Lost muon polarization in liquids studied by longitudinal decoupling field and muon spin resonance techniques

Three different techniques of muon spin science, μ + SR, longitudinal μ + spin decoupling and μ + spin resonance, have been applied in search for the origin of the occurence of the “lost polarization,” which is the muon spin polarization unobservable either as coherent diamagnetic muon, muonium and muonium-substituted radicals. The results indicate that the lost polarization involves fast reactions of muonium on the time scale faster that about 1 ns by, most probably, spin exchange reactions, but some contribution from chemical reaction of muonium also seems probable. The μ + spin decoupling experiment has also revealed that there is a small amount (∼10%) of thermal muonium atoms in CCl 4 .