RESIDUAL POLARIZATION OF NEGATIVE MUONS IMPLANTED IN C-60 AND K3C60

Negative muons captured by atoms with zero nuclear spin usually retain about 1/6 of their initial spin polarization P-0 after cascading down to their lowest Bohr orbital. This is particularly observed for mu(-) implanted into graphite and diamond. However, mu(-) implanted into a powder of the fullerene C-60 are found to show essentially zero residu al polarization. A residual polarization of similar to P-0/6 is again seen in metallic K3C60. We speculate that these results are to be expl ained on the basis of hyperfine effects after completion of the muonic cascade.