Mu spin exchange in polarized media

Abstract

The longitudinal relaxation of muonium due to spin exchange with a polarized spin 1/2 medium is investigated. Stochastic calculations assuming a Poisson process are carried out for the case where the initial muon spin polarization (P _μ=α_μ−β_μ), the electron spin polarization of muonium (P _M ), and the polarization of the electrons of the spin exchanging medium (P _G ) are along the external field. In a polarized medium, the muon spin polarization does not relax to zero but to a finite valueP _G which can be as large as 0.23 atT=4.2 K andB=30 kG. The relaxation rate defined as the rate of approach to the non-zero ‘baseline’ is independent ofP _μ,P _M , andP _G .