Proton Life-Time Problem In Finite Grand Unified Theories
  We study proton decay in finite supersymmetric SU(5) grand unified theories. We find that the dimension-five operators due to color triplet higgsino induce too rapid a proton decay. This behaviour can be traced to the large Yukawa couplings to the first generation that are necessary for finiteness. 
N. Deshpande, Xiao-Gang He and E. Keith