Reheating Closed String Inflation

TL;DR

This paper investigates reheating mechanisms in closed string inflation models, highlighting challenges in coupling to the Standard Model and the potential for hidden sectors to produce dark matter candidates across a wide mass spectrum.

Contribution

It analyzes how UV completion constraints influence reheating in closed string inflation, especially in N-flation, and explores hidden sector reheating and dark matter implications.

Findings

Coupling the inflaton to the Standard Model is challenging.

Hidden sectors are typically reheated instead of the Standard Model.

Relic particles from hidden sectors can serve as dark matter candidates.

Abstract

Protecting the inflationary potential from quantum corrections typically requires symmetries that constrain the form of couplings of the inflaton to other sectors. We will explore how these restrictions affect reheating in models with UV completions. In particular, we look at how reheating occurs when inflation is governed by closed strings, using N-flation as an example. We find that coupling the inflaton preferentially to the Standard Model is difficult, and hidden sectors are typically reheated. Observational constraints are only met by a fraction of the models. In some working models, relativistic relics in the hidden sector provide dark matter candidates with masses that range from keV to PeV, with lighter masses being preferred.