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CRILIN: A semi-homogeneous crystal calorimeter for the Muon Collider
Full text linkA muon collider is being proposed as a next generation facility. The incredible physics potential comes at the cost of technological challenges due to the short muon lifetime. From the detector side, the beam-induced background, pro-
duced by the muon decays in the beams and subsequent interactions, may potentially limit the physics performance. As an example, a diffused flux of photons and neutrons passes through the calorimeter system, which thus requires a design to avoid this substantial background. The Crilin calorimeter is being studied as a valuable option for the muon collider electromagnetic calorimeter: it is a semi-homogeneous calorimetric system with Lead Fluoride (PbF2) crystals interfaced with Silicon Pho-tomultipliers (SiPMs). In this talk the simulation studies towards the Crilin design are presented. The experimental tests on a prototype, consisting of two layers of 3 × 3 PbF2 crystals each, performed using 40–150 GeV electrons at CERN H2, are also presented. These tests are fundamental to demonstrate that the requirements established with the muon collider simulation are achieved by the Crilin technology
Direct measurement of charm baryons dipole moments at LHC
Full text linkThe magnetic and electric dipole moments of fundamental particles serve as valuable tools for studying physics within and beyond the Standard Model. However, experimental access to these short-lived particles has been challenging due to their brief lifetimes. A new experimental technique has been developed to directly measure the electromagnetic dipole moments of charm baryons, and potentially the tau lepton, at the Large Hadron Collider (LHC). The experimental test is planned for 2025 in the IR3 region of the LHC and aims to demonstrate the feasibility of a fixed-target experiment using bent crystals. This test will validate the proposed methodology and lay the groundwork for a future experiment on the dipole moments of charm baryons. Prospects for the future experiment and the expected sensitivity in various luminosity scenarios will be discussed
Targeted search for point sources of neutrons using data from the Pierre Auger Observatory
Full text linkSince the arrival directions of neutral particles point directly to their origin, they can be used to investigate sources of ultra-high-energy cosmic rays (UHECRs). The emission of UHECRs from a source is expected to be
accompanied by the production of neutrons in its vicinity in nuclear interactions and via photo-pion production. Free neutrons undergo β-decay and travel a mean distance of 9.2×(E/EeV) kpc. Therefore, neutron fluxes in the EeV range could be detected on Earth from sources of UHECRs in our Galaxy. Using cosmic ray data from the Surface Detector of the Pierre Auger Observatory, the largest cosmic ray detector in the world, we investigate neutron fluxes from Galactic candidate sources. Since we cannot distinguish between air showers initiated by protons and neutrons, a neutron flux could be identified as an excess of cosmic ray events around the direction of the candidate source. We look for excesses by comparing the observed signal with the
background contribution. As candidate sources, we select objects of astrophysical interest, such as pulsars, microquasars, and magnetars. We also consider the Galactic center and the Crab Nebula as targets, as well as a subset of the gamma-ray emitters detected by LHAASO. We consider cosmic ray events with declinations from −90◦ up to +45◦ and energies starting at 0.1 EeV. Although we do not find
evidence of a significant excess of events that could indicate a neutron flux from any of the tested targets, we establish the upper limit of the neutron flux in each
investigated case
Missing Energy decays of a B meson at Belle II
Full text linkWe present recent results of missing energy decays of B-mesons based on data collected at the Υ(4S) resonance by the Belle II experiment. This report includes two key analyses focusing on τ over μ/e lepton universality. The first is the
measurement of the branching-fraction ratio R(D∗ τ/ )=B(B → D∗τ−ντ)/B(B → D∗−ν )using hadronic tagging. The second is the first measurement of the inclusive ratio R(Xτ/)=B(B → Xτ−ντ)/B(B → X−ν ). We also present the branching fraction ratios R(Xe/μ)=B(B → Xe−νe)/B(B → Xμ−νμ). Finally, we present a simultaneous measurement of the magnitude of the CKM matrix |Vub| using the semileptonic b → u transitions: B0 → π−+ν and B− → ρ0+ν. All results are consistent with the corresponding Standard Model predictions
WLS System for the Pressurized Helium Calorimeter ``PHeSCAMI''
Full text linkThe possible presence of low-energy anti-deuterons in cosmic rays is a golden channel to test the antimatter asymmetry in the Universe or to identify annihilating Dark Matter particles in the galactic halo. The PHeSCAMI (Pressurized Helium Scintillating Calorimeter for AntiMatter Identification) project aims to study a new signature for the identification of anti-deuteron and anti-protons in
cosmic rays. In particular, when a Z=-1 heavy antiparticle is stopping in Helium, it can produce an exotic atom having lifetime of microseconds. Helium gas is a fast scintillator, thus a relatively simple calorimetric measurement of the stopping particle kinetic energy is possible. A two-stage Wavelength Shifter (WLS) system is necessary to convert the VUV (80 nm) scintillation light into visible. The perfor
