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Rare and very rare decays of hadrons at LHCb
Get PDFThis contribution presents the most recent results related to rare
and very rare decays involving hadrons at the LHCb experiment. These results
encompass the decays Aob —> D-sp and # ++ cc —> #^+c T+ , using data obtained from proton-proton collisions at a center-of-mass energy of 13 TeV during the LHC Run 2 data-taking, corresponding to a total integrated luminosity of ~ 6 fb-1 . Additionally, this contribution includes the differential branching fraction measurement of the Aob —> A (1520) u+u- decay and updates on the searches for the Do —> u+u- and KoS (L) —> u+u-u+u- decays
Electromagnetic dipole moments of baryons with strangeness and charm at the LHC
Get PDFThe program for measuring electric and magnetic dipole moments can be extended to baryons with strangeness and charm at the LHC. The obser- vation of an electric dipole moment would provide a signal for physics beyond the Standard Model and the existence of a new mechanism for CP violation that could help explain the observed difference between matter and antimatter in the Universe. Measuring magnetic dipole moments is useful for validating non-perturbative quan- tum chromodynamics theoretical models and providing new information about the internal structure of hadrons. Additionally, measuring the magnetic dipole moment for a particle and its antiparticle would allow a test of the CPT symmetry. We present new possibilities for conducting such measurements at the LHC by exploit- ing the spin precession of baryons with charm in bent crystals and baryons with strangeness inside the magnet of the LHCb tracking system. Feasibility studies of the proposed techniques and the expected precision of the measurements will be outlined
The CNR activities for NBFC Spoke 7 “Biodiversity and society: communication, education and social impact”
Get PDFPromoting a more responsible behaviour and enhancing a more sustainable management of biodiversity
Road for LHC Run III: The ATLAS New Small Wheel and the MicroMegas chambers performances
Get PDFThe two New Small Wheels (NSWs) for the upgrade of the Atlas Muon Spectrometer are now installed in the experiment and ready to collect data in LHC Run III, which started in July 2022. The NSWs are the largest phase- 1 upgrade project of ATLAS. Its challenging completion and readiness for data taking is a remarkable achievement of the Collaboration. The two wheels (10 meters in diameter) have replaced the first muon stations in the high-rapidity regions of ATLAS and are equipped with multiple layers of two new detector technologies: the small-strip Thin Gap Chambers (sTGC) and the MicroMegas (MM). The latter are used in such a large scale in HEP experiments for the first time. Each detector technology will cover more than 1200 m2 of active area. The new system is designed to assure high tracking efficiency with a precision measurement of muon tracks together with a reduction of fake trigger rates in view of the higher background environment of the Hi-Lumi LHC programme. In this presentation, the motivation of the NSWs upgrade and the steps from the commissioning to the data taking together with the first results using the Run III data will be presented, focusing on the MicroMegas performances
Status of the production of GEM chambers for the CMS experiment at Large Hadron Collider
Get PDFThe High Luminosity LHC phase includes an upgrade to the muon stations for the CMS Experiment. CMS trigger and muon identification performance will be crucial, and it is, therefore, necessary to install new GEM stations to extend acceptance in the high-η region. An explanation of the quality control test and an update on the status of production will be provided
40 MHz Scouting for the CMS Level-1 Trigger
Get PDFThe Level-1 trigger Data Scouting (L1DS) is a novel data acquisition system under development for the Phase-2 CMS detector at the High-Luminosity LHC (HL-LHC). Its purpose is to capture and process Level-1 trigger (L1T) information at the bunch crossing collision frequency of the LHC preceding the standard L1T selections. Referred to as 40 MHz Scouting, this system has the potential for filterless diagnostics for the detector, luminosity studies and investigations into
signatures and processes that would be otherwise inaccessible or constrained due to the bias introduced by the trigger. An outline of Phase-2 L1DS is provided alongside a description of the Run-3 demonstrator’s architecture and the preliminary results obtained
First t-channel single top measurement in pp collisions at an energy in the centre-of-mass of s√=5.02 TeV with the ATLAS experiment
Get PDFA single top quark production measurement in proton-proton (pp) collisions at the Large Hadron Collider (LHC) at an energy in the centre-of-mass √s =5.02 TeV with data collected by the ATLAS experiment is reported. This
analysis uses a Boosted Decision Tree (BDT) to separate signal from background events and its output distribution is used for a Profile-Likelihood fit. Some of the calibrations used in this analysis are taken from a recent ATLAS top quark pair production cross-section measurement at the same energy of √s =5.02 TeV (ATLAS Collaboration, JHEP, 06 (2023) 138). The analysis takes into account forward jets to enhance the t-channel process, with an ad-hoc calibration for their energy
A new muon tomographer for glaciers melting monitoring
Get PDFThe project aims to develop a portable and easily replicable detector system that utilizes muon tomography to monitor and study glaciers. Muon tomography is a proven technique for studying large objects, and it take advantage in the on the natural flux of muons reaching the Earth’s surface. Since the density of rock and ice differs, the detector can provide insights into ice thickness and the ice rock interface, through the measurement of the directional muon flux. The detector design consists of five modules, each composed of two layers of scintillating fibers arranged orthogonally to determine the three-dimensional coordinates of muon hits. Silicon Photomultipliers (SiPMs) are used for signal acquisition and the read-out system was developed and tested in collaboration with CAEN S.p.A. Simulation results include assessments of angular resolution, reconstruction uniformity, and the stopping power of ice and rock. These simulations are essential for optimizing detector performance. Additionally, preliminary tests on the read-out boards and fully simulations involving real mountain profiles have been conducted. This project has the potential to significantly enhance our understanding of glacier behavior in the context of global warming
Understanding the nature of baryon resonances
Get PDFThis paper opens with a brief review of lattice QCD calculations showing the 2s radial excitation of the nucleon sits at approximately 2 GeV, well above the Roper resonance position. We then proceed to reconcile this observation
with experimental scattering data. While the idea of dressing quark-model states in a coupled-channel analysis to describe scattering data has been around for decades, it is now possible to bring these descriptions to the finite volume of lattice QCD for confrontation with lattice-QCD calculations. This combination of lattice QCD and
experiment demands that we reconsider our preconceived notions about the quark model and its excitation spectrum. We close with a discussion of an unanticipated resolution to the missing baryon resonances problem
Measuring neutron polarisation in pn production using CLAS
Get PDFUtilising a novel method, an independent measurement of neutron polarisation in deuteron photo-disintegration is determined with CLAS data from Jefferson Lab Hall B, covering previously inaccessible kinetic regimes, including the resonance energy region of the d∗(2380). After isolating the reaction of interest, a maximum likelihood technique and bootstrapping technique were used to determine the neutron polarisation transfer Cx and reliable extraction of associated uncertainties, substantially extending the kinematic coverage from previous measurements, most notably to higher energies. The demonstrated success of this technique paves the way for further analyses that can be brought to CLAS12 for other reactions with a neutron in the final state