Minimal supersymmetric hybrid inflation, flipped SU(5) and proton decay

Abstract Minimal supersymmetric hybrid inflation utilizes a canonical Kahler potential and a renormalizable superpotential which is uniquely determined by imposing a U(1) R -symmetry. In computing the scalar spectral index n s we take into account modifications of the tree level potential caused by radiative and supergravity corrections, as well as contributions from the soft supersymmetry breaking terms with a negative soft mass-squared term allowed for the inflaton. All of these contributions play a role in realizing n s values in the range 0.96–0.97 preferred by WMAP. The U(1) R -symmetry plays an important role in flipped SU ( 5 ) by eliminating the troublesome dimension five proton decay. The proton decays into e + π 0 via dimension six operators arising from the exchange of superheavy gauge bosons with a lifetime of order 10 34 – 10 36 years.