K. Schmidt()(), X. Cao()(), E. J. Kim()(), K. Hagel(), M. Barbui(), J. Gauthier(), S. Wuenschel(), G. Giuliani()(), M. R. D. Rodrigues(), H. Zheng()(), M. Huang()(), N. Blando(), A. Bonasera()(), R. Wada(), C. Botosso(), G. Liu(), G. Viesti(), S. Moretto(), G. Prete(), S. Pesente(), D. Fabris(), Y. El Masri(), T. Keutgen(), S. Kowalski(), A. Kumar(), G. Zhang()() and J. B. Natowitz() () Institute of Physics, University of Silesia 40-007 Katowice, Poland () Cyclotron Institute, Texas A&M University College Station, TX 77843, USA () Shanghai Institute of Applied Physics, Chinese Academy of Sciences Shanghai 201800, China () Division of Science Education, Chonbuk National University Jeonju 561-756, Korea () INFN, Laboratori Nazionali del Sud via Santa Sofia, 62, 95123 Catania, Italy () Instituto de F́ısica, Universidade de São Paulo Caixa Postal 66318, CEP 05389-970, São Paulo, SP, Brazil () School of Physics and Information Technology, Shaanxi Normal University Xian 710119, China () College of Physics and Electronics information, Inner Mongolia University for Nationalities Tongliao, 028000, China () Dipartimento di Fisica dell’Università di Padova and INFN Sezione di Padova I-35131 Padova, Italy () INFN, Laboratori Nazionali di Legnaro I-35020 Legnaro (PD), Italy () Universite Catholique de Louvain B-1348 Louvain-la-Neuve, Belgium () Nuclear Physics Laboratory, Department of Physics, Banaras Hindu University 221005 Varanasi, India
Astronomical and cosmological observations indicate that a large amount of the energy content of the Universe is made of dark matter. The most promising dark matter candidates are the so-called WIMPs (Weakly Interacting Massive Particles). The XENON project, at the Gran Sasso National Laboratory (LNGS), consists of a double-phase time projection chamber (TPCs) using ultra-pure liquid Xenon as both target and detection medium for dark matter particle interactions. The WIMPs can be indeed detected via their elastic scattering off Xenon nuclei. The XENON Collaboration is now running the XENON1T experiment, the first ton scale liquid Xenon based TPC, with an active mass inside the TPC of about 2 t. Data were collected in a live time of 279 days of dark matter search up to February 2018. The detector presents the lowest electronic recoil background ever obtained in a dark matter experiment: (82(-3)(+5)(sys) +/- 3(stat)) events/(t x yr x keV(ee)). The results allowed to set the most stringent exclusion limits on the spin-independent WIMP-nucleon interaction cross section for WIMP masses above 6 GeV/c(2), with a minimum of 4.1 x 10(-47) cm(2) for 30 GeV/c(2) WIMP mass at 90% confidence level.
The experimental activity with the CHIMERA 4 pi detector in the last two years is reviewed in the light of the most recent technical achievements of the device. In fact the CHIMERA detector capabilities are going to be extended with the implementation of a new digital front-end electronics and the coupling with the FARCOS ancillary correlator array. The device has reached a sufficient versatility in order to obtain results for different and specific data analysis with stable and radioactive heavy ion beams, e.g., pygmy resonances, nuclear reactions of astrophysical interest, nuclear dynamics and study of the nuclear matter through the isospin degree of freedom. The obtained results and the expected future performances will be briefly discussed.
Since 2009, the BESIII experiment collected data in the center-of-energy range from 2 to 4.6 GeV, thus making it a unique environment to cover a broad range of physics topics. In this paper a selection of the recent BESIII results on the still mysterious XY Z states, hadron spectroscopy, as well as a very brief review on the charm and Lambda(c) physics are reported.
In the Next-to-Minimal-Supersymmetric-Standard-Model (NMSSM) the lightest supersymmetric particle (LSP) is a candidate for the dark matter (DM) in the universe. It is a mixture from the various gauginos and Higgsinos and can be bino-, Higgsino- or singlino-dominated. Singlino-dominated LSPs can have very low cross sections below the neutrino background from coherent neutrino scattering which is limiting the sensitivity of future direct DM search experiments. However, previous studies suggested that the combination of both, the spin-dependent (SD) and spin-independent (SI) searches are sensitive in complementary regions of parameter space, so considering both searches will allow to explore practically the whole parameter space of the NMSSM. In this letter, the different scenarios are investigated with a new scanning technique, which reveals that significant regions of the NMSSM parameter space cannot be explored, even if one considers both, SI and SD, searches.
