Inflation in Supersymmetric SU(5)

TL;DR

This paper investigates supersymmetric SU(5) inflation models, emphasizing non-minimal scenarios like shifted hybrid inflation to address monopole issues and achieve spectral index values consistent with WMAP data, while discussing implications for particle physics.

Contribution

It introduces a non-minimal SUSY SU(5) inflation model with supergravity corrections that aligns with observational data and solves the monopole problem.

Findings

Supergravity corrections are essential for matching the spectral index n_s ~ 0.96.

The tensor-to-scalar ratio r is predicted to be very small, less than 10^{-5}.

Adding light vector-like particles preserves gauge coupling unification.

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.