mances of the FB118 WLS, manufactured by “Glass to Power”, are investigated. A promising usage of FB118 as a high-efficiency Cherenkov radiator is also inferred
Porte aperte al CNR: #patrimonioculturale nelle transizioni verde e digitale
Full text linkL’Edited Book raccoglie alcuni dei contributi di ricercatori e ricercatrici di vari istituti del CNR e università, liberi professionisti e stakeholder operanti nel settore del patrimonio culturale intervenuti all’evento “PORTE APERTE AL CNR: #patrimonioculturale nelle transizioni verde e digitale”, un festival di tre giorni ricco di eventi e incontri (Heriday, Genius Academy, Rainbow Encounters), tenutosi a Firenze alla Manifattura Tabacchi nei giorni dal 10 al 12 ottobre 2023, per riflettere e condividere esperienze di lavoro e strategie di ricerca scientifica e per celebrare tutti insieme i cento anni dalla fondazione del Consiglio Nazionale delle Ricerche
Searches for the Chiral Magnetic Effect in Xe--Xe and Pb--Pb collisions with ALICE
Full text linkMeasurements of charge-dependent three-particle correlations in Pb–Pb and Xe–Xe collisions at √ sNN = 5.02 TeV and 5.44 TeV, respectively, are presented. For Pb–Pb collisions, the event shape engineering technique has been employed in the analysis. Results on the centrality dependence of the three-particle correlator γαβ ≡⟨cos(ϕα +ϕβ −2Ψ2)⟩ (α,β denote the charge sign), used to search for the Chiral Magnetic Effect (CME), are reported in the transverse momentum interval 0.2 ≤ pT < 5.0GeV/c within the pseudorapidity range ∣η∣<0.8. The charge dependence of γαβ has similar magnitudes in the two collision systems pointing to large background contributions. It is quantitatively reproduced by the Anomalous Viscous Fluid Dynamics model and by a blast wave model calculation that includes non-CME effects in Xe–Xe collisions. Furthermore, these measurements combined with Monte Carlo Glauber and TRENTo simulations of the magnetic field are used to estimate the fraction of the CME contribution to γαβ in Xe–Xe and Pb–Pb collisions
Measurement of azimuthal anisotropy of f0(980) and D0 in heavy ion collisions at CMS
Full text linkWe present novel insights into the elusive f0(980) hadron’s quark composition and the interaction of heavy charm quarks with the quark-gluon plasma (QGP) through the anisotropic flow measurement of D0 in Heavy-Ion collisions. The f0(980), whose precise configuration has remained controversial, is reconstructed for the first time via its dominant decay channel, f0(980) → π+π−, using data from proton-lead collisions at 8.16 TeV, as collected by the CMS experiment. The azimuthal angle anisotropy v2 of f0(980) relative to the event plane is also investigated, allowing us to extract the v2 parameter for the f0(980) and compare it with other
hadrons. In addition, we also investigate how heavy quarks interact with QGP by measuring the coefficients of azimuthal anisotropy (vn)ofD0 mesons in lead-lead collisions at 5.02 TeV with CMS experiment. The measurements cover a wide range
of transverse momentum and thus reveal the flow formation mechanisms of heavy charm quarks, illuminating the diffusion and path-dependent parton energy loss
Searching for the X17 with the PADME experiment
Full text linkCertain classes of dark matter theories predict the existence of a new, hidden “Dark Sector” of particles which interact with Standard Model particles only through the exchange of a new, massive mediator. This is the scenario that the Positron Annihilation into Dark Matter Experiment (PADME) was originally designed to test using the positron beam at the Beam Test Facility (BTF) at the INFN Laboratori Nazionali di Frascati (LNF). The confirmation of the X17 anomaly in 2021, observed in internal pair creation nuclear decays at the ATOMKI institute in Debrecen, Hungary, kindled significant interest within the particle physics community. Assuming that the anomaly comes from the decay of a new particle to an e+e− pair, time-reversal symmetry implies that the new particle must be producible in e+e− annihilation. Since the beam used at PADME is the only one worldwide with the correct energy to create this new particle on resonance, the PADME collaboration pivoted to study the X17 anomaly in the reaction e+e− → X17 → e+e−,
aiming to confirm/disprove the particle hypothesis. In 2022, PADME Run III was dedicated specifically to this search. Approximately 1010 positrons on target were collected for each of the 47 beam energy values in the range 262 ÷ 298 MeV. This paper gives an overview of the scientific program of the experiment and of the data analyses ongoing
Kinetic and potential mechanisms for deuteron production in heavy-ion collisions within the PHQMD transport approach
Full text linkThis study explores the dynamical formation of deuterons in heavy ion collisions using the Parton-Hadron-Quantum-Molecular Dynamics (PHQMD) approach. Two production mechanisms are investigated: “kinetic” production via
“catalytic” reactions and “potential” interactions from nucleon attractive forces. Our analysis thoroughly examines all isospin channels for various reactions and considers deuteron finite-size properties. Results show that accounting for deuteron quantum properties significantly reduces the kinetic contribution in dense medium typical of heavy-ion collisions. Furthermore, by identifying potential deuterons with an advanced Minimum Spanning Tree (aMST) method, we obtain a satisfactory agreement with available experimental data