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New results from analyses of rare K+ and π decays at NA62
Get PDFThe CERN NA62 experiment is dedicated to rare kaon decays. Data collected during Run1 (2016-2017-2018) already constitute the largest sample ever of detected K+ decays and offer unprecedented opportunities to test the SM or to
search for New Physics in a variety of rare kaon and pion decays. The preliminary NA62 precision measurement of the π0 → e+e− decay branching fraction is reported in the following, together with the recently published study of the K+ → π+γγ decay and the first search for an axion-like particle (a) coupling to gluons in the decay chain K+ → π+a,a → γγ
Latest results in the τ physics and the dark sector from the Belle II experiment
Get PDFBelle II has a leading role in the τ sector and dark sector due to its large τ sample and unique sensitivity for a broad class of models postulating the existence of dark matter particles with masses in the MeV-GeV range. We present
recent world-leading results from the Belle II collaboration for: lepton universality test through the leptonic τ decay; search for a lepton flavor violating τ decay; production of an X state decaying in two muons, interpretable both as a Z′ boson or a muonphilic dark scalar; search for a long-lived scalar or axion-like particle produced in decays of B-mesons
Evolution of an effective Hubble constant in modified gravity
Get PDFWe investigate the Hubble constant tension within f(R) modified gravity in the Jordan frame, focusing on its application to the dynamics of an isotropic Universe. A scalar field, non-minimally coupled to the metric, provides an extra degree of freedom compared to General Relativity. We analyze the impact of such a scalar field on the cosmic expansion, leading to an effective Hubble constant Heff 0 (z), dependent on redshift z. We show that our f(R) model might mimic dark energy and provide an apparent variation of the Hubble constant. Our results align with recent cosmological data analysis in redshift bins, indicating a decreasing trend of the Hubble constant. The redshift dependence of Heff 0 (z) might potentially reconcile
measurements of the Hubble constant from probes at different redshifts
System test for the Barrel Pixel Detector for the CMS HL-LHC Upgrades
Get PDFThe CMS Experiment will be upgraded in order to cope with the High Luminosity Phase of LHC (HL-LHC). The inner tracker will be completely replaced with a new detector capable of operating in the foreseen high level of radiation during HL-LHC. In order to power the pixel detector, while decreasing the passive material and limiting the radiation damage, a new scheme, based on serial powering, will be deployed, with a read-out system designed to work at high data rates. In order to verify that the components behave as expected when combined together, system tests are performed. The latest updates on the system test of the barrel Pixel Detector, having a full-scale system bench will be discussed in terms
of threshold and noise. The latest results obtained with the optical read-out is also presented
Searching for light Dark Matter with NA64-e and POKER at CERN
Get PDFLight dark matter (LDM) is a theoretically well motivated model providing an attractive explanation for the observed relic dark matter density. In this scenario, LDM is composed of sub-GeV particles, feebly interacting with ordinary matter via a new force. NA64-e is a missing energy experiment at CERN Super Proton Synchrotron (SPS), aiming to produce LDM particles using the 100-GeV SPS electron beam impinging on a thick, active target (electromagnetic calorimeter). Each impinging electron is tagged and its momentum is measured; the LDM production signature consists in a large difference between the initial electron energy and the measured energy deposition in the calorimeter. In last years, NA64-e collected data also with a positron beam, in order to exploit the e+−e− resonant annihilation process for the Aproduction, synergistically with the POKER (POsitron resonant annihilation into darK mattER) project. POKER is an ERC-funded effort, whose aim is to perform a preliminary missing-energy measurement with a multi-energy positron beam. POKER will exploit the NA64−e experimental setup, using a new high-resolution PbWO4 electromagnetic calorimeter as an active target. This document presents the status of the NA64-e experiment, its latest results and
future prospects. Advances in the POKER program are reported, with a focus on the analysis of the latest positron data-takings performed during 2022 and 2023
Cosmology with gravitational waves: Inferring the Hubble constant with standard sirens
