Gravitino dark matter production at finite temperature

TL;DR

This paper explores how the global U(1) R-symmetry affects gravitino dark matter production in gauge-mediated supersymmetry breaking models, showing conditions under which high reheating temperatures are compatible with observed dark matter abundance.

Contribution

It demonstrates the impact of R-symmetry restoration on gravitino production mechanisms and identifies parameter ranges allowing high reheating temperatures without overproducing gravitinos.

Findings

R-symmetry suppresses goldstino production from Standard Model scatterings.

High reheating temperatures can be achieved without gravitino overproduction.

Gravitino can be produced thermally or via decay of the GMSB spurion.

Abstract

The production and the final abundance of gravitino dark matter appear to depend crucially on the restoration of the global U(1) $R$-symmetry of GMSB sectors in a threefold way. An $R$-symmetric phase effectively suppresses the production of goldstinos from scatterings with the supersymmetric Standard Model particles and it generically initiates the goldstino production from the thermalized messenger particles. In addition, the GMSB spurion gets displaced from the zero temperature minimum and under certain conditions it dominates the energy density of the universe producing late entropy. We show that it is possible to have high enough reheating temperatures that thermal leptogenesis and thermal vacuum selection can be realized without gravitino overproduction. The gravitino dark matter can be produced either thermally or non-thermally. In the former case the messenger scale has to be less than about $10^6$ GeV with the gravitino relatively heavy, $m_{3/2}\geq {\cal O}(10)$ GeV. In the later case, the gravitino is generically produced by the decay of the GMSB spurion field a process that always takes place for large messenger scales. A connection of our results with current collider and observational data is performed.