Sterile neutrino dark matter as a consequence of nuMSM-induced lepton asymmetry

Abstract

It has been pointed out in ref.[1] that in the nuMSM (Standard Model extended by three right-handed neutrinos with masses smaller than the electroweak scale), there is a corner in the parameter space where CP-violating resonant oscillations among the two heaviest right-handed neutrinos continue to operate below the freeze-out temperature of sphaleron transitions, leading to a lepton asymmetry which is considerably larger than the baryon asymmetry. Consequently, the lightest right-handed (``sterile'') neutrinos, which may serve as dark matter, are generated through an efficient resonant mechanism proposed by Shi and Fuller [2]. We re-compute the dark matter relic density and non-equilibrium momentum distribution function in this situation with quantum field theoretic methods and, confronting the results with existing astrophysical data, derive bounds on the properties of the lightest right-handed neutrinos. Our spectra can be used as an input for structure formation simulations in warm dark matter cosmologies, for a Lyman-alpha analysis of the dark matter distribution on small scales, and for studying the properties of haloes of dwarf spheroidal galaxies.

25 pages. v2: many clarifications and references added; published version

References in corpus (4)

• The Standard Model Higgs boson as the inflaton
• How cold is cold dark matter? Small scales constraints from the flux power spectrum of the high-redshift Lyman-alpha forest
• Constraints on dark matter particles from theory, galaxy observations and N-body simulations
• Sterile Neutrinos as the Warm Dark Matter in the Type II Seesaw Model

Cited by in corpus (7)

• Leptogenesis
• A lower bound on the mass of Dark Matter particles
• Realistic sterile neutrino dark matter with keV mass does not contradict cosmological bounds
• Right-handed neutrino magnetic moments
• Inflaton mass in the nuMSM inflation
• Constraints on neutrino masses from WMAP5 and BBN in the lepton asymmetric universe
• Sterile neutrinos in cosmology and how to find them in the lab