for nu_e and nu_mu cross section measurements.

        Speaker: Francesco Terranova (Universita & INFN, Milano-Bicocca (IT))
      • 269
        Study of tau-neutrino production at the CERN SPS

        At the CERN SPS, the DsTau project has been proposed to study tau-neutrino production aiming at providing important information for future $\nu_\tau$ measurements. Precise measurement of the $\nu_\tau$ cross section would enable a search for new physics effects in $\nu_\tau$-nucleon CC interactions. It also has practical implications for neutrino oscillation experiments. The dominant source of $\nu_\tau$ is the sequential decay of $D_s$ mesons produced by proton interactions, whose uncertainty dominates current uncertainty in the $\nu_\tau$ cross section measurement. The project aims at reducing the systematic uncertainty from about 50% to 10% by measuring the $D_s$ differential production cross section. For this purpose, emulsion detectors with a nanometre-precision readout will be used to detect small kinks of the $D_s \rightarrow \tau$ decay. An emulsion detector has a position resolution of 50 nm, allowing for the detection of $D_s \rightarrow \tau \rightarrow X$ double kinks in a few mm range. Results from the beam tests in 2016-2017 will be presented together with a prospect for a pilot run in 2018 and a physics run in 2021.

        Speaker: Tomoko Ariga (Kyushu University)
      • 270
        Hadron Production Measurements for Neutrino Oscillation Experiments with NA61/SHINE

        The uncertainty in the flux of neutrino beams is dominated by our understanding of both the primary interactions of protons and the secondary interactions of protons, kaons and pions with target and beamline material. Hadron production measurements from a comprehensive set of interactions will allow modern neutrino experiments to make more precise neutrino cross section and oscillation measurements. Measurements of charged hadron spectra and total cross sections have recently been obtained by NA61/SHINE, a fixed target experiment at the CERN SPS, for a variety of beam particles, beam momenta and target materials. From the 2010 dataset of 31 GeV/$c$ protons interacting with a T2K replica target, multiplicities of $\pi^+$, $\pi^-$, $K^+$, $K^-$ and protons have been obtained. These measurements supplement the results from the 2009 thin target measurements, which have been used to constrain the T2K neutrino flux prediction. The application of the replica target results is ongoing and is expected to further reduce the uncertainties in the flux prediction. Starting in 2015 and continuing through 2018, NA61/SHINE has been recording interactions relevant to the neutrino beams at NuMI and LBNF located at FNAL. These beams are used by the ongoing experiments NO$\nu$A and MINER$\nu$A and the future experiment DUNE. In 2015, total inelastic and production cross section measurements have been obtained from interactions of $K^+$ at 60 GeV/$c$ and $\pi^+$ at 31 and 60 GeV/$c$ with carbon and aluminum targets. In 2016 and 2017, NA61/SHINE recorded interactions of $\pi^+$, $\pi^-$ and protons with momenta ranging from 31 to 120 GeV/$c$ with carbon, aluminum and beryllium targets. The first of these interactions to be analyzed is 60 GeV/$c$ $\pi^+$ with thin carbon and beryllium targets, where multiplicities of $\pi^+$, $\pi^-$, $K^+$, $K^-$ and protons are being measured. In the summer of 2018, NA61/SHINE will resume data taking including interactions of 60 GeV/$c$ $K^+$ with carbon and 120 GeV/$c$ protons on a NO$\nu$A replica target.

        Speaker: Scott Robert Johnson (University of Colorado Boulder (US))
      • 271
        Neutrino scattering at nuSTORM

        The nuSTORM facility will provide \nu_e and \nu_\mu beams from the decay of low energy muons confined within a storage ring. The instrumentation of the ring, combined with the excellent knowledge of muon decay, will make it possible to determine the neutrino flux at the %-level or better. The neutrino and anti-neutrino event rates are such that the nuSTORM facility serving a suite of near detectors will be able to measure \nu_eN and \nu_\muN cross sections with the %-level precision required to allow the next generation of long-baseline neutrino-oscillation experiments to fulfil their potential. By delivering precise cross section measurements with a pure weak probe nuSTORM may have the potential to make measurements important to understanding the physics of nucleii. The precise knowledge of the initial neutrino flux also makes it possible to deliver uniquely sensitive sterile-neutrino searches. The concept for the nuSTORM facility will be presented together with an evaluation of its performance. The status of the planned consideration of nuSTORM at CERN in the context of the Physics Beyond Colliders workshop will be summarised.

        Speakers: Kenneth Richard Long (Imperial College (GB)) , Patrick Huber (Virginia Tech)
      • 272
        Progress on the IsoDAR Antielectron Neutrino Experiment

        IsoDAR is a compact, accelerator-based source for anti-electron neutrinos produced through $^{8}$Li decay. When paired with a large scintillator-based detector, IsoDAR allows for a high-precision investigation of the reactor and source-based neutrino oscillation anomalies. This talk will discuss this physics, as well as other beyond Standard Model precision measurements that can be performed. We will also briefly review recent technical developments on the source.

