OBSERVATION OF MUONIUM ATOM IN SOLID NITROGEN

Muonium (mu+e- or Mu, a light isotope of the H atom) has been directly observed for the first time in solid nitrogen (N-14(2)). In both alph a-N2 and beta-N2, muonium is manifest as a long-lived mu+SR spin prece ssion signal at the characteristic Mu frequency in a weak transverse m agnetic field. The temperature dependence of this signal's relaxation rate T2(-1) indicates that the diffusion of Mu involves quantum tunnel ing; a theory is presented that qualitatively explains T2(-1) (T) in n itrogen.