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Title: New production mechanism for keV sterile neutrino Dark Matter by decays of frozen-in scalars

We propose a new production mechanism for keV sterile neutrino Dark Matter. In our setting, we assume the existence of a scalar singlet particle which never entered thermal equilibrium in the early Universe, since it only couples to the Standard Model fields by a really small Higgs portal interaction. For suitable values of this coupling, the scalar can undergo the so-called freeze-in process, and in this way be efficiently produced in the early Universe. These scalars can then decay into keV sterile neutrinos and produce the correct Dark Matter abundance. While similar settings in which the scalar does enter thermal equilibrium and then freezes out have been studied previously, the mechanism proposed here is new and represents a versatile extension of the known case. We perform a detailed numerical calculation of the DM production using a set of coupled Boltzmann equations, and we illustrate the successful regions in the parameter space. Our production mechanism notably can even work in models where active-sterile mixing is completely absent.
Authors:
 [1] ;  [2] ;  [3]
  1. Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ (United Kingdom)
  2. Departament d'Estructura i Constituents de la Matèria and Institut de Ciències del Cosmos, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain)
  3. Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)
Publication Date:
OSTI Identifier:
22370628
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 03; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; BOLTZMANN EQUATION; HIGGS BOSONS; HIGGS MODEL; KEV RANGE; NEUTRINOS; NONLUMINOUS MATTER; PARTICLE DECAY; SCALARS; SPACE; STANDARD MODEL; THERMAL EQUILIBRIUM; UNIVERSE