        Speaker: Alejandro Diaz (Massachusetts Institute of Technology)
    • Quark and Lepton Flavor Physics: 5 102 (COEX, Seoul)


      COEX, Seoul

      Convener: Chris Parkes (University of Manchester (GB))
      • 273
        New results on semileptonic B decays and on the CKM magnitudes |Vub| and |Vcb| from Belle

        The magnitudes of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements |Vcb| and |Vub|, in combination with the angles of the Unitarity Triangle, are crucial for testing the quark flavour sector of the Standard Model. We report new results on |Vub| and |Vcb| obtained from the Belle data set. This presentation will also cover new measurements of B → pi pi l nu and B → D* * l nu. The analyses are based on the full data set recorded by the Belle detector at the Υ(4S) resonance containing 772 million BBbar pairs from e+ e- collisions produced by the KEKB collider.

        Speaker: Eiasha Waheed
      • 274
        Measurement of cos2beta = cos2phi_1 in B^0 to D^{(*)0} h^0 with D to K^0_S pi^+ pi^- decays by a time-dependent Dalitz analysis using BaBar and Belle combined data

        We report measurements of sin2beta = sin2phi_1 and cos2beta = cos2phi_1 from a time-dependent Dalitz analysis in B^0 to D^{(*)0} h^0 with D to K^0_S pi^+ pi^- decays using BaBar and Belle combined data sample containing 471 + 772 million B meson pairs collected at the Upsilon(4S) resonance. The measurement gives a confirmation of the CP violation in this B decay mode and solves the two-fold ambiguity of the angle beta=phi_1 that can not solely be fixed by the sin2beta = sin2phi_1 measurements in B^0 to charmonium K^0 decays.

        Speaker: Vitaly Vorobyev (Budker Institute of Nuclear Physics (RU))
      • 275
        Time-dependent CP violation measurements in B->DX decays at LHCb

        Time-dependent CP violation in B->DX decays provides sensitivity to angles of the CKM matrix. The excellent time resolution of the LHCb detector provides opportunities to perform precise time-dependent measurements. A summary of recent LHCb results are presented, including the B0->Dpi analysis which profits from the largest flavour tagged sample analysed by LHCb to determine the CKM angle sum (gamma+2beta).

        Speaker: Alex Birnkraut (Technische Universitaet Dortmund (DE))
      • 276
        Measurements of time-dependent CP violation in charmless B meson decays

        We report measurements of time-dependent CP violation in charmless B meson decays that are sensitive to physics beyond the Standard model or Kobayashi-Maskawa CP violation angle phi_2 in b to s penguin or b to u tree transitions, respectively. The analyses use Belle final entire data sample collected at the Upsilon(4S) resonance containing 772 mullion B meson pairs.

        Speaker: Insoo Lee (Hanyang University)
      • 277
        Recent improvements and prospects with flavour tagging at LHCb

        Precision measurements of time-dependent CP violation and of mixing parameters in the neutral B meson systems are bound to the ability to identify the production flavour of reconstructed b hadrons. The harsh environment of proton-proton collisions at LHC constitutes a challenging environment for flavour tagging and demand for novel and improved strategies. We present recent progress and new developments in flavour tagging at the LHCb experiment, which will allow for a further improvement of CP violation measurements in decays of B0 and Bs0 mesons.

        Speaker: Simon Akar (University of Cincinnati (US))
    • Strong Interactions and Hadron Physics: 5 101 (COEX, Seoul)


      COEX, Seoul

      Convener: Patrick Fritzsch (CERN)
      • 278
        First-principles lattice QCD calculation of the neutron lifetime

        There is an intriguing discrepancy in the measurements of the neutron lifetime. The almost 4$\sigma$ difference has recently been highlighted due to new high-precision experiments using ultra cold trapped neutrons and it could indicate the existence of new physics.
        Thanks to the Standard Model relation between the lifetime and the axial coupling $g_A$ of the neutron, which governs it's transition to a proton, a first-principle QCD calculation of $g_A$ could shed light on the experimental discrepancy and new physics.
        Lattice QCD provides a robust framework to numerically compute inherently non-perturbative quantities from first principles. Starting only from the Lagrangian of QCD and owing to new improved numerical algorithms, we calculate the axial coupling of the neutron with unprecedented precision and thus obtain the neutron lifetime: $\tau_n = 885(15)$ seconds.
        This calculation is challenging and the outcome is very promising: it paves the way to understanding nuclear observables directly from QCD degrees of freedom with high accuracy.

