The confirmation of excess in $R_{D^*}$ at the LHCb is an indication of
lepton flavor non-universality. Various different new physics operators
and their coupling strengths, which provide a good fit to $R_D$, $R_{D^*}$
and $q^2$ spectra, were identfied previously. In this work, we try to find
angular observables in $\bar{B} \to D^* \tau \bar{\nu}$ which enable us to distinguish between...
Pulsed beams have tremendous advantages for precision experiments with cold neutrons. In order to minimize and measure systematic effects, they are used at continuous sources in spite of the related substantial decrease in intensity. At the pulsed neutron source ESS, such experiments will gain up to a factor of 30 in event rate, and novel concepts become feasible. Therefore, the cold neutron...
The TCO-Asa is a 2015 established team of high-school students of the Liceo Scientifico T. Calzecchi Onesti, in Fermo (Italy), who built a detector instrumented by consumer components including a CMOS camera and a silicon photomultiplier readout by the open-source ArduSiPM kit, to study the Cherenkov effect in water.
The proposed poster presents the main activities of the students that...
Aging effects are studied for the CMS RPC system which can manifest during the HL-LHC running period. A dedicated consolidation program was set up using the CERN Gamma Irradiation Facility ++, where RPC detectors are exposed to a high gamma flux for a long term period equivalent to the HL-LHC operational time. Based on the past operational experience, the high background conditions are...
Lattice-QCD recent results and calculations of Daison-Schwinger equation by
C.Roberts et al. allowed to estimate the constituent quark mass
$M_q$ about 400~MeV. This is in agreement with the value 0f 441~MeV in the
modern constituent quark model (NRCQM, by L.Glozman et al.) where it is
determined as 1/3 of the mass of $\Xi$-octet hyperon.
Earlier the discreteness in mass values of...
Latest 13 TeV results of CMS searches for the Higgs boson produced in association with top quarks and decaying to b quarks will be presented. This poster will focus on the semi-leptonic and di-leptonic channels with the matrix element method, BDT and DNN discriminants.
The anarchy principle leading to the seesaw ensemble is studied analytically with
the usual tools of random matrix theory. The probability density function for the
seesaw ensemble of N × N matrices is obtained in terms of a multidimensional
integral. This probability density functions is then used to extract information
on the relevant physical parameters of the neutrino sector of a...
Anisotropic flow in heavy ion collisions is sensitive to the properties of produced hot and dense nuclear matter. In the present work, we will use a multi-phase transport (AMPT) model, with the default version and the version with string melting, to study the (pseudo)rapidity and pT dependence of anisotropic flow coefficients of charged hadrons and identified particles produced in heavy-ion...
Precision measurements by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV are presented based on $3.49 \times 10^5$ antiproton events and $2.42 \times 10^9$ proton events. At ~20 GV the antiproton-to-proton flux ratio reaches a maximum. Unexpectedly, above 60 GV the antiproton spectral index is consistent...
A study of feasibility of replacing a conventional phototube with an array of SiPMs is presented. High gain, low voltage operation and insensitivity to the magnetic field make SiPMs practically useful for the light collection in a physics experiment. In addition, sensors can be assembled in a compact system which is easily scalable. In this study an array of large area SiPMs was coupled...
ARIADNE is an ERC funded novel and innovative 1-ton two-phase LAr TPC experiment investigating photographic imaging as an attractive alternative readout method to charge readout that is currently planned for future giant two phase LAr neutrino experiments. Advantages over current readout techniques include reduction or elimination of charge read-out channels as well as ease of scalability,...
art@CMS is an education and outreach program of the CMS experiment at the Large Hadron Collider (LHC) at CERN, the European Laboratory for Particle Physics. It is based on the collaboration between the CMS and HEP scientific community, artists, art communities,as well as art and science teachers. The art@CMS scheme enacts as a master example within the HORIZON2020 initiative CREATIONS.
Since...
The large data samples at the High-Luminosity LHC will enable precise measurements of the Higgs boson and other Standard Model particles, as well as searches for new phenomena such as supersymmetry and extra dimensions. To cope with the difficult challenges such as large radiation doses and high pileup, during Phase II of the ATLAS upgrade the current Inner Detector will be replaced with a new...
Liquid Argon TPC (LArTPC) technology is increasingly prevalent in large-scale detectors designed to observe neutrino scattering events induced by accelerators or by natural sources. LArTPCs consist of a very high fraction of active detector material with spatial resolutions on the order of a few millimeters.
Three-dimensional interactions are imaged in multiple two-dimensional views by the...
Many Beyond Standard Model theories foresee the existence of heavy
resonances (>1 TeV) decaying in final states that include a high-energetic,
boosted jet and charged leptons or neutrinos. In these very peculiar
conditions, Monte Carlo predictions are not reliable enough to reproduce
accurately the expected Standard Model background. A data-Monte Carlo hybrid
approach (alpha method) has been...
The observation of Higgs boson production in association with a top quark pair allows the direct measurement of the top quark Yukawa coupling, a vital test to validate the Higgs mechanism within the Standard Model. The ATLAS search for this process relies on Boosted Decision Trees for Higgs reconstruction and signal-background discrimination. The employment of BDTs in the analysis of sqrt(s)=...
The poster will describe the development of new 3D and planar pixel detectors for the LHC Phase-2 upgrades, funded by INFN and made in collaboration by FBK foundry. The sensors, which are 100µm and 130µm thick n-in-p type, are assembled into hybrid single chip modules bump bonded to the PSI46dig readout chip. Results from beam tests performed at FTBF (Fermilab Test Beam Facility) obtained with...
Scientific developments have seen reality dissolved into smaller and smaller invisible particles that the physicist has to make visible. This process is mirrored by the artist attempting to express thoughts and emotions through the manipulation of materials in the case of fine arts, or the movements of the human body in the case of dance. Taking the same journey from something hidden to...
The features of B_d,s ->mumu decays are sensitive probes of physics beyond the Standard Model. This talk will review the results on these decays from the data collected by the CMS experiment in the second Run of LHC.
The calibration of the ATLAS b-tagging algorithm in environments characterised by large jet multiplicity is presented. The calibration uses reconstructed ttbar candidate events collected by the ATLAS detector in proton-proton collisions at 13 TeV, with a final state containing one charged lepton, missing transverse momentum and at least four jets. The b-tagging efficiencies are measured not...
A variety of algorithms have been developed to distinguish b-quark jets from jets containing only lighter quarks within the ATLAS experiment at the Large Hadron Collider (LHC). We describe the measurement of the false positive rate, i.e. the efficiency for the identification of jets arising from light quarks or gluons, for the algorithm most commonly used in ATLAS data analyses during the LHC...
There is no explanation in the Standard Model for the existence of families and for their mass hierarchy. It is possible to think to some horizontal symmetries between families and their spontaneous breakdown. Then new interactions will arise and compositeness limits must be respected. But the more stringent limits may arise from flavour changing neutral currents and CP-violation. However...
Belle II is a major upgrade of the Belle experiment, and will operate at the B-factory SuperKEKB, located at the KEK laboratory in Tsukuba, Japan. Belle II will be an ideal laboratory to study the properties of the charm quark, collecting more than 5x10^10 ccbar events with a total integrated luminosity of about 50 ab^-1 in the next decade.
We will discuss the expected sensitivity of Belle...
A study on the Gaseous Electron Multiplier (GEM) foil material is performed to determine the moisture diffusion rate & saturation level and the moisture effects on its mechanical properties. The study is focused on the foil contact with ambient air and moisture to determine the value of the diffusion coefficient of water in the detector polyimide. The presence of water inside the detector foil...
We report computations of the production cross-section of longitudinal electroweak boson pairs within Effective Field Theory for the Electroweak sector (including the Higgs). Particularly, we focuse on photon-photon production (in e-e+ as well as pp machines), as this is a very clean process allowing access to scalar and tensor resonances. We also employ LEP results on the oblique S,T...
Combined measurements of Higgs boson production cross sections and branching fractions are presented using the H->yy and H->ZZ->4l decay channels, based on 36.1 fb−1 of proton-proton collision data recorded by the ATLAS experiment at the LHC at sqrt(s)= 13 TeV. Results are presented for the individual production processes of gluon fusion, vector-boson fusion, WH, ZH, and ttH, and for kinematic...
The lightest pentaquark state recently observed by the LHCb collaboration, P(4380), is described with a compact multiquark approach. By using very general arguments, dictated by symmetry considerations, it is shown that this state belongs to an SU(3) flavour octet. A complete classi?cation of all possible states and quantum numbers, which can be useful both to the experimentalists in their...
We discuss a low energy $е^+е^-$ collider for production of the not yet discovered $\mu^+mu^-$ bound state (dimuonium). In our design we follow the Brodsky-Lebed proposal of the large-crossing-angle $е^+е^-$ intersection, when the dimuonium carries non-zero momentum and decays to $е^+е^-$ pair far apart from the beam collision region. The latter provides effective suppression of the Bhabha...
