A-term inflation and the MSSM

TL;DR

This paper investigates A-term inflation within the MSSM framework, analyzing parameter spaces for different powers p, and discusses the conditions under which observed spectral properties can be achieved, highlighting fine-tuning issues.

Contribution

It explores the viability of A-term inflation in the MSSM with specific superpotential forms, identifying parameter constraints and potential extensions to support inflation.

Findings

For p=6, observed spectrum achieved with soft mass ~100 GeV.

For p=3, coupling constants must be extremely small (~10^{-9} to 10^{-12}).

Fine-tuning of m/A ratio may be justified environmentally.

Abstract

The parameter space for A-term inflation is explored with $W=\lambda_p \phi^p/(p M_P^{p-3})$. With p=6 and \lambda_p~1, the observed spectrum and spectral tilt can be obtained with soft mass of order 10^2 GeV but not with a much higher mass. The case p=3 requires \lambda_p~10^{-9} to 10^{-12}. The ratio m/A requires fine-tuning, which may be justified on environmental grounds. An extension of the MSSM to include non-renormalizable terms and/or Dirac neutrino masses might support either A-term inflation or modular inflation.