R-Symmetry and Gravitino Abundance

TL;DR

This paper explores how R-symmetry in supersymmetry breaking sectors affects gravitino production, showing that R-symmetry can suppress gravitino abundance and make it a viable dark matter candidate with relic density insensitive to reheating temperature.

Contribution

It demonstrates that R-symmetry restoration in the early universe suppresses gravitino production, providing a new perspective on gravitino dark matter and its relic abundance.

Findings

R-symmetry suppresses gaugino masses and gravitino production.

Gravitino relic abundance is insensitive to reheating temperature.

Gravitino can account for dark matter under certain parameters.

Abstract

Supersymmetry breaking sectors generically have an approximate global U(1) $R$-symmetry. Thermal effects tend to restore the $R$-symmetry in the reheated early universe. We revisit the gravitino generation from the thermal plasma and we argue that an $R$-symmetric phase suppresses the gaugino masses and thereby the production of the helicity $\pm 1/2$ gravitino component. For reasonable values of the hidden sector parameters the gravitino can account for the dark matter of the universe with a relic abundance characterized by a remarkable insensitivity to the reheating temperature.