Recent $^8Be^*$ decay anomaly suggests the existence of a light dark boson which has a suppressed coupling to proton compared to its coupling to neutron. The simple dark $U(1)$ model constructed by introducing a kinetic mixing between standard model $U(1)_Y$ gauge boson and the dark boson needs to be generalized to satisfy the above requirement. The couplings of dark boson to standard model...
We present details of the new experimental detector systems for the g-2 experiment at FNAL. We present details of the beam delivery and storage ring at the new FNAL muon campus. In particular we concentrate on the construction of new calorimeters and calibrations system and the trackers . We discuss the status of the these detectors systems from testbeam and compare with results from the...
One of the open questions in the Standard Model is what the origin for the mass hierarchy and mixing of fermions is. The question, the so called "flavor problem", arises because in the lagrangian of the Standard Model the masses and mixing angles are completely arbitrary, their values are explained by ad hoc Yukawa couplings to fit the experimental data without giving a theoretical motivation...
The cross-section for top-quark pair production in association with a photon is measured in proton-proton collisions at the LHC at a center of mass energy of sqrt(s) = 8 TeV. The data with a total integrated luminosity of 20.2 fb-1 collected by the ATLAS detector in 2012 is used. The measurement is performed in the single lepton decay channel. The signal region is defined by the final state...
With ever increasing luminosity at the LHC, optimum online data selection is getting more and more important. While in the case of some experiments (LHCb and ALICE) this task is being completely transferred to computer farms, the others - ATLAS and CMS - will not be able to do this in the medium-term future for technological, detector-related reasons. Therefore, these experiments pursue the...
The SNO+ detector main physics goal is the search for neutrinoless double-beta decay, a rare process which if detected, will prove the Majorana nature of the neutrinos and provide information on the absolute scale of the neutrino absolute mass. Additional physics goals of SNO+ include the study of solar neutrinos, anti-neutrinos from nuclear reactors and the Earth's natural radioactivity as...
A novel higher-level flavour tagging algorithm called DL1 has been developed using a neural network at the ATLAS experiment at the CERN Large Hadron Collider. We have investigated the potential of Deep Learning in flavour tagging using higher-level inputs from lower-level physics-motivated taggers. A systematic grid search over architectures and the training hyperparameter space is presented....
The STEREO experiment was developed to confirm the hypothesis of a light sterile neutrino arising from the observed discrepancy between measured reactor antineutrino fluxes and revised flux predictions, known as the Reactor Antineutrino Anomaly. The detector is located at 10 m from the compact nuclear reactor core of the Institut Laue-Langevin, composed of >90% enriched 235U fuel. Antineutrino...
In 2014 CERN has started to organize “Beamline for Schools” (BL4S), an annual, worldwide physics competition for high school students. The students are invited to propose a particle physics experiment to CERN using a secondary beam of particles (electrons, protons, pions, kaons, muons) with momenta of up to 10 GeV/c. CERN also provides a number of different detectors that the students may use...
The Large Hadron-electron Collider LHeC and the Future Circular Collider in electron-hadron mode FCC-eh will provide electron-proton collisions with center-of-mass energies in the range 1.3-3.5 TeV and instantaneous luminosities larger than $10^{34}$ cm$^{-2}$s$^{-1}$. In this talk, we present new results on the precise determination of proton parton densities at both small and large x in...
The CT-PPS (CMS-TOTEM Precision Proton Spectrometer) project is a combined effort of the CMS and TOTEM collaborations to construct a detector with the purpose of studying central exclusive production (CEP) in proton-proton collisions. This poster describes the simulation and reconstruction code for the CT-PPS detectors implemented in CMS FastSim. The protons scattered from the collision at...
An electromagnetic calorimeter (ECAL) has been developed for the COMET experiment at J-PARC in Japan, which searches for muon-to-electron conversion of a charged lepton flavor violating process.
The observation of this process forbidden in the standard model (SM) gives a clear evidence of new physics beyond the SM.
The experiment aims at achieving a single event sensitivity of $10^{-17}$ by...
The J-PARC T59 experiment, named WAGASCI, is a neutrino detector with a water target, and it is planed to start taking the neutrino beam data from October 2017 at J-PARC neutrino beamline. Its goal is to measure the cross section ratio of charged current neutrino interaction on nucleus between water target and plastic target with the accuracy of a few percent. The detector adopts...
The COMET experiment searches for the muon-to-electron($\mu-e$) conversion with a sensitivity below $10^{-16}$ which is 10,000 times better than the present upper limit.
This process is strictly forbidden in the standard model because of the lepton flavor conservation law.
In contrast, its branching ratio can be sizable around $10^{-15}$ in many models of physics beyond the standard model...
We study the case of Dirac fermionic dark matter (DM). It is well known that the Dirac fermionic DM is seriously constrained from the experiment of spin-independ (SI) elastic cross sections with nuclei in the direct search. To evade the tree level interaction, the quantum numbers of the Dirac DM are taken to be $I_3=Y=0$. We find that there is a cancellation in one-loop diagrams, which reduces...
The analysis of direct dark matter (DM) detection data often relies on standard assumptions about the DM interactions with nucleons, namely the so-called spin-independent and spin-dependent interactions. However, other interactions are possible, each giving rise to a different signal. The rate spectrum experiments try to measure can thus be used to gain information about the DM properties. The...
Project Extreme Energy Events (EEE) – “La scienza nelle scuole” is an experiment dedicated to the study of high energy cosmic radiation, using detectors distributed over an area of more than half a million km2, from Geneva to Lampedusa. Data are taken simultaneously from about 40 telescopes. More than 40 billion particles have been registered up to now.
Project was born in 2004 from an idea of...
In the standard model neutrinos are massless left-handed fermions which very weakly interact with matter via exchange of the $W^\pm$ and $Z_0$ bosons. The development of our knowledge about neutrino masses and mixing provides a basis for exploring neutrino properties and interactions beyond the standard model (BSM). In this respect, the study of electromagnetic characteristics of massive...
An accurate calibration of the energy measurement of electron and photon is needed for many ATLAS physics analysis.
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....
Electron identification is a crucial input to many ATLAS physics analysis. The electron identification used in ATLAS for run 2 is based on a likelihood discrimination to separate isolated electron candidates from candidates originating from photon conversions, hadron misidentification
and heavy flavor decays. In addition, isolation variables are used as further handles to separate
signal and...
The Compact Linear Collider (CLIC) is an option for a future
electron-positron collider operating at centre-of-mass energies from a
few hundred GeV up to 3 TeV. Following an overview of precision
electroweak measurements possible at a high-energy electron-positron
collider like CLIC, details will be presented on two recent physics
benchmark analyses based on full detector simulations and...
Transverse momentum distributions of pions produced in relativistic nuclear collisions (p-p, Cu-Cu, Pb-Pb, Au-Au) at various energies including BES data are studied using Tsallis distribution as a parametrization. We will present the energy dependence and collision centrality of the Tsallis fit parameters, Tsallis temperature, volume and non-extensivity parameter, a parameter characterizing...
The Compact Linear Collider (CLIC) is a proposed high-energy, high-luminosity e+e- collider for physics studies and exploration up to the multi-TeV energy scale. We currently foresee building and operating CLIC in three sequential centre-of-mass energy stages at 380 GeV, 1.5 TeV, and 3 TeV. We will present an update of this energy-staging strategy and discuss the technical details of the...
To extend the LHC physics program, it is foreseen to operate the LHC in the future with an unprecedented high luminosity. To maintain the experiment's physics potential in the harsh environment of this so-called phase-2, the detector will be upgraded. At the same time the detector acceptance will be extended and new features such as a L1 track trigger will be implemented. Simulation studies...
We present results of a new analysis campaign, which combines the final data samples collected by the B factory experiments BaBar and Belle in single physics analyses to achieve a unique sensitivity in time-dependent CP violation measurements. The data samples contain $( 471 \pm 3 )\times 10^6\, B\bar{B}$ pairs recorded by the BaBar detector and $( 772 \pm 11 )\times 10^6\, B\bar{B}$ pairs...
Analyses searching for diboson resonances are very powerful tools to
investigate many beyond the Standard Model (BSM) scenarios such as extension of
the Higgs sector, Heavy Vector triplets (W’ and Z’) or excited states of
Gravitons. These searches exploit the many decay channels of the two bosons
allowing to select topologies with varied signal to background ratios and
statistics. Among these...
Since their invention, scintillator materials found many applications in physics. Several e.m. calorimeters in HEP, e.g. in CMS, Fermi and Gamma-400, use crystal scintillators with high-Z elements as CsI and PWO.
