Inflationary Predictions and Moduli Masses

TL;DR

This paper explores how moduli fields in supergravity/string inflation models influence post-inflationary history and affect the predictions of CMB observables, highlighting the importance of moduli masses.

Contribution

It demonstrates the sensitivity of inflationary predictions like $n_s$ and $r$ to moduli masses, linking particle physics with cosmological observations.

Findings

Moduli masses alter the number of e-foldings $N_k$ relevant for CMB.

CMB observables $n_s$ and $r$ depend on moduli masses.

Post-inflationary history modifications impact inflationary model constraints.

Abstract

A generic feature of inflationary models in supergravity/string constructions is vacuum misalignment for the moduli fields. The associated production of moduli particles leads to an epoch in the post-inflationary history in which the energy density is dominated by cold moduli particles. This modification of the post-inflationary history implies that the preferred range for the number of e-foldings between horizon exit of the modes relevant for CMB observations and the end of inflation $(N_k)$ depends on moduli masses. This in turn implies that the precision CMB observables $n_s$ and $r$ are sensitive to moduli masses. We analyse this sensitivity for some representative models of inflation and find the effect to be highly relevant for confronting inflationary models with observations.