1. Mu2e general presentation

2. Particle physics frontiers • Neutrino experiments (NOvA, LBNE, MINOS, MINERvA, and others… ) • Precision measurements (g-2) • Rare decays (Mu2e) Mu2e collaboration

3. The lepton flavor violation Neutrinos have mass, so in the SM we can have Rate < 10-54 (unmeasurably low) In new physics models one can have Rate ~ 10-15 or in presence of a nucleus… Experiments:Mu2e, SINDRUM II, TRIUMF, COMMET, and others…

4. Present measurements

5. Mu2e achievements

6. 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.

7. 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.

8. Dominant background

9. 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

10. 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

11. T-Tracker: straws structure 5mm straws Gaps between straws Double layer

12. Alt. ITracker (from INFN Lecce)

13. The calorimeter (from INFN Frascati/Pisa)

14. Location

15. Time schedule