The impact of crystal orientation of scintillators is usually poorly considered, whereas in fact the influence of the crystalline structure on radiation and pair production in more...
Motivated by an anomaly observed in the decay of an excited state of Beryllium by the Atomki collaboration, we study an extension of the Standard Model with a gauged U(1)′ symmetry in presence of a 2-Higgs Doublet Model structure of the Higgs sector. We show that this scenario complies with a variety of experimental results and is able to explain the potential presence of a resonant spin-1...
The Extreme Energy Events (E.E.E.) experiment is a strategic project of Centro Fermi dedicated to the study of extreme energy cosmic rays. In particular it exploits a network of muon tracking telescopes constituted by three large area (2x2 vm^2) Multigap Resistieve Plate Chambers (MRPC). These detectors are used in many experiments due to its excellent efficiency and time resolution.
The...
Starting during the upcoming major LHC shutdown from 2019-2021, the ATLAS experiment at CERN will move to the the Front-End Link eXchange (FELIX) system as the interface between the data acquisition system and the trigger
and detector front-end electronics. FELIX will function as a router between custom serial links and a commodity switch network, which will use industry standard technologies...
We, the Institute for Basic Science Center for Axion and Precision Physics Research report the first axion dark matter search with toroidal geometry.
A toroidal geometry can provide several advantages, which are a larger volume for a given space and greatly reduced fringe fields which interfere with quantum noise limited superconducting amplifiers.
In this pioneering search, we exclude the...
The dynamics of isolated-photon plus jet production in pp collisions at sqrt(s) = 13 TeV were studied with the ATLAS detector at the LHC using a dataset with an integrated luminosity of 3.2 /fb. The photons were reconstructed for photon transverse energies larger than 125 GeV. The jets were identified using the anti-kt algorithm with radius parameter R=0.4 and selected in the rapidity...
The heavy quark doublet plays a central role in the quest for new physics. The complementary between studies of electroweak top quark production and bottom quark production is therefore intuitively clear and pointed out in the literature. Let us remind that the tension between the LEP measurement and the Standard Model prediction of the forward-backward asymmetry $A_{fb}^b$ is still one of the...
It is demonstrated that Gounaris-Sakurai model of the pion electromagnetic form factor is based on the P-wave iso-vector $\pi\pi$ scattering phase-shift given by a generalized effective-range formula of the Chew-Mandelstam type, valid exclusively only at the elastic region up to $1 GeV^2$. Therefore the Gounaris-Sakurai model is justified to be used in a determination of the $\rho(770)$ meson...
Hadronic signatures are critical to the high energy physics analysis program, and are broadly used for both Standard Model measurements and searches for new physics. These signatures include generic quark and gluon jets, as well as jets originating from b-quarks or the decay of massive particles (such as electroweak bosons or top quarks). Additionally missing transverse momentum from...
The transverse momentum spectra, $d^{2}\sigma/(d\eta dp^2_T)$, of charged hadrons produced in various high energy interactions ($pp$, $γp$, $γγ$, heavy-ion collisions) and measured in different experiments from ISR to LHC are considered simultaneously within several phenomenological models. As a result, the recently introduced "two component model" is shown to provide a much better description...
Australia has a rapidly growing high energy physics community members of which contribute broadly to outreach within the country and internationally. This talk will cover activities such as the Masterclass initiative which is being trialled by the government of New South Wales. With ongoing support from researchers who "meet" with the students via teleconference we are testing providing the...
We present an automatic procedure developed to reconstruct electromagnetic (EM) showers in the nuclear emulsions of the OPERA long baseline neutrino experiment.
OPERA was designed to investigate muon neutrino oscillations using so called Emulsion Cloud Chambers (ECC). Electronic detectors completed the ECC, where lead plates constituting the target mass were interleaved with nuclear emulsion...
HiSPARC (see http://www.hisparc.nl/en/) involves schools across Europe in real scientific research, and won the European Physical Society HEP outreach prize in 2007. It was born more than a decade ago in the Netherlands, with ongoing participation of over 100 schools. Relatively recently, HiSPARC has been introduced to UK, with a network of schools forming mainly in the Midlands/South West....
The associated production of the Higgs boson with top quarks (ttH) allows to constrain the top Yukawa coupling. This coupling is a key parameter of the Standard Model and its direct study through the ttH production mode is one of the most challenging in the ATLAS physics program at LHC.
An explorative analysis for this process has been performed using Run2 data recorded by the ATLAS detector...
Abstract: We present a search for dark matter particles produced in association
with a hadronically decaying W or Z boson. The analysis is performed with
36.5/fb of proton-proton collision data at a centre-of-mass energy of 13 TeV
recorded by the ATLAS detector at the Large Hadron Collider. With the full 13
TeV dataset and an increased signal acceptance, this result significantly
improves over...
Particle Physics Masterclasses are a successful tool to engage high-school students with high energy physics. Young people become scientists for one day and perform a tailor-made physics analysis involving real LHC data under the supervision of physicists. In this way students experience methods and tools used in research and gain an appreciation for fundamental science is created. The...
We propose a new method for calculating the dependences of the decay constants of heavy-light mesons on the light-quark mass $m$ based on QCD sum rules at infinitely large Borel mass parameter. For an appropriate choice of the correlation functions, all condensate contributions vanish and the $m$-dependence of the decay constants is shown to be mainly determined by the known analytic...
We present Jet Energy Calibration (JEC) measurements, based on a data sample collected in proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the CMS experiment at the LHC Run 2. The calibration is extracted from data and simulated events and employs combination of several channels and methods. It accounts successively for the effects of pileup, simulated jet response,...
KM3NeT is the next generation neutrino telescope. Cherenkov light from neutrino-induced secondary charged particles will be detected by an array of digital optical modules (DOM). A group of 18 DOMs, distributed in space along two thin ropes, constitutes the essential part of a 750 meters tall detection unit (DU). It is very hard to visualize in mind such a structure, despite many graphical...
Many exotics and SUSY models include particles which are long lived resulting in decays which are highly displaced from the proton-proton interaction point (IP). The standard track reconstruction algorithm used by the ATLAS collaboration is optimized for tracks from “primary” particles, which originate close to the IP. To this end, tight restrictions on the transverse and longitudinal impact...
The ATLAS Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment at CERN’s Large Hadron Collider. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium.
The light produced by the passage of charged particles is transmitted by wavelength shifting fibres to photomultiplier tubes (PMTs) located on the...
Muon beams of low emittance provide the basis for the intense, wellcharacterised
neutrino beams necessary to elucidate the physics of flavour at the
Neutrino Factory and to provide leptonantilepton
collisions up to several TeV at the Muon Collider. The international Muon Ionization Cooling Experiment
(MICE) will demonstrate muon ionization cooling, the technique proposed to reduce the...
The consistent simultaneous interpretation of pions and kaons both as bound states of quark and antiquark and as the (almost) massless boson states related, according to Goldstone’s theorem, to the dynamical (and explicit) breakdown of the chiral symmetries of QCD still represents a major challenge. Applying inversion to sufficiently simplified versions of the homogeneous Bethe–Salpeter...
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...
The status of $CP$ violations in charm sector is still unsettled.
According to SM, the predicted asymmetries are small, but often affected
by large uncertainties due to long-distance effects. However, it is
possible to build observables which SM predicts to be $CP$-conserving, so
that any measured asymmetry is undoubtedly a sign of New Physics. We
present the analysis of $CP$-asymmetries of...
Analysis of anisotropies in the arrival directions of galactic protons, electrons and positrons has been performed by the AMS on the International Space Station. An absolute anisotropy measurement has been performed with protons, electrons and positrons. These, together with the results of the anisotropy analysis of the electron to proton, positron to proton, and the positron to electron...
We present the first measurement of the direct CP-violating charge asymmetry in $B^\pm$ mesons decaying to $\mu^\pm D^{0} X$ where the $D^0$ decays to $K^+ \pi^-$, using $10.4\ \rm fb^{−1}$ of proton-antiproton collisions collected by the D0 detector during Run II at the Fermilab Tevatron Collider.
Utilizing powerful nuclear reactors as anti-neutrino sources, high mountains to provide ample shielding from cosmic rays in the vicinity, and functionally identical detectors with large target volume for near-far relative measurement, the Daya Bay Reactor Neutrino Experiment has achieved unprecedented precision in measuring the neutrino mixing angle $\theta_{13}$ and the neutrino mass squared...
The studies on the properties of Higgs boson in H->ZZ->4l (l = e, μ) and H->WW->eνμν decay channels based on the data collected with the CMS experiment in Run2 are presented. The reported results include studies of the Higgs boson production modes using H->ZZ and H->WW decay channels, as well as measurements of the Higgs boson mass, signal strength, fiducial differential cross sections for its...
