0801 Group meeting Shiuan-Hal
Content 1. How to measure the muon lifetime? 2. The previous measurements. 3. The MuLan experiment. 4. What is muon capture? 5. The MuCap experiment.
How to measure the muon lifetime? The muon lifetime is :
How is the muon lifetime measured?
How is the muon lifetime measured?
How is the muon lifetime measured?
How is the muon lifetime measured?
How is the muon lifetime measured?
How is the muon lifetime measured?
How is the muon lifetime measured?
How long will it take? Source Muon rate Time to 1012 Cosmic rays 1 / 50 cm2 s 1 / hand s ~104 years e+ Scint. PMT p+ Continuous beam 20 kHz ~1.6 years beam time m+ PMT PMT Water e+ Pulsed beam (usable) ~ 3 weeks beam time
Why use m+ Muon capture
Previous Measurements of the Muon Lifetime Measured Lifetime Year PDG Average Bardin* 1984 Bardin Giovanetti* 1981 Balandin 1974 Duclos 1973 Williams and Williams 1972 Meyer 1963 Eckhause Lundy 1962 Farley The previous measurements
Experiment by G. Bardin 1 1. Incidence 140MeV/C beam 2. stopped in the sulphur target and provide an unplarized 3. The decay position was detected by scintillator(Sc) p+ p+ m+
Experiment by K. L. Giovanetti Start: S1 S2 Stop: L R 1. Incidence beam 2. stopped in the water 3. The decay position was detected by PMT L and R m+ m+
The MuLan Experiment BEAM m+ DETECTORS DIGITIZERS DAQ #4
The MuLan result
What is muon capture? μ nucleus Matter e μ
The previous measurements Trigger condition: Stopped muon:1 2 Gamma ray:3 X
The MuCap experiment e m
The MuCap experiment
ultra-pure hydrogen The muon will capture by P E m- e- p
The MuCap result The muon disappearance rate in pure hydrogen is: Because the lifetime is :