  It is widely believed that minimal supersymmetric SU(5) GUTs have been
excluded by the SuperKamiokande bound for the proton decay rate. In the minimal
model, however, the theoretical prediction assumes unification of Yukawa
couplings, Y_d=Y_e, which is known to be badly violated. We analyze the
implications of this fact for the proton decay rate. In a consistent SU(5)
model with higher dimensional operators, where SU(5) relations among Yukawa
couplings hold, the proton decay rate can be several orders of magnitude
smaller than the present experimental bound.

High Energy Physics - Phenomenology