Decays of the Z boson in the Standard Model violate parity, leading to a net polarization of the decay products. Z boson decays to pairs of tau leptons provide a unique opportunity to measure the tau polarization by using the kinematics of the subsequent tau decays, hence testing the Standard Model predictions. They also provide a unique opportunity to pioneer experimental techniques that...
The dijet production cross section for jets containing a b-hadron (b-jets) has been measured in
proton--proton collisions with a centre-of-mass energy of 7 TeV, using the ATLAS
detector at the LHC. The data used correspond to an integrated luminosity of 4.2/fb.
The cross section is measured for events with two identified b-jets with a transverse
momentum pT > 20 GeV. At least one of the jets...
In this poster we present measurements of normalized differential top quark pair (ttbar) production cross sections using final states with two leptons (ee, mumu, and emu) in proton-proton collisions at sqrt(s) = 13 TeV at the CERN LHC. The data were recorded in 2015 with the CMS detector and correspond to an integrated luminosity of 2.2 fb−1. The ttbar production cross section is measured as a...
Measurements of low-energy $e^+e^-$ hadronic cross sections are of fundamental importance because of the approximately three sigma discrepancy between the current measured value of the muon anomalous magnetic moment (g-2) and the Standard Model prediction.
By means of the initial-state-radiation technique, we present the first measurements of the $e^+e^- \to K_S K_L \pi^0$, $K_S K_L \eta$ ...
This poster presents the measurement of the inclusive top-quark pair-production cross-section in the lepton+jets channel with 20.2 fb-1 of 8 TeV data collected with the ATLAS detector at the LHC, using a neural-network discriminant and the reconstructed mass of the hadronically decaying W boson. Events are selected by requiring at least four jets, where at least one of the jets is required to...
Tau leptons play an important role in many Standard Model and Beyond the Standard Model physics processes that are being investigated at the LHC. This poster details measurements of the performance of the reconstruction and identification of hadronic tau lepton decays using the ATLAS detector. The measurements include the performance of the identification, trigger, energy calibration and...
Charm quarks possess large masses and thus they are expected to be primarily produced at the initial stages of heavy-ion collisions. Hot and dense nuclear matter, usually referred to as the Quark-Gluon Plasma (QGP), can also be created in these collisions. Therefore, the QGP can be studied using charm quarks as penetrating probes via the in-medium energy loss, which is deeply related to the...
A measurement of the inclusive and differential fiducial cross section of Higgs-boson production in the four lepton (electrons or muons) final state
is presented. The data sample, collected by the ATLAS experiment in 2015
and 2016, corresponds to an integrated luminosity of 36.1 fb$^{-1}$ of
proton-proton collisions produced at the Large Hadron Collider at a
centre-of-mass energy of 13 TeV....
The Skyrme Model is considered a natural candidate for a low-energy effective theory of QCD, a point of view supported by results coming from 1/N_c expansion and holographic QCD. This framework leads to an attractive picture where baryons (and nuclei) emerge as topological solitons with a topological number identified to the baryon number A. Unfortunately, even the most naive Skyrme Model...
The major goals of the NICA/MPD Project is the study of the in-medium properties of hadrons and the nuclear matter equation of state, including a search for possible signals of decofinement and/or chiral symmetry restoration phase transitions and the QCD critical endpoint in the region of the collider energy √sNN = 4 - 11 GeV. The basic strategy is to measure a large variety of signals...
Muon reconstruction and identification play a fundamental r
ole in many analyses of
central importance in the LHC run-2 Physics programme.
The reconstruction algorithms and identification criteria
used in ATLAS in the analyses
of pp collision data at
√
s
= 13
TeV are presented.
Their performances are measured in data based on the decays o
f Z and J
ψ
to pair of
muons, that provide a large...
If neutrinos are Dirac fermions, certain new physics beyond the standard model should exist to account for the smallness of neutrino mass. With two additional scalars and a heavy intermediate fermion, we systematically study the general mechanism that can natrally generate the tiny Dirac neutrino mass at tree and in one-loop level. For tree level models, we focus on natural ones, in which the...
Electromagnetic properties of massive neutrinos [1] and their effects on neutrino oscillation phenomena are brought into focus. The searches for neutrino millicharges, charge radii and magnetic moments in astrophysics and laboratory measurements are outlined [2,3]. Prospects of probing these neutrino characteristics with JUNO are discussed.
[1] C. Giunti and A. Studenikin, *Neutrino...
The origin of neutrino oscillations phenomena emerges due to coherent superposition of different neutrino states. Such superposition can be destroyed by quantum decoherence that appears from entanglement of neutrino
with environment. This quantum decoherence can cause suppression of different neutrino oscillations. In this work we study suppression of neutrino-antineutrino oscillations as a...
It was shown for the first time in [1] (see also [2,3]) that neutrino spin (and spin-flavor) precession can be engendered not only by neutrino interaction with the transversal magnetic field but also by neutrino interaction with matter
when there is a transversal matter current or matter polarization. Recently this effect has attracted reasonable interest within studies of neutrino fluxes from...
SoLid is a reactor neutrino experiment, located at BR2@SCK-CEN (Mol, Belgium), searching for very-short baseline neutrino oscillation (~ 10 m). Its main objectives are to confirm the so-called Reactor Antineutrino Anomaly (RAA), and to test in-fine the existence of light sterile neutrino(s). This experiment is based on a new kind of neutrino detector specially designed against background. The...
Neutrons induced by cosmic-ray muons are a significant background for underground experiments studying neutrino oscillations, neutrino-less double beta decay, dark matter and other rare-event signals. The Daya Bay Reactor Antineutrino experiment consists of 8 antineutrino detectors (AD) placed in three experimental halls at different baselines from six nuclear reactors. Each AD contains 20...
In preparation for the High Luminosity LHC, GEM detectors will be installed during Long Shutdown 2 (2018-2019) in the forward region of 1.6 < |eta| < 2.2 to improve trigger and tracking performance in the muon endcap, and maintain sensitivity to low pT muons. During the 2016-2017 year-end technical stop, five pairs of triple-foil GEM detectors were installed on the minus endcap of CMS as a...
Our presentation will be based on our recent paper [1].
We construct a new, simple model of the heavy ion collision.
This model is local in the impact parameter plane and appropriate for the SPS
energy range. It can be regarded as a new realization of the ``fire-streak'' approach, originally applied to studies of lower energy nucleus-nucleus reactions.
Starting from local energy and momentum...
We demonstrate explicitly that the $f^F,f^D,f^S$ coupling constants in the SU(3) invariant interaction Lagrangian of the vector-mesons with $1/2^+$ octet baryons does not depend on the choice of the $\omega-\phi$ mixing configuration.
The use and advantages of Receiver operating characteristic (ROC) curve for a binary classification is discussed in the context of a high energy physics classification problem. In particular, we look into the crucial task of obtaining the optimal cutoff or operating point using the curve for a multidimensional data and propose a novel method to obtain it. The results are illustrated using a...
The coherent inelastic processes of the type $a \rightarrow b$, which may take place in the interaction of hadrons and $\gamma$ quanta with nuclei at very high energies (the nucleus remains the same), are theoretically investigated. For taking into account the influence of matter inside the nucleus, the optical model based on the concept of
refraction index is applied. Analytical formulas for...
Recently, there was a controversy about the calculation of loop corrections to $H \to\gamma \gamma$ and $g g \to H$, which are very relevant decay and production channels for the Higgs boson at the LHC. The fact that these corrections are both IR and UV finite is not enough to perform the calculation without a proper regularization of the intermediate steps. In this talk, we apply the...
In Run 2 at CERN's Large Hadron Collider, the ATLAS detector uses a two-level trigger system to reduce the event rate from the nominal collision rate of 40 MHz to the event storage rate of 1 kHz, while preserving interesting physics events. The first step of the trigger system, Level-1, reduces the event rate to 100 kHz with a latency of less than 2.5 μs. One component of this system is the...
The identification of b-quark initiated jets (b-tagging) is a fundamental tool for the physics of ATLAS. Such jets can be discriminated from those produced by the hadronization of light and charm quarks based on characteristic properties of B hadrons, such as the long lifetime and the hard fragmentation function. The algorithms are based either on the identification of tracks displaced from...
The protoDUNE Single Phase (protoDUNE-SP) TPC is a prototype for the DUNE far detector and it is currently under construction at CERN. It will not only serve as a test-bed for the engineering design and construction techniques but will also provide a set of key measurements for the future DUNE far detector.
The new H4 extension beam-line at CERN will provide electron, muon and hadron beams...
Jets and missing transverse energy are key elements in both precision measurements and searches for new particles at LHC. Improved jet momentum resolution and pile-up stability of jet energy and missing transverse energy measurements are highly desirable in the high pile-up conditions expected in the next years of LHC. A particle flow algorithm, which combines measurements from both the...
