Limits on the top quark mass within the frame of the minimal superstrings inspired model

We study the process of spontaneous R parity breaking in minimal stringy models. In these models the top quark mass is bounded from below to allow the spontaneous breaking of SU (2)_L × U (1)_Y. On the other hand the requirement of stability for the neutral potential which is sufficient to avoid R parity breaking, gives us an upper bound. Allowed values for the top quark mass remain between 70 and 95 GeV, if supersymmetry breaking is triggered by gaugino masses.