SUSY constraints, relic density, and very early universe

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.

Robustness of dark matter constraints and interplay with collider searches for New Physics

“…This hypothesis can however be falsified in many extensions of the standard model of cosmology [34][35][36][37][38]. Similarly, entropy injection or non-thermal production of dark matter particles can modify the relic density [39][40][41][42][43]. These modifications of the standard model of cosmology can result in a change of the relic density by orders of magnitude, but are more likely to increase it.…”

Constraints on the CP-Violating MSSM

“…The points above the cosmological measurements have mostly bino-like neutralino, and the two strips below the dark matter line correspond to wino and higgsino-like neutralinos. The points above the line can be considered as excluded, since they lead to an overdensity of dark matter, provided the pre-Big Bang nucleosynthesis period is dominated by radiation [22,23], so that most of the bino-like neutralinos are excluded. CP violation allows for more such points to sur- vive, without changing the picture.…”

Dark Matter in a twisted bottle

“…Then, if dark energy were the dominant component at the time of the relic freeze-out, it would result in an acceleration of the expansion of the Universe, which would lead to an earlier freeze-out and a much larger relic density [8][9][10][11][12]. Finally, entropy generation at the time of freeze-out, for example due to the decay of a late inflaton, can also lead to an increase -or a decreaseof the relic density [13][14][15][16][17]. These effects are however limited by Big-Bang nucleosynthesis constraints, but using SuperIso Relic [18,19] and AlterBBN [20], it can be verified that they can nevertheless lead to an increase of three orders of magnitudes or more of the relic density while still being compatible with BBN constraints.…”