Asymmetric Dark Matter and Dark Radiation
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)
- Theory Division, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland)
- Instituto de Física Corpuscular, CSIC-Universitat de València, 22085, E-46071 Valencia (Spain)
- Max-Planck-Institut für Physik, Föhringer Ring 6, D-80805 München (Germany)
- Institut d'Astrophysique Spatiale, UMR8617, Universite Paris-Sud and CNRS, Bat. 121, Orsay F-91405 (France)
Asymmetric Dark Matter (ADM) models invoke a particle-antiparticle asymmetry, similar to the one observed in the Baryon sector, to account for the Dark Matter (DM) abundance. Both asymmetries are usually generated by the same mechanism and generally related, thus predicting DM masses around 5 GeV in order to obtain the correct density. The main challenge for successful models is to ensure efficient annihilation of the thermally produced symmetric component of such a light DM candidate without violating constraints from collider or direct searches. A common way to overcome this involves a light mediator, into which DM can efficiently annihilate and which subsequently decays into Standard Model particles. Here we explore the scenario where the light mediator decays instead into lighter degrees of freedom in the dark sector that act as radiation in the early Universe. While this assumption makes indirect DM searches challenging, it leads to signals of extra radiation at BBN and CMB. Under certain conditions, precise measurements of the number of relativistic species, such as those expected from the Planck satellite, can provide information on the structure of the dark sector. We also discuss the constraints of the interactions between DM and Dark Radiation from their imprint in the matter power spectrum.
- OSTI ID:
- 22279842
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2012, Issue 07; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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