The Monte Carlo setups used by ATLAS to model boson+jets and multi-boson
processes at $\sqrt{s}$ = 13 TeV in $pp$ collisions are described. Comparisons between data and several events generators are provided for key kinematic distributions. Issues associated the evaluation of systematic
uncertainties are also discussed.
The characterisation of the Higgs boson discovered in 2012 around 125 GeV, and confirmed with the data collected in Run II, requires the precise determination of its mass, width and couplings. The electromagnetic calorimeter (ECAL) of the Compact Muon Solenoid Experiment (CMS) is crucial for measurements in the highest resolution channels, H->gamma gamma and H->4 leptons. In particular the...
The Level-1 Muon Barrel Trigger is one of the main elements of the event selection of the ATLAS experiment at the Large Hadron Collider. It exploits the Resistive Plate Chambers (RPC) detectors to generate the trigger signal. The RPCs are placed in the barrel region of the ATLAS experiment: they are arranged in three concentric double layers and operate in a strong magnetic toroidal field. RPC...
Good photon identification capabilities are important for many aspects of the ATLAS physics program, from
Higgs boson measurements to new physics searches. The identification of prompt photons and the rejection
of background coming mostly from photons from hadron decays relies on the high granularity of the ATLAS calorimeter.
Several methods are used to measure with data the efficiency of the...
he High Luminosity-Large Hadron Collider (HL-LHC) is expected to start in 2026 and to provide an integrated luminosity of 3000 fb-1 in ten year, a factor 10 more than what will be collected by 2021.
This high statistics will allow to perform precise measurements in the Higgs sector and improve searches of new physics at the TeV scale.
The luminosity needed is L ~7.5 1e34 cm-2 s-1,...
The general consequences of $T$ invariance for the direct
and inverse binary reactions $a + b \rightarrow c + d$ ,
$c + d \rightarrow a + b$ with spin-1/2 particles $a$, $b$
and unpolarized particles $c$, $d$ are analyzed.
Using the formalism of helicity amplitudes, the theoretical study of polarization
effects in the reaction $p + \,^{3}{He}
\rightarrow \pi^{+} + \,^{4}{He}$ and in the...
Spin correlations for the $\Lambda\Lambda$ and
$\Lambda\bar{\Lambda}$ pairs, produced in relativistic heavy-ion collisions, and related angular correlations at the joint registration of space-parity nonconserving hadronic decays
of two hyperons are theoretically analyzed. These correlations give important information about the character and mechanism of multiple processes, and the advantage of...
We present the precise monthly time variation of the e+, e-, p and He fluxes by the Alpha Magnetic Spectrometer on the International Space Station. The data were collected during the ascending phase of solar cycle #24 through its maximum and toward its minimum. This covers one half solar cycle. For the ?first time, the time evolution of cosmic rays of opposite charges and different mass and...
The neutrino mass hierarchy is one of the neutrino fundamental properties yet to be determined. We introduce a method to determine neutrino mass hierarchy by comparing the events of neutral current (NC) interactions, $\nu(\overline{\nu}) + p\rightarrow\nu(\overline{\nu}) + p$, and inverse beta decays (IBD), $\bar{\nu}_e + p\rightarrow n + e^+$, of supernova neutrinos from accretion and cooling...
For several years, a team of 20 scientists from ESRF, IPHC Strasbourg, IPN Lyon and LPSC Grenoble has been working to study the detection properties of large-size diamond detectors from several suppliers, with the aim of achieving reliable & efficient sensors for particle tracking or medical applications. High radiation hardness and intrinsic electronic properties make diamonds reliable & very...
Antimatter nuclei in cosmic rays (CRs) represent a promising tool for the indirect search of dark-matter particles in the Galaxy.
At this conference, we report updated calculations for the astrophysical production of CR antiproton, antideuteron, and antihelium nuclei using updated cross-section formulae and new astrophysical constraints inferred from the recent AMS-02 data on CR protons and...
The Feedback On Nanosecond Timescales (FONT) Group has developed low-latency beam feedback systems for providing bunch-by-bunch beam position correction capability for Linear Colliders. Prototype feedbacks have been deployed and tested at the KEK ATF2 facility, where they have been extended for use in stabilising the vertical position of the electron beam in the upstream and interaction-point...
Precision measurements by AMS of fluxes and flux ratios of charged elementary particles in cosmic rays are presented. In the absolute rigidity range ∼60 to ∼500 GV, the antiproton, proton, and positron fluxes are found to have nearly identical rigidity dependence while the electron flux exhibits a different rigidity dependence. Below 60 GV, the antiproton-to-proton, antiproton-to-positron, and...
This poster presents the latest measurements of the Higgs boson properties measured in the H → γγ decay channel using 36.1fb −1 of proton-proton collision data taken at √ s = 13TeV by the ATLAS experiment at the LHC. Fiducial and differential cross section measurements are presented in a variety of phase space regions and as a function of several kinematic variables, to be compared with the...
The prospects for particle-physics experiments based on an AWAKE-like electron acceleration scheme will be reviewed. These include high energy electron test beams, searches for very weakly interacting particles in fixed target experiments as well as electron-proton and electron-ion colliders covering a wide range of energies up to a very high energy electron-proton (VHEeP) collider with...
The role of quantum groups, a particular class of Hopf algebras, as describing the fundamental symmetries of the Standard Model is investigated. Using the quantum group SUq(3) as a flavour symmetry leads to exceptionally accurate baryon mass sum rules that agree perfectly with experimental data and magnetic moments that agree significantly better with experimental data.
The consideration of...
With the experimental evidences of $\overline B {}^0\to p \overline{p}$ and $B^-\to\Lambda\overline p$ decays, it is now possible to extract both tree and penguin amplitudes of the charmless two-body baryonic $B$ decays for the first time. The extracted penguin-tree ratio agrees with the expectation. Using the topological amplitude approach with the experimental results on $\overline B {}^0\to...
At LHC, the design luminosity, 1034 cm-2 s-1, has already been reached during Summer 2016. LHC is planning, in the short term future, to further enhance the luminosity, resulting in a higher trigger frequency and an increased pileup. These factors constitute a challenge for the data readout since the rate of data to be transmitted depends on both pileup and trigger frequency. In the ATLAS...
In the framework of the Masterclass of particle physics in Pisa, each year a questionnaire is given to the students to assess if the Masterclass met a positive response.Together with specific questions about the various activities they took part in during the Masterclass day, we ask them if they would like to become a scientist. They are offered 15 possible motivations for a “yes” or a “no” to...
The $P'_5$ and $R_K$ anomalies, recently observed by the LHCb collaboration in
$B \to K^{(*)}$ transitions, may indicate the existence of a new $Z'$ boson,
which may arise from gauged $L_\mu - L_\tau$ symmetry. Flavor-changing neutral current $Z'$ couplings, such as $tcZ'$, can be induced by the presence of extra vector-like quarks. In this paper we study the LHC signatures of the induced...
The latest results of the search for a high mass scalar boson using the 13TeV proton-proton collision data acquired by the CMS experiment in 2016 will be presented. In particular, this poster will be focused on the decay channel H->ZZ->llvv selected from data corresponding to an integrated luminosity of 35.9/fb. An analysis of the reconstructed transverse mass and missing transverse energy is...
A wide search program is being carried on at the LHC under the hypothesis that Dark Matter (DM) consist of weakly interacting massive particles (WIMPs). Final states with heavy flavour quarks and large momentum imbalance represent an interesting discovery signature which allows to probe models with scalar or pseudoscalar interactions between the Standard Model and the Dark Sector under the...
The existence of Dark Matter is inferred from several astrophysical and
cosmological observations. Several extensions of the Standard Model
accommodating Dark Matter constraints predict associated production of Dark
Matter particles with the Standard Model Higgs boson. Such models are searched
for in final states with large missing transverse momentum and a Higgs boson
decaying to a pair of...
Supersymmetry is one of the most motivated Standard Model extensions. Despite the meticulous search during the LHC Run I, there is no evidence supporting this theory. Starting from 2015, LHC is performing a second data taking run with a higher center of mass energy (13 TeV), providing a great occasion for the search of beyond the Standard Model physics. New results obtained with the 2015-2016...
Several possible extensions of the Standard Model predict the existence of a dark sector that is weakly coupled to the visible one: i.e. the two sectors couple via the vector portal, where a dark photon with mass in the MeV to GeV range mixes kinetically with the SM photon. If the dark photon is the lightest state in the dark sector, it will decay to SM particles, mainly to leptons and...
Supersymmetry is able to solve a number of questions the celebrated standard model of particle physics has left unresolved. Particle collision experiments such as CMS, located at the CERN LHC, perform searches for the existence of supersymmetry in proton-proton collisions in a variety of different final states. In this poster, the results of the search for electroweak production of SUSY in...
