Minimal supersymmetric SU(5) theory and proton decay: where do we stand?
  We review the situation regarding d=5 proton decay in the minimal supersymmetric SU(5) GUT. The minimal theory is defined as the theory with the minimal matter and Higgs content all the way up to the Planck scale; of course, this allows for the possible presence of Planck induced physics. It can be said that either higher dimensional operators must be present or/and some fine-tuning of O(1%) of the Higgs mass must be tolerated in order to save the theory. 
Borut Bajc, Pavel Fileviez Perez and Goran Senjanovic