Mu2e Crystal Calorimeter Readout Electronics: Design and Characterisation

The Mu2e experiment at Fermi National Accelerator Laboratory will search for the charged-lepton flavour-violating neutrinoless conversion of negative muons into electrons in the Coulomb field of an Al nucleus. The conversion electron with a monoenergetic 104.967 MeV signature will be identified by a complementary measurement carried out by a high-resolution tracker and an electromagnetic calorimeter, improving by four orders of magnitude the current single-event sensitivity. The calorimeter—composed of 1348 pure CsI crystals arranged in two annular disks—has a high granularity, 10% energy resolution and 500 ps timing resolution for 100 MeV electrons. The readout, based on large-area UV-extended SiPMs, features a fully custom readout chain, from the analogue front-end electronics to the digitisation boards. The readout electronics design was validated for operation in vacuum and under magnetic fields. An extensive radiation hardness certification campaign certified the FEE design for doses up to 100 krad and 1012 n1MeVeq/cm2 and for single-event effects. A final vertical slice test on the final readout chain was carried out with cosmic rays on a large-scale calorimeter prototype

The Mu2e Crystal Calorimeter: An Overview

The Mu2e experiment at Fermilab will search for the standard model-forbidden, charged lepton flavour-violating conversion of a negative muon into an electron in the field of an aluminium nucleus. The distinctive signal signature is represented by a mono-energetic electron with an energy near the muon's rest mass. The experiment aims to improve the current single-event sensitivity by four orders of magnitude by means of a high-intensity pulsed muon beam and a high-precision tracking system. The electromagnetic calorimeter complements the tracker by providing high rejection power in muon to electron identification and a seed for track reconstruction while working in vacuum in presence of a 1 T axial magnetic field and in a harsh radiation environment. For 100 MeV electrons, the calorimeter should achieve: (a) a time resolution better than 0.5 ns, (b) an energy resolution <10%, and (c) a position resolution of 1 cm. The calorimeter design consists of two disks, each loaded with 674 undoped CsI crystals read out by two large-area arrays of UV-extended SiPMs and custom analogue and digital electronics. We describe here the status of construction for all calorimeter components and the performance measurements conducted on the large-sized prototype with electron beams and minimum ionizing particles at a cosmic ray test stand. A discussion of the calorimeter's engineering aspects and the on-going assembly is also reported

Latest results from KLOE-2

The KLOE experiment at the Frascati φ–factory recently obtained results on i) CPT and Lorentz invariance tests from the study of quantum interference of the neutral kaon pairs; ii) precision measurement of the branching fraction, BR(K+ → π+π−π+(γ) ) = 0.05565 ± 0.00031stat ± 0.00025syst, and iii) on dark photon searches with the analysis of the e+e− → µµγ final state. We have also studied the transition form factors of the φ meson to the pseudoscalars, π0 and η, that is presented in a separate contribution to this volume

DISCRETE 2010: Symposium on Prospects in the Physics of Discrete Symmetries

The Symposium on Prospects in the Physics of Discrete Symmetries is organized by the Physics Department of "Sapienza" University of Rome, and by INFN (Istituto Nazionale di Fisica Nucleare). This second edition of the Symposium, which was successfully held for the first time in Valencia in 2008, covers all theoretical and experimental progress in the field, and aims at a thorough discussion on the latest developments. The Symposium is organized in plenary sessions with invited talks, and parallel sessions with selected contributions from the submitted abstracts. The topics covered include T, C, P, CP symmetries; CPT symmetry, decoherence, Lorentz symmetry breaking; accidental symmetries (B, L conservation); neutrino mass and mixing; cosmology and astroparticles, dark matter searches; experimental prospects at LHC, Super flavor factories, and new facilities