Closing the Light Gluino Window in Supersymmetric Grand Unified Models

Abstract

We study the light gluino scenario giving special attention to constraints from the masses of the light CP-even neutral Higgs $m_h$, the lightest chargino $m_{χ^{\pm}_1}$, and the second lightest neutralino $m_{χ^0_2}$, and from the $b\rightarrow sγ$ decay. We find that minimal $N=1$ supergravity, with a radiatively broken electroweak symmetry group and universality of scalar and gaugino masses at the unification scale, is incompatible with the existence of a light gluino.