Muon spin rotation for positive muons

The number of electrons emitted in a given direction depends on the muon polarization, which can change in magnitude (spin relaxation) or in direction (spin rotation in a residual magnetic field). As the $\mu p$ atom quickly transfers to its F=0 spin singlet it is completely depolarized, so muon spin rotation is not an issue. in hydrogen is initially polarized with about 2/3 muonium and 1/3 free muon fraction [20]. The resulting $\mu SR$ effects lead to distortions of the time spectrum. The basic method for controlling SR effects has been suggested in our original proposal and later adopted for the two 1 ppm $\mu ^{+}$ proposals. By applying a transverse magnetic field of the order of 70 Gauss the fast muonium oscillation will be averaged out and the free muons will precess once per s. In the fit of the time distribution the SR oscillation parameters are largely uncorrelated to the lifetime, so that accurate information can be extracted for both.