Non-thermal Dark Matter in String Compactifications

TL;DR

This paper explores a non-thermal dark matter model within string theory's LARGE Volume Scenario, addressing key cosmological issues and demonstrating viable neutralino dark matter abundance across a range of masses.

Contribution

It presents a novel non-thermal dark matter model in string compactifications that resolves moduli and axion overproduction problems.

Findings

Achieves correct neutralino dark matter abundance for GeV to TeV masses.

Shows QCD axion contribution is negligible in overproduction cases.

Demonstrates multi-component dark matter scenarios are possible.

Abstract

Non-thermal cosmological histories are capable of greatly increasing the available parameter space of different particle physics dark matter (DM) models and are well-motivated by the ubiquity of late-decaying gravitationally coupled scalars in UV theories like string theory. A non-thermal DM model is presented in the context of LARGE Volume Scenarios in type IIB string theory. The model is capable of addressing both the moduli-induced gravitino problem as well as the problem of overproduction of axionic dark radiation and/or DM. We show that the right abundance of neutralino DM can be obtained in both thermal under and overproduction cases for DM masses between O(GeV) to O(TeV). In the latter case the contribution of the QCD axion to the relic density is totally negligible, while in the former case it can be comparable to that of the neutralino thus resulting in a multi-component DM scenario.