RADIATIVE B-MESON DECAY IN SUPERSYMMETRIC MODELS

The rare decay b --> sgamma is discussed in supersymmetric standard models based on grand unification and N = 1 supergravity. The interaction lagrangians which induce the generation changings for the quarks are given in explicit forms. It is shown that the one-loop diagrams with the charginos generally make a larger contribution to the decay rate than those with the gluinos and with the neutralinos. The inclusive rate for the radiative B-meson decay is enhanced or reduced from the standard model prediction in sizable ranges of the parameter space.