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Performance of the ToF detectors in the FOOT experiment
No full textThe FOOT (FragmentatiOn Of Target) experiment aims to determine the fragmentation cross-sections of nuclei of interest for particle therapy and radioprotection in space. The apparatus is composed of several detectors that allow fragment identification in terms of charge, mass, energy and direction. The fragment time of flight (ToF) along a lever arm of ∼2 m is used for particle ID, requiring a resolution below 100 ps to achieve a sufficient resolution in the fragment atomic mass identification. The timing performance of the ToF system evaluated with 12C and 16O beams is reviewed in this contribution
Single top quark measurements with the CMS experiment
No full textSingle top quarks are produced at the Large Hadron Collider in electroweak processes via charged current interaction. This channel is very sensible to new physics signals, like anomalous couplings or flavour changing neutral current, due to the presence of an electroweak vertex. The latest results obtained with the data collected by the CMS experiment (CMS Collaboration, JINST, 3 (2008) S08004) in 2015–2018 at √s = 13 TeV at the Large Hadron Collider, studying both inclusive and differential cross sections, allow to precisely probe the structure of the interaction vertex and to search for deviations from the Standard Model predictions
ATLAS searches for resonances decaying to boson pairs
No full textSearches for heavy-mass resonances decaying into a couple of vectorial bosons, WW, W Z or ZZ using data from proton-proton collisions at a centreof-mass energy of √s = 13 TeV at the Large Hadron Collider are presented. The searches are performed in the semileptonic and fully hadronic final states, in which one boson decays into leptons and the other one decays into hadrons, or both bosons decay hadronically. Semileptonic results refer to an integrated luminosity of 36.1 fb−1 recorded with the ATLAS detector in 2015–2016 while the fully hadronic results correspond to the full Run-II statistics, 139 fb−1. These results are
interpreted within the context of Standard Model extensions with additional Higgs bosons, a heavy vector triplet or warped extra dimensions
Observation of H → bb in ATLAS
No full textThe measurements of the Higgs boson decays to fermions allow to test the Yukawa couplings and to understand the mass generation of fermions. In the Standard Model, the H → b¯b decay is the dominating decay with a branching ratio
of 58%, although its observation is experimentally challenging at LHC because of the large multijet background. The search for the H → b¯b decay is therefore performed exploiting the associated production of a Higgs boson with a W or a Z boson (V = W/Z), whose leptonic decays make the signature of these processes easier to identify. This paper describes the search for the V H(→ b¯b) process using pp collisions data taken by ATLAS at LHC at 13 TeV and presents the first observation of the Higgs coupling to b-quarks. Differential cross section of the V H(→ b¯b) production at 13 TeV are also presented
General correlations to b → sμ+μ− anomalies from a rank condition
No full textIt is assumed that the New Physics addressing neutral-current
B-meson anomalies couples to a single direction in quark flavor space, i.e., that the Wilson coefficient matrix of the relevant semi-leptonic operators be of rank one. By correlating the observed anomalies to other flavor and high-pT observables, we constrain the possible flavor directions involved in our assumption
The hadronic vacuum polarization contribution to (gμ − 2): Lattice QCD+QED calculations
No full textThe anomalous magnetic moment of the muon aμ is one of the most accurate quantities in Particle Physics. The long-standing discrepancy of about 3.7 standard deviations between the experimental value and the prediction of the
Standard Model could represent an intriguing indication of New Physics. The experiments at Fermilab (E989) and at J-PARC (E34) aim at reducing significantly the experimental uncertainty, thus making the theoretical one due to hadronic corrections the main limitation of this stringent test of the Standard Model. In this contribution we present the results of a first-principle lattice calculation of the hadronic vacuum polarization (HVP) contribution to aμ, including electromagnetic and SU(2)-breaking corrections. Our determination, aHVP μ = 682.0 ∼ (18.7) · 10−10, turns out to be in agreement with recent theoretical determinations based on the dispersive analyses of the experimental cross section data for the annihilation process e+e− → hadrons. Furthermore, we provide for the first time a lattice estimate for the missing part of aHVP μ not covered in the MUonE experiment, [aHVP μ ]> = 91.6 ∼ (2.0) · 10−10
Search for the τ → μμμ decay at CMS
No full textThe results of a search for the τ → 3μ charged-lepton flavour violating decay in the CMS experiment are presented. The analysis is carried out on data collected during 2016 on proton-proton collisions at the centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 33 fb−1. The analysis selects τ leptons produced in B and D meson decays. No evidence of signal is observed and an upper limit of 8.8×10−8 is set on the τ → 3μ branching ratio at 90% of confidence level
Study of the production of a low emittance muon beam for the LEMMA project
No full textThe Low EMittance Muon Accelerator (LEMMA) is a concept for a positron-driven muon source for a future multi-TeV muon collider, which aims to produce a low emittance muon beam via positron-electron annihilation overcoming the need to cool the beam. I will describe the principles of this concept together with the first results of the muon production studies. I will also discuss the 6D emittance evolution through the production line for the single-target configuration. These studies have been performed with a novel simulation code developed for this purpose
Features and perspectives of the JUNO experiment
No full textWe discuss the characteristics and perspectives of JUNO, a huge reactor antineutrino experiment, with a very high energy resolution, designed to perform measurements relevant for particle physics and astrophysics. Its main goal is the determination (at 3–4 σ of confidence level) of neutrino mass ordering. JUNO should also significantly reduce the uncertainty on different mass and mixing parameters; it will have an high sensitivity to supernova neutrinos and it will study geoneutrinos and probably atmospheric neutrinos. The JUNO detection of 8B and 7Be solar neutrinos will contribute to the solar metallicity study and to test the LMA oscillation pattern, looking for signals of potential Non-Standard Interactions
Development of a particle tracker for space applications
No full textAstroparticle physics is often concerned with the observation of phenomena normally shielded by the Earth’s atmosphere or taking place in the exosphere, and so demands lightweight detectors suitable for space missions hosted on satellites. In this context particle tracking is concerned with the direct measurement of the trajectory of charged particles. Currently microstrip detectors are the typical technology used in space missions, but pixel detectors, with their higher resolution and a lower material budget, represent an interesting alternative. This paper gives a brief overview of a possible design of a 3-layers particle tracker based on the ALPIDE MAPS chip. With a total of around 100 chips and the stringent constraints imposed by a space mission, the deployment and readout of such detector requires careful optimizations to limit the power consumption but at the same time maintain useful performances. Such task is approached with a custom parallel readout architecture implemented on Field Programmable Gate Arrays (FPGA), with the aim of using
a single low-power FPGA chip for the entire detector