Constraint on the Photino Mass from Cosmology

A lower bound for the photino mass m \~{} as a function of the spin-0 fermion superpartner mass m \~{f} is derived as an extension of the calculation of Lee and Weinberg. The Majorana nature of the photino induces a p-wave threshold for annihilation \~{} \~{} into light fermions, and leads to a rather unexpected form for the bound: for 25 GeVm \~{f}45 GeV, ({m \~{}) }₌₈₍m_=1. 8 GeV; for m \~{f}>45 GeV, ({m \~{}) }₌₈₍ increases approximately linearly with m \~{f} to a value of 20 GeV when m \~{f}=100 GeV.