Giovanni Onorato Fermilab University of Rome Guglielmo Marconi INFN Lecce Mu2e general presentation / 156 / 28 / Particle physics frontiers - Neutrino experiments (NOvA, LBNE, MINOS, MINERvA, and others ) - Precision measurements (g-2) - Rare decays (Mu2e) Mu2e collaboration / 156 / 28 / The lepton flavor violation Neutrinos have mass, so in the SM we can have Rate < (unmeasurably low) In new physics models one can have or in presence of a nucleus Experiments:Mu2e, SINDRUM II, TRIUMF, COMMET, and others Rate ~ / 156 / 28 / Present measurements / 156 / 28 / Mu2e achievements / 156 / 28 / Experimental setup 1 Proton beam hits production target in Production Solenoid. Pions captured and accelerated towards Transport Solenoid by graded field. Pions decay to muons. / 156 / 28 / Experimental setup II Transport solenoid performs sign and momentum selection. Eliminates high energy negative particles, positive particles and line-of- sight neutrals. Muons captured in stopping target. Conversion electron trajectory measured in tracker, validated in calorimeter. Cosmic Ray Veto surrounds Detector Solenoid. / 156 / 28 / Dominant background / 156 / 28 / Other background sources - Radiative muon/pion capture - Photon produced that can convert asymmetrically - Beam electrons can scatter in target - Muon/pion decay in flight - Antiprotons and other late arriving particles - Cosmic-ray induced electrons - Protons - Neutrons - Photons from Nuclear capture None of them produce a sharp peak at 105 MeV: they need to be well known and controlled. Work is going on on this / 156 / 28 / Detectors: the T-Tracker 18 stations + Stiffening rings at ends 12 panels, at 30 rotations, form a station 30 stereo angles give 400m resolution along wire Straw termination and readout at r>70cm / 156 / 28 / T-Tracker: straws structure 5mm straws Gaps between straws Double layer / 156 / 28 / Alt. ITracker (from INFN Lecce) / 156 / 28 / The calorimeter (from INFN Frascati/Pisa) / 156 / 28 / Location / 156 / 28 / Time schedule