Massive photon-like particles are predicted in many extensions of the Standard Model with a hidden sector accounting for dark matter candidates. They have interactions similar to the photon, are vector bosons, and can be produced together with photons. Most of the present experimental constraints on the dark photon (A) rely on the hypothesis of dominant decays to lepton pairs. The PADME experiment aims at searching for the e(+) e(-) -> gamma A process in a positron-on-target experiment, assuming a decay of the A into invisible particles of the hidden sector. The positron beam of the DA Phi NE Beam-Test Facility (BTF), produced by the LINAC at the Laboratori Nazionali di Frascati of INFN, will be used. The core of the experimental apparatus is a fine-grained, high-resolution calorimeter. It will measure with high precision the momentum of the photon in events with no other activity in the detector, thus allowing to measure the A mass as the missing mass in the final state. In about one year data taking, a sensitivity on the interaction strength (epsilon(2) parameter) down to 10(-6) is achievable, in the mass region from 1MeV < M-A < 23.7 MeV, running with 6000 positrons in 40 ns long bunches at 550MeV beam energy. The experiment, now in the construction phase, is planned to run in 2018. The status of the PADME detector and the physics potential of PADME is reviewed.
We examine the sensitivity of the particle spectrum to the parameters of the U(1)'-extended MSSM with R-parity violation. This model provides a simultaneous solution to both the mu-problem and the proton decay problem which plague the MSSM. We focus on variations of neutralino, chargino and Higgs boson masses in various lepton number violations couplings, scanning over all the space to find allowed regions of the parameter space consistent with the experimental constraints for these masses.
High-precision measurements by the ATLAS Collaboration are presented using data that were collected in proton-proton collisions at the LHC at several centre-of-mass energies. W+, W- and Z/gamma* production cross-sections are measured at root s = 7 and 13TeV. Ratios of top-quark pair to Z-boson cross-sections measured from proton-proton collisions at the LHC centre-of-mass energies of root s = 13, 8 and 7TeV are also presented. Finally, a measurement of the mass of the W-boson is also presented based on the 7TeV dataset with an integrated luminosity of 4.6 fb(-1).
This paper presents a search for a new $Z^\prime$ resonance decaying into a pair of dark quarks which hadronise into dark hadrons before promptly decaying back as Standard Model particles. This analysis is based on proton-proton collision data recorded at $\sqrt{s}=13$ TeV with the ATLAS detector at the Large Hadron Collider between 2015 and 2018, corresponding to an integrated luminosity of 139 fb$^{-1}$. After selecting events containing large-radius jets with high track multiplicity, the invariant mass distribution of the two highest-transverse-momentum jets is scanned to look for an excess above a data-driven estimate of the Standard Model multijet background. No significant excess of events is observed and the results are thus used to set 95 % confidence-level upper limits on the production cross-section times branching ratio of the $Z^\prime$ to dark quarks as a function of the $Z^\prime$ mass for various dark-quark scenarios.
We report the first dark matter search results from XENON1T, a ∼2000-kg-target-mass dual-phase (liquid-gas) xenon time projection chamber in operation at the Laboratori Nazionali del Gran Sasso in Italy and the first ton-scale detector of this kind. The blinded search used 34.2 live days of data acquired between November 2016 and January 2017. Inside the (1042±12)-kg fiducial mass and in the [5,40] keV_{nr} energy range of interest for weakly interacting massive particle (WIMP) dark matter searches, the electronic recoil background was (1.93±0.25)×10^{-4} events/(kg×day×keV_{ee}), the lowest ever achieved in such a dark matter detector. A profile likelihood analysis shows that the data are consistent with the background-only hypothesis. We derive the most stringent exclusion limits on the spin-independent WIMP-nucleon interaction cross section for WIMP masses above 10 GeV/c^{2}, with a minimum of 7.7×10^{-47} cm^{2} for 35-GeV/c^{2} WIMPs at 90% C.L.
Strongly interacting matter at very high temperature and density is expected to exist in a state called the Quark-Gluon Plasma (QGP), in which quark and gluon degrees of freedoni are liberated, and with properties very different from the hadronic matter we ordinarily find around us. The only means to study this fundamental state of matter is via the collisions of heavy nuclei in the laboratory. In this work an overview of the most important results on heavy-ion collisions phenomenology and on the study of the QGP properties is presented. Particular emphasis is given to the most recent results obtained at the LHC at CERN at the. highest collisions energy reached so far, with a look to the future scenarios.
