  We exploit the measured branching ratio for $b \rightarrow s\gamma$ to derive
lower limits on the sparticle and Higgs masses in the minimal string
unification models. For the LSP('bino'), chargino and the lightest Higgs, these
turn out to be 50, 90 and 75 GeV respectively. Taking account of the upper
bounds on the mass spectrum from the LSP relic abundance, we estimate the
direct detection rate for the latter to vary from 10^{-1} to 10^{-4}
events/kg/day. The muon flux, produced by neutrinos from the annihilating
LSP's, varies in the range 10^{-2} - 10^{-9} muons/m^2/day.
