Shifted $\mu$-hybrid inflation, gravitino dark matter, and observable gravity waves

TL;DR

This paper explores a supersymmetric hybrid inflation model based on a specific gauge symmetry, addressing monopole inflation, the origin of the MSSM $$ term, and the potential for observable gravitational waves, with implications for gravitino dark matter.

Contribution

It presents a realistic SUSY hybrid inflation model incorporating gauge symmetry breaking, the MSSM $$ term generation, and predictions for observable gravity waves and gravitino dark matter.

Findings

Inflationary trajectory inflates away primordial monopoles.

Parameter space regions yield gravitino dark matter.

Predicted tensor-to-scalar ratio $r$ is between $10^{-4}$ and $10^{-3}$.

Abstract

We investigate supersymmetric hybrid inflation in a realistic model based on the gauge symmetry $SU(4)_c \times SU(2)_L \times SU(2)_R$. The minimal supersymmetric standard model (MSSM) $\mu$ term arises, following Dvali, Lazarides, and Shafi, from the coupling of the MSSM electroweak doublets to a gauge singlet superfield which plays an essential role in inflation. The primordial monopoles are inflated away by arranging that the $SU(4)_c \times SU(2)_L \times SU(2)_R$ symmetry is broken along the inflationary trajectory. The interplay between the (above) $\mu$ coupling, the gravitino mass, and the reheating following inflation is discussed in detail. We explore regions of the parameter space that yield gravitino dark matter and observable gravity waves with the tensor-to-scalar ratio $r \sim 10^{-4}-10^{-3}$.