Seesaw scale, unification, and proton decay

Abstract

We investigate a simple realistic grand unified theory based on the SU(5) gauge symmetry, which predicts an upper bound on the proton decay lifetime for the channels p→K+ν̄ and p→π+ν̄, i.e., τ(p→K+ν̄) 3.4×1035 and τ(p→π+ν) 1.7×1034 years, respectively. In this context, the neutrino masses are generated through the type I and type III seesaw mechanisms, and one predicts that the field responsible for type III seesaw must be light with a mass below 500 TeV. We discuss the testability of this theory at current and future proton decay experiments.