Inflation in Supersymmetric SU(5)

Abstract

We analyze the adjoint field inflation in supersymmetric (SUSY) SU(5) model. In minimal SUSY SU(5) hybrid inflation monopoles are produced at the end of inflation. We therefore explore the non-minimal model of inflation based on SUSY SU(5), like shifted hybrid, which provides a natural solution for the monopole problem. We find that the supergravity corrections with non-minimal Kahler potential are crucial to realize the central value of the scalar spectral index n_s ~ 0.96 consistent with the seven year WMAP data. The tensor to scalar ratio r is quite small, taking on values r < 10^{-5}. Due to R-symmetry massless SU(3) octet and SU(2) triplet Higgs bosons are present and could spoil for gauge coupling unification. To keep gauge coupling unification intact, light vector-like particles are added which are expected to be observed at LHC.

16 pages