Axion, mu Term, and Supersymmetric Hybrid Inflation

TL;DR

This paper demonstrates how supersymmetric hybrid inflation can be integrated with axion physics and the mu problem, ensuring consistency with observational limits and providing a framework for dark matter and leptogenesis.

Contribution

It presents a realistic model linking supersymmetric hybrid inflation, axion physics, and the mu problem, with detailed analysis of scalar fields and cosmological implications.

Findings

Scalar spectral index n_s ≈ 0.96-0.97

Tensor-to-scalar ratio r below observable range

Axions and/or lightest supersymmetric particles can account for dark matter

Abstract

We show how successful supersymmetric hybrid inflation is realized in realistic models where the resolution of the minimal supersymmetric standard model mu problem is intimately linked with axion physics. The scalar fields that accompany the axion, such as the saxion, are closely monitored during and after inflation to ensure that the axion isocurvature perturbations lie below the observational limits. The scalar spectral index n_s is about 0.96 - 0.97, while the tensor-to-scalar ratio r, a canonical measure of gravity waves, lies well below the observable range in our example. The axion domain walls are inflated away, and depending on the axion decay constant f_a and the magnitude of the mu parameter, the axions and/or the lightest supersymmetric particle compose the dark matter in the universe. Non-thermal leptogenesis is naturally implemented in this class of models.