Asymmetric Dark Matter: Residual Annihilations and Self-Interactions

Baldes, Iason; Panci, Paolo; Petraki, Kalliopi; Sala, Filippo; Cirelli, Marco; Taoso, Marco

Preprint/Report

PUBDB-2017-13972

Asymmetric Dark Matter: Residual Annihilations and Self-Interactions

Baldes, I. (Corresponding author)DESY* ; Cirelli, M. ; Panci, P. ; Petraki, K. ; Sala, F.DESY* ; Taoso, M.

2017

[10.3204/PUBDB-2017-13972]

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Please use a persistent id in citations: doi:10.3204/PUBDB-2017-13972

Report No.: CERN-TH-2017-272; DESY-17-232; arXiv:1712.07489

Abstract: The putative discrepancies between observations of the small scale galactic structure and the predictions of collisionless cold dark matter may be resolved if dark matter possesses sizable self-interactions. The coupling of dark matter to a light force mediator can ensure sufficiently large self-interactions, reproduce the observed relic abundance via freeze-out and satisfy constraints from cluster mergers and direct detection. However, strong bounds on such scenarios still arise from indirect detection, particularly from the CMB and $\gamma$-rays observations. As a simple way to alleviate this tension, we consider the possibility of dark matter possessing a particle-antiparticle asymmetry. First, we point out that, contrary to the common perception, significant residual annihilations occur even for highly asymmetric dark matter coupled to light force carriers. We compute the indirect detection signals and corresponding constraints from the CMB, $\gamma$-ray, neutrino and antiproton searches. On this basis, we then identify the parameter space where the dark matter self-interactions are significant while evading the above bounds. While the direct detection constraints are not suppressed by the asymmetry, we show that they do not yet rule out this scenario, but provide a method for confirming it.

Note: 9 pages, 4 figures

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