Non-thermal Dark Matter and the Moduli Problem in String Frameworks

TL;DR

This paper investigates how string theory models, specifically G2-MSSM, can resolve the cosmological moduli and gravitino problems while producing the correct amount of non-thermal dark matter through moduli decay.

Contribution

It provides a detailed analysis of moduli decay rates in G2-MSSM models, demonstrating their compatibility with cosmological constraints and their ability to produce viable dark matter relic density.

Findings

Late decaying moduli satisfy BBN constraints.

G2-MSSM predicts non-thermal wino LSPs with correct relic density.

Moduli decay avoids the gravitino problem.

Abstract

We address the cosmological moduli/gravitino problems and the issue of too little thermal but excessive non-thermal dark matter from the decays of moduli. The main examples we study are the G2-MSSM models arising from M theory compactifications, which allow for a precise calculation of moduli decay rates and widths. We find that the late decaying moduli satisfy both BBN constraints and avoid the gravitino problem. The non-thermal production of wino LSPs, which is a prediction of G2-MSSM models, gives a relic density of about the right order of magnitude.