Get PDFThe following proceeding aims to provide an overview of the discussion presented at the 20th edition of “Incontri di Fisica delle Alte Energie” (IFAE) held in Florence from 3 to 5 April 2024. We will delve into some of the principal
cosmological inference methods currently available using gravitational waves detected by the LIGO, Virgo, and KAGRA interferometers. Our focus will be the Hubble constant estimation with standard sirens, thus called gravitational wave detections, which have the property to provide directly the source’s luminosity distance. The use of sirens for cosmological studies had been proposed long before the first gravitational wave detection by B. Schutz and has been further developed within the Bayesian framework by several authors. In particular, the following proceeding will
provide a brief description of the bright siren method, the spectral siren method, and how to measure the Hubble constant with the support of the galaxy catalogue information. These new statistical approaches show potential with the first published data, offering only a glimpse of the precision and accuracy achievable in the coming years with third-generation interferometers and increasingly accurate galaxy redshift measurements
Study of the galactic cosmic rays with the DAMPE space mission
Get PDFDAMPE (DArk Matter Particle Explorer) is a space-based
experiment, operative since December 2015. Its main scientific objectives include the indirect search for dark matter in the spectra of leptons and gamma rays, the study
of primary cosmic rays up to energies of hundreds of TeV, and gamma-ray astronomy. In this contribution the main results obtained so far in the study of the energy spectra of e− +e+, protons and nuclei are described
The LISA mission: A space-based gravitational-wave observatory
Get PDFIn January 2024, the European Space Agency (ESA) officially approved the Laser Interferometer Space Antenna (LISA) mission, which now moves into the implementation phase. With a planned launch in 2035, LISA is envisioned as the first space-based gravitational-wave observatory, sensitive at frequencies between 100 μHz and 1 Hz, not accessible to ground-based observatories. Given the size of the project and the stringent experimental requirements (measurement of
femto-g accelerations with picometer displacement sensitivity, between objects millions of kilometers away), LISA represents a complex challenge from many points of
view: technological, scientific, engineering, and organizational. Here we summarize the main features of the mission, with a focus on the contribution from Italy
Charm physics studies at CMS
Get PDFThe extraction of the charm cross section provides a test of Quantum Chromodynamics. At the CMS experiment, measurements are performed by studying the decay chain of the D∗ meson. Some common aspects of the studies performed are discussed, together with recent results concerning fragmentation
non-universality
Validation and Certification of the RPC-BI chambers for the ATLAS Muon Spectrometer Phase-II upgrade
Get PDFThe ATLAS experiment has started the construction of a layer
of Resistive Plate Chambers (RPC) to be installed during the long shutdown LS3 (2026-2029), above the MDT tracking chambers of the innermost layer of the barrel muon spectrometer. These new detectors will participate, along with the other RPC chambers already present in the spectrometer, in the very rapid selection (trigger) of
charged particles in small momentum intervals. The RPC chambers will consist of a triple layer of detectors that, at the luminosity of High Luminosity LHC, will have a detection efficiency of 80% per single layer (99.2% per chamber), a time resolution better than 400 ps, and a spatial resolution better than 6 mm in the η direction and 15 mm in the φ direction. The construction of the RPC detectors in the Large sectors (RPC-BIL), a joint effort by the INFN groups in Rome1, Rome2, Bologna and Cosenza, began in June 2023 and will continue until the start of LS3, scheduled for 2026. The assembly of the 130 RPC-BIL chambers will be carried out at the CERN laboratories. Each assembly phase is followed by quality tests. Specifically, the individual detectors of each chamber (singlets) are qualified into a cosmic ray tracking test station. The station allows for a complete measurement of detection
efficiency and the percentage of streamers as a function of the operating voltage. The trigger chambers of the station are the ATLAS RPC detectors. Therefore the test stand integrates both the existing ATLAS system and the Phase-II detectors; as such it serves as a validation system for the individual detectors and complete chambers and as a study system for the integration of the two technologies. This
work presents the first results and the potential of this test system