Improved electroweak phase transition with subdominant inert doublet dark matter
Abstract
The inert doublet dark matter model has recently gained attention as a possible means of facilitating a strongly firstorder electroweak phase transition (EWPT), as needed for baryogenesis. We extend previous results by considering the regime where the DM is heavier than half the Higgs mass, and its relic density is determined by annihilation into W, Z and Higgs bosons. We find a large natural region of parameter space where the EWPT is strongly first order, while the lightest inert doublet state typically contributes only 0.1%3% of the total dark matter. Despite this small density, its interactions with nucleons are strong enough to be directly detectable given a factor of 5 improvement over the current sensitivity of XENON100. A 10% increase in the branching ratio for Higgs decays to two photons is predicted.
 Publication:

Physical Review D
 Pub Date:
 April 2013
 DOI:
 10.1103/PhysRevD.87.071701
 arXiv:
 arXiv:1302.2614
 Bibcode:
 2013PhRvD..87g1701C
 Keywords:

 95.35.+d;
 12.60.Cn;
 Dark matter;
 Extensions of electroweak gauge sector;
 High Energy Physics  Phenomenology;
 Astrophysics  Cosmology and Extragalactic Astrophysics
 EPrint:
 4 pages, 5 figures