— The search for electromagnetic counterparts or neutrino emissions from gravitational-wave sources engages a wide scientific community with a growing trend of collaborations. Here, we outline the pathway that led to the birth of multimessenger astronomy with the first direct observations of the three gravitationalwave signals measured to date, focusing on the new challenges to face in the near future.
Thick-GEMs (THGEMs) are simple and robust gaseous multipliers, derived from the GEM design and proposed for large-scale applications. Classical THGEMs consist of Printed Circuit Boards (PCBs) with a regular pattern of holes obtained by drilling; they are manufactured by industry in large series and large size: their response for different geometrical parameters acid operational conditions has been extensively studied. Different substrates (ceramic, glass, PTFE, etc.) and various production procedures have also been investigated with promising results. Different design options, like highly segmented electrodes, and different architectures, in particular those based on the Thick-WELL design are being actively studied. THGEMs are used as gaseous multipliers and as reflective photocathodes for VUV photons when coated with a CsI layer. THGEM-based Photon Detectors have been successfully implemented in 2016 on COMPASS RICH-1 for a total active area of 1.4m(2). Applications of THGEM (also called LENT) technology in the field of cryogenic detectors, ill particular for double-phase large volume Ar ones are proposed. The recently discovered phenomenon of bubble assisted electro-luminescence in liquid Xe opens the way to local dual phase cryogenic detector configurations when using THGEMs. The detection of X-rays and neutrons using THGEM-based devices is a very active field. Promising results have been obtained using THGEMs for imaging applications.
Although no experimental evidence has been found during LHC Run1, Supersymmetry (SUSY) remains one of the most promising and motivated Standard Model (SM) extensions. Focusing the attention on models where the multiplicative quantum number R-parity is conserved, the latest results in searching for pair production of top squarks decaying to a bottom quark and the lightest chargino or to a top quark and the lightest supersymmetric particle (neutralino) in final states with 2 leptons are presented, using proton-proton collision data collected by the ATLAS experiment during 2015 and 2016 at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 36.1 fb$^{-1}$. Each of the decay modes is searched in the context of a simplified model, assuming a branching ratio of 100% for both signal.
This contribution describes the first results obtained within the iMPACT project, which aims to build a novel proton computed tomography (pCT) scanner for protons of energy up to 230 MeV, as used in hadron therapy. We will first describe the design of the iMPACT scanner, which is composed by a tracker and a range calorimeter. Results of test-beams, focused on the characterization of the building elements of the prototype of the calorimeter, will be presented and compared with simulations.
In this study the results of tests performed at the T10 beam line at CERN on three novel MRPC detectors are reported. The tested detectors have different designs suited for different R&D goals: one detector has been built to improve the already excellent time resolution of the MRPC technology; the other two detectors have been designed and constructed to improve the MPRC rate capabilities. All the detectors are built maintaining the basic features of MRPCs: low price and ease of construction. The solutions adopted and described in this work for the time resolution improvement lead to a detection efficiency close to 100%, demonstrating the chamber functionality. To increase the MRPCs rate capabilities, a painted layer has been added to the surfaces of the MRPCs inner glass sheets. The measurements and tests performed showed that this solution can indeed increase the rate capability of the detector with respect to standard MRPC.
The H -> tau tau decay is an important decay mode of the Higgs boson as it allows to measure directly the Higgs coupling to fermions. This paper presents the measurement of the H -> tau tau cross-section and a test of CP invariance in the Higgs boson production performed in the same channel. The results achieved using the data collected by the ATLAS experiment during the Run 1 of the LHC (2011-2012), corresponding, to 20 fb(-1), are shown and future perspectives for the Run 2 are described as well.
The understanding of CP-violating mechanisms in the baryon sector is of particular importance in light of the observed matter-antimatter asymmetry in the Universe, but few studies have been performed in baryon decays to date. The searches for CP violation in beauty baryons performed by the LI1C1) Collaboration on LIIC Run I data are reported, including the first evidence for CP violation in a baryon decay, 7T. Prospects for TITC Run TT are also outlined.
The inclusive production of the charmonium state.(2S) was studied at root sNN = 8.16TeV in proton-lead collisions, using the ALICE detector at the CERN LHC. The measurement is performed in the two centre of mass rapidity ranges, 2.03 < y(cms) < 3.53 and -4.46 < y(cms) < -2.96, by reconstructing the.(2S) decay to a muon pair. The results are compared to those obtained for the J/psi at the same centre of mass energy by showing the ratios between the J/psi and.(2S) production cross sections and by studying the nuclear modification factor (RpA) as a function of transverse momentum (pT < 12 GeV/c) and rapidity. The comparison with.(2S) results in proton-lead collisions at root sNN = 5.02TeV and theoretical predictions is also shown.
