SUSY Constraints, Relic Density, and Very Early Universe

TL;DR

This paper examines how early Universe cosmological assumptions affect supersymmetric relic density calculations and emphasizes the importance of clear model context for interpreting constraints, with implications for future collider discoveries.

Contribution

It introduces parametrizations for early Universe effects on relic density and highlights the necessity of specifying cosmological models in SUSY constraints.

Findings

Relic density calculations are highly sensitive to early Universe conditions.

Modifications in expansion rate and entropy can significantly alter SUSY parameter constraints.

Constraints from Big-Bang nucleosynthesis limit early Universe scenarios.

Abstract

The sensitivity of the lightest supersymmetric particle relic density calculation to different cosmological scenarios is discussed. In particular, we investigate the effects of modifications of the expansion rate and of the entropy content in the Early Universe. These effects, even with no observational consequences, can still drastically modify the relic density constraints on the SUSY parameter space. We suggest general parametrizations to evaluate such effects, and derive also constraints from Big-Bang nucleosynthesis. We show that using the relic density in the context of supersymmetric constraints requires a clear statement of the underlying cosmological model assumptions to avoid misinterpretations. On the other hand, we note that combining the relic density calculation with the eventual future discoveries at the LHC will hopefully shed light on the Very Early Universe properties.