This poster presents the results of a search for gluinos and squarks in events with exactly one lepton in the final state in addition to multiple jets and large missing transverse momentum. The analysed ATLAS data from 2015 and 2016 corresponds to an integrated luminosity of 36.1 fb$^{-1}$ at a centre-of-mass energy of 13 TeV. In addition to previous publications the latest results contain a...
A search for heavy pseudoscalar ($A$) and scalar ($H$) Higgs
bosons decaying into a top-quark pair ($t\bar{t}$) has been performed in
20.3~fb$^{-1}$ of data collected by the ATLAS experiment at the Large
Hadron Collider in proton--proton collisions at a center-of-mass energy of
$\sqrt{s} = 8$~TeV. No significant deviation from the Standard Model
expectation is observed in the $t\bar{t}$...
A search for new high mass resonances which decay to two high-$p_{\rm T}$
leptons with same-sign charge is presented. The results reported here use the
\textit{pp} collision data sample corresponding to 36.5 fb$^{-1}$ of integrated
luminosity collected in 2015 and 2016 by the ATLAS detector at the LHC with a
centre-of-mass energy of 13 TeV. The search considers the pair production of a
doubly...
Several supersymmetric models predict the production of massive long-lived supersymmetric particles. Such particles, if charged, may be detected through abnormal specific energy loss or long time-of-flight to the calorimeters. The poster presents recent results from searches of long-lived supersymmetric charged particles using proton-proton collisions at a centre of mass energy of 13 TeV with...
A search for long-lived, massive particles, as generically predicted
by many theories beyond the Standard Model, is presented. The search
targets final states with large missing transverse momentum and at
least one high-mass displaced vertex with five or more tracks, and
used 32.7 fb−1 of √s=13 TeV pp collision data collected by the ATLAS
detector at the LHC. The observed yield is consistent...
The latest results of the search for MSSM Higgs boson decaying into two tau leptons with the full 2016 data will be presented. The analysis is performed using the dataset recorded by the CMS experiment at the LHC from pp collisions at centre-of-mass energies of 13 TeV corresponding to an integrated luminosity of 35.9/fb.
The COMET Experiment at J-PARC aims to search for the lepton-flavour-violating (LFV) process of muon-to-electron conversion in a muonic atom, $\mu^{-}N\rightarrow \mathrm{e}^{-}N$, with a branching-ratio sensitivity of $6\times 10^{-17}$, which is 4 orders of magnitude better than the present upper limit.
Complemental searches for two kinds of muon LFV decay modes, $\mu^{+}\rightarrow...
Many well established models extending beyond Standard Model (e.g. Grand Unified Theory, Sequential Standard Model or models proposing extra spatial dimension(s)) predict the existence of new heavy neutral bosons that would decay in two leptons. A search for new narrow resonances, generically referred as Z', in the dimuon decay channel has been performed using data collected by the CMS...
New high-mass scalar states decaying into two photons are predicted in many extensions of the Standard Model. The diphoton final state provides a clean experimental signature with excellent invariant mass resolution and moderate backgrounds.
A search for such states with masses above 200 GeV is presented here, using 37 fb-1 of data collected by the ATLAS experiment in 2015 and 2016 at...
A search for new phenomena in ttbar final states with additional heavy-flavour
jets has been carried out using 36.1 fb-1 data of pp collisions at sqrt(s) = 13
TeV with the ATLAS detector at the LHC. The search targets a variety of signals,
including the pair production of a vector-like top quark; four-top-quark
production in several new physics scenarios. Data are analysed in...
Permanent electric dipole moments (EDMs) of fundamental particles provide powerful probes for physics beyond the Standard Model. We propose to search for the EDM of strange and charm baryons at LHC, extending the ongoing experimental program on the neutron, muon, atoms, molecules and light nuclei. The EDM of strange $\Lambda$ baryons, selected from weak decays of charm baryons produced in $pp$...
Narrow resonances decaying into $WW$, $WZ$ or $ZZ$ boson pairs are searched for
in 37.1 fb$^{-1}$ of proton-proton data at a centre-of-mass energy of
$\sqrt{s}=13$TeV recorded with the ATLAS detector at the Large Hadron Collider
in 2015 and 2016. The diboson system is reconstructed using pairs of
high-$p_{\mathrm{T}}$ large radius jets tagged as compatible with the boosted
hadronic decay of a...
This poster presents the run 2 search for di-Higgs production in the yybb channel. In the Standard Model, this process provides a lens on the Higgs self-coupling and it is enhanced, resonantly or non-resonantly, in many extensions to the SM. It is appealing thanks to a clean diphoton trigger, relatively small backgrounds, and excellent diphoton mass resolution. It is also particularly...
During Run-1 of the Large Hadron Collider, a particle consistent with the Standard Model Higgs boson was observed coupling directly to the leptonic and bosonic sectors of the Standard Model. The decay of the Standard Model Higgs to bbbar is the most commonly occurring decay mode, with a branching fraction of approximately 58%. Probing this decay is vital to furthering our understanding of the...
Models with compressed mass spectra target a very interesting region of the SUSY parameter space and are very well motivated by theoretical considerations, such as dark matter constraints and naturalness. The presented analysis focuses on signal events containing a single low-momentum lepton and moderate missing transverse energy. The search targets a simplified model in which the signal...
A search for photonic signatures of various generalised models of gauge-mediated supersymmetry breaking is presented at proton--proton collisions at a centre-of-mass energy of 13 TeV. The results are based on an integrated luminosity of 36.1 fb-1 recorded by the ATLAS detector at the LHC. Different experimental signatures incorporating one or more isolated photon and significant missing...
We present searches for supersymmetry in the all-hadronic final state using a customized top tagger. The focus of the studies is on the direct pair production of third-generation squarks. The analysis is performed using the data set recorded by the CMS
experiment at the LHC in pp collisions at a center-of-mass
energies of 13 TeV, with an integrated luminosity of 35.9 1/fb.
The results are...
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+−0.6)% , and the sum of exclusive baryonic channels, averaged on neutral and positive B mesons at less than 1%,...
The Yukawa coupling of the Higgs boson to the top quark is a key parameter of the Standard Model. It can be constrained using the associated production process pp → ttH + X.
A search for this process using final states with multiple leptons, primarily targeting the decays H→ WW∗ and H → ττ, has been performed using the data set recorded by the ATLAS detector in 2015 and 2016 at a center of...
In 2012, the ATLAS and CMS Collaborations announced the discovery of a new state with a mass around 125 GeV, compatible with the Standard Model Higgs boson. The measurements of this new particle’s properties, in particular its couplings to other elementary particles, are important to test the predictions of the Standard Model.
In this poster, the coupling of the Higgs boson with beauty quarks...
Charged lepton flavour violating processes are unobservable in the standard model,
but they are predicted to be enhanced in several new physics extensions.
Data collected with the BaBar detector at the SLAC PEP-II $e^+e^-$ collider
at a centre-of-mass energy of 10.36 GeV were used to search for electron-muon
flavour violation in $\Upsilon(3{\mathrm{S}}) \to e^{\pm}\mu^{\mp}$ decays.
The...
A search for the standard model Higgs boson is presented in the Vector Boson Fusion production channel with decay to bottom quarks. A data sample comprising 35.9 fb^−1 of proton-proton collision at sqrt(s) = 13 TeV collected during the 2016 running period has been analyzed. Production upper limits at 95% Confidence Level are derived for a Higgs boson mass of 125 GeV, as well as the fitted...
We discuss a search for a time-varying $\bar{v}_{e} → \bar{v}_{e}$ oscillation probability and Lorentz violation at the Daya Bay Reactor Neutrino Experiment in the framework of the Standard Model Extension (SME). The experiment’s unique configuration of multiple baselines to three groups of nuclear reactors allows to constrain individual Lorentz-violating coefficients for the first time. In...
Supersymmetry (SUSY) still remains one of the most interesting theories which are candidates to describe physics beyond the Standard Model, even if the latest Run1 results and interpretations have so far shown no experimental evidence for the existence of superparticles. If SUSY exists, the strong production of coloured SUSY particles is expected to be the dominant production process at the...
Although no experimental evidence has been found during LHC Run1, supersymmetry (SUSY) remains one of the most promising and motivated Standard Model extensions. Focusing the attention on its minimal formulation, the Minimal Supersymmetric Standard Model (MSSM), where the multiplicative quantum number R-parity is conserved, the latest results in searching for pair production of top squarks...
Natural supersymmetry suggests a relatively light top squark, which is the supersymmetric partner of the top quark, with a mass that might be within the discovery reach of the LHC.
A search for direct top squark pair production, in final states with one isolated electron or muon, multiple jets and missing transverse momentum, is presented. The analysis is performed using data from...
One of the most important parameters in supersymmetry is the mass of the supersymmetric partner of the third generation quarks. The scalar top quark mass lighter than 1 TeV is favored in many theories, but no evidence has not been found in the previous searches. Therefore the search needs to be performed more extensively considering various LSP scenarios with increased integrated luminosity....
