The Mu3e Experiment at PSI

Abstract

The Mu3e experiment will search for the lepton flavor violating neutrinoless muon decay μ+→e+e−e+ with a sensitivity down to 10−16 (90% C.L.) using the world most intense continuous muon beam at the Paul Scherrer Institute. This decay is strongly suppressed in the Standard Model (BR<10−56). Several Beyond the SM models predict observable effects accessible to the new generation of LFV experiments. The search for the μ+→e+e−e+ decay requires excellent momentum, spacial, and time resolution to suppress backgrounds, high rate capability (detect more than 109 stopped muons per second), and large acceptance. The required detector performance is possible thanks to tracking detectors based on thin monolithic active silicon pixel sensors with high granularity (HV-MAPS), which incorporate the complete read-out electronics on the sensor chip, and very precise timing measurements using scintillating fibers and tiles coupled to silicon photo-multipliers operating at very high particle rates.