        Speaker: Enrico Rinaldi (Lawrence Livermore National Laboratory)
      • 279
        Lattice Predictions for Bound Heavy Tetraquarks

        We investigate the possibility of $qq^\prime \bar Q \bar Q^\prime$ tetraquark bound states using $n_f=2+1$ lattice QCD with pion masses $\simeq 164$, $299$ and $415$ MeV. Two types of lattice interpolating operator are chosen, reflecting first diquark-antidiquark and second meson-meson structure. Performing variational analysis using these operators and their mixings, we determine the ground and first excited states from the lattice hadron correlators. Using non-relativistic QCD to simulate the bottom quarks and the Tsukuba formulation of relativistic heavy quarks for charm quarks, we study the $ud\bar b \bar b$, $\ell s\bar b \bar b$ as well as $ud\bar c \bar b$ channels, with $\ell=u,d$. In the case of the $ud\bar b \bar b$ and $\ell s\bar b \bar b$ channels unambiguous signals for $J^P=1^+$ tetraquarks are found with binding energies $189(10)$ and $98(7)$ MeV below the corresponding free two-meson thresholds at the physical point. These tetraquarks are therefore strong-interaction stable, implying they are stable under strong as well as electromagnetic interactions while they can decay weakly. So far these are the first exotic hadrons predicted to have this feature. Further evidence for binding is found in the $ud\bar c \bar b$ channel, whereby the binding energy broadly straddles the electromagnetic stability threshold.
        Studying further the quark mass dependence, we vary the heavy quark mass in $ud\bar Q \bar Q$, $\ell s\bar Q \bar Q$ as well as $ud\bar Q \bar b$, $\ell s\bar Q \bar b$ between $\sim0.7$ and 6.3 times the bottom quark mass. The observed mass dependence closely follows a behaviour argued from phenomenological considerations of the heavy quark potential.

        Speaker: Anthony Sebastian Francis (CERN)
      • 280
        Charm Quark Mass with Calibrated Uncertainty

        We determine the charm quark mass $m_c(m_c)$ from QCD sum rules of moments of the vector current correlator calculated in perturbative QCD. Only experimental data for the charm resonances below the continuum threshold are needed in our approach, while the continuum contribution is determined by requiring self-consistency between various sum rules, including the one for the zeroth moment. Existing data from the continuum region can then be used to bound the theoretical error. Our result is $m_c(m_c) = 1272 \pm 8$ MeV for $\alpha_s(M_Z) = 0.1182$. Special attention is given to the question how to quantify and justify the uncertainty.

        J. Erler, P. Masjuan and H. Spiesberger,
        Charm Quark Mass with Calibrated Uncertainty,
        Eur. Phys. J. C 77, 99 (2017) [arXiv:1610.08531].

        Speaker: Jens Erler (IF-UNAM)
      • 281
        Contribution of QCD Condensates to the OPE of Green Functions of Chiral Currents

        In this talk, basic properties of QCD condensates will be presented, together with theirs relation to the operator product expansion (OPE) and the two-point and three-point Green functions constructed of chiral currents. Next, we will discuss our newest results for contribution of the QCD condensates with dimension D<6 to the Green functions calculated within the framework of chPT/RChT, i.e. chiral perturbation theory or resonance chiral theory. This matching of the OPE and such effective theories can lead to some coupling constants constraints and, therefore, thus allows us to obtain some unknown parameters of the chiral/resonance Lagrangian.

        Speaker: Mr Tomas Kadavy (Charles University)
    • 10:30 AM
      Coffee break
    • Accelerators: Physics, Performance, and R&D for Future Facilities: Accelerator Facilities 105 (COEX, Seoul)


      COEX, Seoul

      Convener: Daniel Schulte (CERN)
      • 282
        Storage ring proton Electric Dipole Moment Experiment with $10^{-29}\, e{\cdot \rm cm}$ sensitivity

        The electric dipole moment (EDM) of fundamental particles, when induced by the particle internal spin, violates separately the parity (P) and time (T) reversal symmetries. Due to CPT conservation, T-violation also means CP-violation and it is a sensitive probe of Physics beyond the standard model (SM).
        The storage ring EDM (srEDM) collaboration and the Juelich electric dipole investigations (JEDI) collaboration joined forces together with CERN scientists as part of the CERN initiative of Physics Beyond Colliders (PBC) to put together a study of the storage ring proton EDM method under the combined name charged particle EDM (CPEDM). The goal is to evaluate its feasibility, as well as to come up with a cost estimate for a ring with a goal of $10^{-29}\, e{\cdot \rm cm}$, making it the best sensitivity hadronic EDM experiment, with a mass-scale reach for new, SUSY-like Physics of order $10^3$ TeV.
        The method requires an all-electric storage ring between 400m-500m in circumference, simultaneous storage of counter-rotating, longitudinally polarized proton beams, magnetic field shielding below 10nT, state of the art SQUID-based beam position monitors, high efficiency with high analyzing power proton polarimeters, high precision beam/spin dynamics tracking simulators, and the development of reliable and cost effective electric field plates capable of sustaining 10MV/m with 3cm plate separation. Several polarimeter and beam polarization concepts have already been tested using polarized beams at the COSY ring in Juelich/Germany. I will present the current status towards the realization of this experiment.

        Speaker: Yannis Semertzidis (CAPP/IBS and KAIST in South Korea)
      • 283
        Design study of a Split-Coaxial RFQ for IsoDAR