The muons are already old when they arrive at the detector s

The muons are already \"old\" when they arrive at the detector, so we never measure the actual lifetime o f any individual muon. Yet we claim to be measuring the lifetime of the muons. How can this be right? (Note: it has absolutely nothing to do with relativity and time dilation.)

Solution

life time of muon is 2.19micro sec. they produced in upper atomsphere by decay of cosmic ray pions. if they were completely stopped by scintillator they decay into electron and positron, nueutrios. a short light pulse is produced by the stopping muon which is deteted and amplified by photo multiplier.

The source of muons in our lab is the interaction of proton with nucli principally nirtrogen, oxygen, and argon.