Constraints on Dark Matter Annihilation Cross Section in Scenarios of Brane-World and Quintessence

TL;DR

This paper explores how brane-world and quintessence cosmological models affect dark matter annihilation, constraining the annihilation cross section based on observed dark matter abundance and other physical bounds, and explaining recent cosmic ray anomalies.

Contribution

It provides new constraints on dark matter annihilation cross sections within brane-world and quintessence scenarios, linking cosmological models to observational anomalies.

Findings

Both scenarios allow large annihilation cross sections.

Constraints from BBN and unitarity limit cross section values.

Models can explain recent cosmic ray excesses.

Abstract

We investigate the dark matter annihilation in the brane-world and quintessence scenarios, in which the modified cosmological expansion rate can enhance the thermal relic density of dark matter. According to the observed dark matter abundance, we constrain the thermally averaged annihilation cross section <\sigma v> in these two scenarios. In addition, the big bang nucleosynthesis and the partial-wave unitarity are also used to place bounds on <\sigma v>. It is found that both scenarios can lead to a large annihilation cross section, so they can be used to explain the recent PAMELA, ATIC and PPB-BETS anomalies.