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Title: Daughters mimic sterile neutrinos (almost!) perfectly

Abstract

Since only recently, cosmological observations are sensitive to hot dark matter (HDM) admixtures with sub-eV mass, m{sub hdm}{sup eff} < eV, that are not fully-thermalised, Δ N{sub eff} < 1. We argue that their almost automatic interpretation as a sterile neutrino species is neither from theoretical nor practical parsimony principles preferred over HDM formed by decay products (daughters) of an out-of-equilibrium particle decay. While daughters mimic sterile neutrinos in N{sub eff} and m{sub hdm}{sup eff}, there are opportunities to assess this possibility in likelihood analyses. Connecting cosmological parameters and moments of momentum distribution functions, we show that—also in the case of mass-degenerate daughters with indistinguishable main physical effects—the mimicry breaks down when the next moment, the skewness, is considered. Predicted differences of order one in the root-mean-squares of absolute momenta are too small for current sensitivities.

Authors:
 [1]
  1. CCPP, Department of Physics, New York University, New York, NY 10003 (United States)
Publication Date:
OSTI Identifier:
22375861
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 09; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DAUGHTER PRODUCTS; DISTRIBUTION FUNCTIONS; EQUILIBRIUM; EV RANGE; MASS; NEUTRINOS; NONLUMINOUS MATTER; PARTICLE DECAY; SENSITIVITY

Citation Formats

Hasenkamp, Jasper, E-mail: Jasper.Hasenkamp@nyu.edu. Daughters mimic sterile neutrinos (almost!) perfectly. United States: N. p., 2014. Web. doi:10.1088/1475-7516/2014/09/048.
Hasenkamp, Jasper, E-mail: Jasper.Hasenkamp@nyu.edu. Daughters mimic sterile neutrinos (almost!) perfectly. United States. doi:10.1088/1475-7516/2014/09/048.
Hasenkamp, Jasper, E-mail: Jasper.Hasenkamp@nyu.edu. Mon . "Daughters mimic sterile neutrinos (almost!) perfectly". United States. doi:10.1088/1475-7516/2014/09/048.
@article{osti_22375861,
title = {Daughters mimic sterile neutrinos (almost!) perfectly},
author = {Hasenkamp, Jasper, E-mail: Jasper.Hasenkamp@nyu.edu},
abstractNote = {Since only recently, cosmological observations are sensitive to hot dark matter (HDM) admixtures with sub-eV mass, m{sub hdm}{sup eff} < eV, that are not fully-thermalised, Δ N{sub eff} < 1. We argue that their almost automatic interpretation as a sterile neutrino species is neither from theoretical nor practical parsimony principles preferred over HDM formed by decay products (daughters) of an out-of-equilibrium particle decay. While daughters mimic sterile neutrinos in N{sub eff} and m{sub hdm}{sup eff}, there are opportunities to assess this possibility in likelihood analyses. Connecting cosmological parameters and moments of momentum distribution functions, we show that—also in the case of mass-degenerate daughters with indistinguishable main physical effects—the mimicry breaks down when the next moment, the skewness, is considered. Predicted differences of order one in the root-mean-squares of absolute momenta are too small for current sensitivities.},
doi = {10.1088/1475-7516/2014/09/048},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 09,
volume = 2014,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 2014},
month = {Mon Sep 01 00:00:00 EDT 2014}
}