The associated production of the Higgs boson with a pair of top/anti-top quarks (ttH) is the only process providing the direct access to the measurement of the Yukawa coupling between the Higgs boson and the top quark. The presented results exploit the data collected during 2015 and 2016 by the ATLAS experiment during LHC collisions at a center-of-mass energy of 13 TeV. Multivariate...
Searches in CMS for dark matter in final states with invisible particles recoiling against leptons and photons are presented. Various topologies are explored, covering several specific dark-matter production modes. The talk focuses on the recent results obtained using data collected in the 2016 run of the LHC.
This poster presents the results from the Mono-Higgs analyses performed with the CMS experiment at the LHC using the full 2016 data set. The results are interpret in canonical Dark Matter models.
Recent results on searches for exotic production and decays of the Higgs boson H(125) are presented. The current status of the searches for invisible and quasi invisible decays, lepton flavour violation (emu, etau, mutau) decays, decays to light scalars will be reviewed.
A lot of progress on the study of the properties of the Higgs boson has been made since its discovery, however little is still known about the Higgs boson couplings to light quarks. Direct measurements of the Higgs boson decays to pairs of light-quarks are challenging due to the overwhelming hadronic backgrounds. A new window to experimentally access these couplings opens through the search...
We propose to look for the light CP-odd state through the decay $h \to P\ell^+\ell^-$, where P stands for a pseudoscalar quarkonia. We show that the corresponding branching fraction can be enhanced as much as by a factor ~20-30 in the models with two Higgs doublets of Type I, II or X. In this study we consider $m_A < m_h$ but larger than ~20 GeV. We then show a special case of a very light...
Weak heavy mesons decays are candidate processes for new physics manifestation. Their theoretical description requires an appropriate treatment of hadronic effects. Because of their non-perturbative nature, they are usually treated in some model-dependent way. Focusing on several weak heavy mesons decays, we will present the confined covariant quark model and demonstrate its features. Our...
How much information is added to the Review of Particle
Physics when a new decay branching ratio of a hadron is measured and
reported? This is quantifiable by Shannon's information entropy. It may
be used at two levels, the distribution of decay-channel probabilities,
and the distribution of individual quantum-state probabilities
(integrating the later provides the former). We illustrate...
The resistive micromegas detectors have already proved to be suitable for precision tracking in dense particle rate environment up to few kHz/cm2. Rate capability up to few MHz/cm2 and low occupancy can be achieved by using few mm2 readout pads. Such a rate capability will be required in upgrades of forward muon detectors of LHC experiments as well as in experiments at future colliders.
We...
We show that observations of solar $\gamma$-ray fluxes offer a novel probe of dark matter, in scenarios where interactions with the visible sector proceed via a long-lived mediator. As a proof of principle, we demonstrate that there exists a class of models which yield solar $\gamma$-ray lines observable with the next generation of $\gamma$-ray telescopes, while being allowed by a large...
The Spin Light of Neutrino (SLν) is a new possible mechanism of electromagnetic radiation by a massive neutrino (with nonzero magnetic moment) moving in media [1]. Although this effect is strongly suppressed due to smallness of neutrino magnetic moment, for ultra-high neutrino energies, for instance for PeV neutrino recently observed by the IceCube collaboration [2], consideration of the...
The gauge symmetry of the Standard Model is SU(3)×SU(2)×U(1) on unknown reasons. One aspect that can be addressed is the low dimensionality of all its subgroups. Why not much larger groups like SU(7), or for that matter, SP(38) or E7?
We observe that fermions charged under large groups acquire much bigger dynamical masses, all things being equal at a high e.g. GUT scale, than ordinary quarks....
In the next decades several experiments will attempt to determine the neutrino mass hierarchy, i.e. the sign of $\Delta m_{31}$. Since the two hierarchies are non-nested hypotheses, $\Delta\chi^2=\chi^2_{IH}-\chi^2_{NH}$ does not follow a one-degree-of-freedom chi-square distribution (for example, it can be negative): it is possible to prove that, under certain assumption, it follows a...
In order for supersymmetry to stabilise the Higgs boson mass, the mass of the scalar partner of the top quark (the stop) is required to be below around 1 TeV. The decay of the stop depends on the mass difference between the stop itself and the lightes neutralino, assumed to be stable. Scenarios where this mass difference is small are usually referred to as “compressed”. This poster presents a...
Searches for exotic decay of the scalar Higgs boson to a pair of light pseudoscalar α bosons, which subsequently decay into pairs of muons and taus are performed using data collected by the CMS Experiment at centre-of-mass energies 8 and 13 TeV in addition to data based on future runs. This scenario is modivated by the 2HDM+S model which predicts the existence of supersymmetric higgs bosons....
Among the many challenges to be brought by the high luminosities of the HL-LHC is the impact of increased hit rates in the cathode strip chambers of the CMS endcap muon system. These chambers are used for all levels of trigger as well as offline reconstruction. Neutrons (both fast and thermal) induce background hits via nuclear interactions and capture, followed by gamma emission and (mainly)...
The RPC system at the CMS Detector is operating successfully from beginning of the data taking. The high instantaneous luminosity causes an extremely high flux of ionizing particles. The long period of operation (Run1 and Run2) in a huge radiation background conditions, gives the opportunity to study the operation capability of the RPCs and also to predict a data-driven extrapolation about the...
The most recent results from CMS on the study of the SM Higgs boson decaying into a tau pair will be presented. The search, which makes use of full 2016 dataset, is performed.
Measuring triboson final states at the Large Hadron Collider provides a test of the non-Abelian structure of the Standard Model of particle physics. This structure gives rise to self-interactions of the electroweak gauge bosons and the SM predicts the exact strength of these couplings of the gauge bosons. Any observed deviation from the SM expectations would imply the existence of physics...
We show latest results of SUSY fits from the MasterCode collaboration, and the status of the recast of ATLAS and CMS 13 TeV SUSY searches being incorporated in coming analyses.
Supersymmetry (SUSY) is one of the most studied theories to extend the Standard Model (SM) beyond the electroweak scale. If R-parity is conserved, SUSY particles are produced in pairs and the lightest supersymmetric particle (LSP), which is typically the lightest neutrino chi_0^1, is stable. In many models the LSP can be a suitable candidate for dark matter. This poster presents a search for...
LaBr3:Ce crystals and later CeBr3, PrLuAG and Ce:CAAG have been introduced for radiation imaging in medical physics, with photomultiplier or single SiPM readout (up to 3x3 mm2). An R&D was pursued with different types of crystals to realize compact large area detectors (up to some cm2) with SiPM array readout, aiming at high light yields, good energy resolution, good detector linearity and...
Particle physics is one of the most remarkable endeavours undertaken by mankind. However, the achievements are largely beyond reach for all but the particle physicists themselves. Popular science and high school text books being riddled with oversimplified and to some extent incorrect information, learning these topics becomes virtually impossible for anyone outside of the field.
In this talk...
CP violation in weak interactions is well-established in Particle Physics. Nevertheless, the most recent combination of all CP violation measurements is found to be insufficient to explain the size of the matter-antimatter asymmetry present in the Universe. The large number of top-antitop pair events produced in pp collisions at the Large Hadron Collider (LHC) provides a unique source of...
We investigate new gram-scale cryogenic detectors, 1-2 orders of magnitude smaller in size than previous devices. These are expected to reach unprecedentedly low energy thresholds, in the 10 eV-regime and below. This technology allows new approaches in rare-event searches, including the search for MeV-scale dark matter, detection of solar neutrinos and a rapid discovery of coherent...
The experiment of Krasznahorkay et al observed the transition of a 8Be excited state to its ground state and accompanied by an emission of e+e− pair with 17 MeV invariant mass. This 6.8σ anomaly can be fitted by a new light gauge boson. We consider the new particle as a U(1) gauge boson, Z′, which plays as a portal linking dark sector and visible sector. In particular, we study the new U(1)...
BM@N (Baryonic Matter at Nuclotron) is the first experiment to be realized at the accelerator complex of NICA-Nuclotron at JINR (Dubna, Russia). The aim of the experiment is to study interactions of relativistic heavy ion beams with energy up to 5.5 AGeV with fixed targets. The research program of the experiment includes studies of strange mesons, multi-strange hyperons and light hyper-nuclei...
The Compact Muon Solenoid (CMS) experiment implements a sophisticated two-level triggering system composed of the Level-1, instrumented by custom-design hardware boards, and a software High-Level-Trigger. A new Level-1 trigger architecture with improved performance is now being used to maintain the thresholds used in LHC Run I for the more challenging conditions experienced during Run II. We...
