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Title: Production and evolution of perturbations of sterile neutrino dark matter

Abstract

Sterile neutrinos, fermions with no standard model couplings [SU(2) singlets], are predicted by most extensions of the standard model, and may be the dark matter. I describe the nonthermal production and linear perturbation evolution in the early universe of this dark matter candidate. I calculate production of sterile neutrino dark matter including effects of Friedmann dynamics dictated by the quark-hadron transition and particle population, the alteration of finite temperature effective mass of active neutrinos due to the presence of thermal leptons, and heating of the coupled species due to the disappearance of degrees of freedom in the plasma. These effects leave the sterile neutrinos with a nontrivial momentum distribution. I also calculate the evolution of sterile neutrino density perturbations in the early universe through the linear regime and provide a fitting function form for the transfer function describing the suppression of small-scale fluctuations for this warm dark matter candidate. The results presented here differ quantitatively from previous work due to the inclusion of the relevant physical effects during the production epoch.

Authors:
 [1]
  1. Theoretical Division, Los Alamos National Laboratory, MS B285, Los Alamos, New Mexico 87545 (United States)
Publication Date:
OSTI Identifier:
20782610
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 73; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevD.73.063506; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COSMOLOGY; DEGREES OF FREEDOM; DISTRIBUTION; DISTURBANCES; EFFECTIVE MASS; FLUCTUATIONS; NEUTRINOS; NONLUMINOUS MATTER; QUARK-HADRON INTERACTIONS; STANDARD MODEL; SU-2 GROUPS; TRANSFER FUNCTIONS; UNIVERSE

Citation Formats

Abazajian, Kevork. Production and evolution of perturbations of sterile neutrino dark matter. United States: N. p., 2006. Web. doi:10.1103/PHYSREVD.73.063506.
Abazajian, Kevork. Production and evolution of perturbations of sterile neutrino dark matter. United States. doi:10.1103/PHYSREVD.73.063506.
Abazajian, Kevork. Wed . "Production and evolution of perturbations of sterile neutrino dark matter". United States. doi:10.1103/PHYSREVD.73.063506.
@article{osti_20782610,
title = {Production and evolution of perturbations of sterile neutrino dark matter},
author = {Abazajian, Kevork},
abstractNote = {Sterile neutrinos, fermions with no standard model couplings [SU(2) singlets], are predicted by most extensions of the standard model, and may be the dark matter. I describe the nonthermal production and linear perturbation evolution in the early universe of this dark matter candidate. I calculate production of sterile neutrino dark matter including effects of Friedmann dynamics dictated by the quark-hadron transition and particle population, the alteration of finite temperature effective mass of active neutrinos due to the presence of thermal leptons, and heating of the coupled species due to the disappearance of degrees of freedom in the plasma. These effects leave the sterile neutrinos with a nontrivial momentum distribution. I also calculate the evolution of sterile neutrino density perturbations in the early universe through the linear regime and provide a fitting function form for the transfer function describing the suppression of small-scale fluctuations for this warm dark matter candidate. The results presented here differ quantitatively from previous work due to the inclusion of the relevant physical effects during the production epoch.},
doi = {10.1103/PHYSREVD.73.063506},
journal = {Physical Review. D, Particles Fields},
number = 6,
volume = 73,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • The generation of lepton asymmetry below the electroweak scale has a considerable impact on production of dark matter sterile neutrinos. Oscillations or decays of the heavier sterile neutrinos in the neutrino minimal standard model can give rise to the requisite lepton asymmetry, provided the masses of the heavier neutrinos are sufficiently degenerate. We study the renormalization group evolution of the mass difference of these singlet fermions to understand the degree of necessary fine-tuning. We construct an example of the model that can lead to a technically natural realization of this low-energy degeneracy.
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