The CMS experiment implements a sophisticated two-level triggering system composed of Level-1, instrumented by custom-design hardware boards, and a software High-Level-Trigger. A new Level-1 trigger architecture with improved performance is now being used to maintain the thresholds that were used in LHC Run I for the more challenging luminosity conditions experienced during Run II. The...
The CMS experiment, located at the CERN Large Hadron Collider, has a redundant muon system composed by three different detector technologies: Cathode Strip Chambers (in the forward regions), Drift Tubes (in the central region), and Resistive Plate Chambers (both in the central and forward regions). The RPCs are designed mainly as a trigger detector but they contribute also to the muon...
The Cryogenic Underground Observatory for Rare Events (CUORE) is a ton-scale Neutrino-less Double Beta Decay experiment that uses 998 TeO2 crystal bolometers that need to be operated at a baseline temperature of around 10 mK. The large volume and masses involved require a dedicated precooling system that allows the apparatus to reach a threshold temperature after which the Dilution Unit, a...
The MEG experiment, at the PSI in Switzerland, aims at searching the charged lepton flavor violating decay $\mu^{+}\rightarrow e^{+}\gamma$. MEG has already determined the world best upper limit on the branching ratio: BR<4.2$\times10^{-13}$@90\%CL with the full data set collected in the years 2009-2013.\
The new positron tracker is a high transparency single volume, full stereo cylindrical...
DUNE, the DEEP Underground Neutrino Experiment, will be a groundbreaking experiment for long-baseline neutrino oscillation studies, and for neutrino astrophysics and nucleon decay searches. Planning of DUNE continues to proceed rapidly. The DUNE Far Detector will consist of four 10-kiloton fiducial volume modular liquid argon time-projection chambers (LArTPC) placed deep underground at the...
We investigate the influence of the fourth generation of quarks on the CP-asymmetry in $B_s \rightarrow \phi \ell^+\ell^-$ Decay.
This new quarks changes the values of the Wilson coefficients $C_7(\mu)$, $C_9(\mu)$ and $C_{10}(\mu)$ via virtual exchange of the fourth generation up type quark $t^\prime$.
Taking the $|V_{tb} V^*_{ts}| \sim$ $\{0.01-0.03\}$ with phase $\{60,90,120\}$
, which is...
Euclid is an ESA mission designed to explore the dark side of the Universe and to understand the nature of the dark energy responsible for the accelerated expansion of the Universe. Its objective is to map the geometry of the dark Universe by investigating the distance-redshift relationship and the evolution of cosmic structures.
By measuring two cosmological probes simultaneously, the Weak...
Since 1984 the INFN groups collaborating with Fermilab have been running a 2-month long summer training program for Italian university students. In 1984 the program involved only a few Pisa physics students, but it was later extended to engineering students. Since 2004 the program has been supported in part by DOE in the frame of an exchange agreement with INFN. In 2007 the Sant’Anna School...
The LHeC is the prime candidate for future electron-hadron (proton and ion) collisions at the energy frontier. This talk presents recent developments on its design as both a most precise QCD machine and a high-luminosity Higgs and BSM physics facility, including new results on beam-beam and interaction region studies, on the detector design and a brief overview of its physics program. The LHeC...
The latest results of the measurement of the Higgs boson decaying into two photons with the full 2016 data will be presented. The analysis is performed using the dataset recorded by the CMS experiment at the LHC from pp collisions at centre-of-mass energies of 13 TeV corresponding to an integrated luminosity of 35.9 1/fb.
We discuss how long strings can arise at the stretched horizon and how they can account for the Bekenstein-Hawking entropy. We use the thermal scalar field theory to derive the asymptotic density of states and corresponding stress tensor of a microcanonical long string gas in Rindler space.
We show that the equality of the Hagedorn and Hawking temperatures gives rise to the tree-level...
Producing the very large samples of simulated events required by many physics and performance studies with the ATLAS detector
using the full Geant4 detector simulation is highly CPU intensive. Fast simulation tools are a useful way of reducing CPU requirements when detailed detector simulations are not needed. During the LHC Run-1, a fast calorimeter simulation (FastCaloSim) was successfully...
Icarus is the largest imaging LAr TPC ever operated. During its LNGS run on the CNGS neutrino beam, from 2010 to 2013, produced some thousands neutrino events of unprecedented quality. This was possible thanks its mechanical precision and stability, liquid argon purity and electronics front-end and DAQ. In this poster the last issue (front-end and DAQ) will be presented in detail. Actually...
Using the analogy with the problem of ionization and
excitation of atoms at the propagation of relativistic charged particles through matter, the process of Coulomb dissociation
of weakly bound relativistic nuclei and hypernuclei is theoretically investigated in the framework of the two-cluster deuteron-like model. Explicit expressions for the total cross-section of Coulomb disintegration of...
The ability to identify jets with b-hadrons is essential for many physics analyses at the LHC. In ATLAS there are several algorithms available to tag jets induced by b-hadrons. These jets can be identified by the presence of secondary decay vertices, which are usually displaced from the primary vertex, due to the lifetime of b- and c-hadrons inside a jet. The secondary vertex finding algorithm...
b-tagging plays a fundamental role at LHC, as it helps in the identification of heavy particles that decay to bottom quarks, such as the top quark, Higgs boson or heavy exotic particles. The Soft Muon Tagger (SMT) allows jets from b-quarks to be identified, taking advantage of the presence of a muon coming from semileptonic decays of b-hadrons. The development of this new b-tagger in ATLAS...
In this contribution, we briefly analyze the formalism of the unquenched quark model (UQM) and its application to calculate the mass shifts of ground-state octet and decuplet baryons due to the coupling to the meson-baryon continuum. We describe the electro-production of Baryon-Meson states from proton in the framework of the UQM. Finally, we discuss the strangeness suppression factor within...
The advanced $\Lambda$, $\Sigma$, $\Xi$ hyperon Unitary and Analytic electromagnetic structure models are constructed explicitly and behaviours of $|G_M^H(t)|$ and ratios $|G_E^H(t)|/|G_M^H(t)|$ are predicted in time-like region as functions of the total energy squared $t=W^2$ in the c.m. system of $H\bar H$, which will be found out in intended
measurements of the $\Lambda$, $\Sigma$, $\Xi$...
One of the very interesting aspects in the high energy heavy-ion collisions experiments and in nuclear astrophysics is a detailed study of the thermody- namic properties of strongly interacting nuclear matter far away from the nu- clear ground state. The main goal of this contribution is to show that thermo- dynamic instabilities and phase transitions can take place at nite net baryon density...
The identification of jets originating from the hadronisation of heavy-flavour quarks represents a key ingredient in the physics program of the ATLAS experiment. Exploiting the topological structure of weak b- and c-hadron decays, the multi-vertex finder algorithm - JetFitter - tries to reconstruct the full b-hadron decay chain inside b-jets and provides a complementary approach to...
Quantum Mechanics is being included in numerous school programmes as part of the curriculum. Most modern textbooks introduce it emphasising its strange or at least uncommon, somewhat paradoxical character. We argue that such an approach is wrong because rather than attracting the interest of students toward the topic, it makes it almost unbelievable and artificial. The resulting...
In high-energy physics experiments, track based selection in the online environment is crucial for the detection of physics processes of interest for further study. This is of particular importance at the Large Hadron Collider (LHC), where the increasingly harsh collision environment is challenging participating experiments to improve the performance of their online selection. Principle among...
Lepton and photon triggers covering transverse energies from a few GeV to several TeV are essential for signal selection in a wide variety of ATLAS physics analyses studying Standard Model processes and searching for new phenomena. Final states including leptons and photons had, for example, an important role in the discovery and measurement of the Higgs boson. In ATLAS, dedicated triggers are...
Many extensions of the Standard Model (SM) include particles that are neutral, weakly coupled, and long-lived that can decay to final states containing several hadronic jets. Long-lived particles (LLPs) can be detected as displaced decays from the interaction point, or missing energy if they escape. ATLAS and CMS have performed searches at the LHC and significant exclusion limits have been set...
This paper explores effects of both finite width and interference (with background) in the production and decay of extra heavy quarks at the Large Hadron Collider (LHC). This dynamics is normally ignored in the standard experimental searcher and we assess herein the regions of validity of current approaches. Further, we discuss the configuration of masses, widths and couplings where the latter...
The production of jets in association with a W or a Z boson in proton-proton collisions is an important process to study QCD in multi-scale environments. Moreover, measurements of W/Z boson production associated with heavy- flavor (HF) quarks provide important experimental constraints to improve the theoretical description of these processes, as the uncertainties in the current predictions...
In absence of a direct discovery of new particles, precision measurements of the properties of known particles will provide the most powerful probe for phenomena beyond the Standard Model.
Future electron positron linear colliders with polarised beams, like the International Linear Collider (ILC), will provide a unique laboratory for such measurements, complementary to hadron colliders.
In...
