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Title: Non-Gaussian isocurvature perturbations in dark radiation

Abstract

We study non-Gaussian properties of the isocurvature perturbations in the dark radiation, which consists of the active neutrinos and extra light species, if exist. We first derive expressions for the bispectra of primordial perturbations which are mixtures of curvature and dark radiation isocurvature perturbations. We also discuss CMB bispectra produced in our model and forecast CMB constraints on the non-linearity parameters based on the Fisher matrix analysis. Some concrete particle physics motivated models are presented in which large isocurvature perturbations in extra light species and/or the neutrino density isocurvature perturbations as well as their non-Gaussianities may be generated. Thus detections of non-Gaussianity in the dark radiation isocurvature perturbation will give us an opportunity to identify the origin of extra light species and lepton asymmetry.

Authors:
; ;  [1];  [2];  [3]
  1. Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan)
  2. Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 277-8568 (Japan)
  3. Department of Physics and Astrophysics, Nagoya University, Nagoya 464-8602 (Japan)
Publication Date:
OSTI Identifier:
22279846
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2012; Journal Issue: 07; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; ASYMMETRY; COSMOLOGY; DENSITY; DISTURBANCES; NEUTRINOS; RELICT RADIATION

Citation Formats

Kawakami, Etsuko, Kawasaki, Masahiro, Miyamoto, Koichi, Nakayama, Kazunori, and Sekiguchi, Toyokazu. Non-Gaussian isocurvature perturbations in dark radiation. United States: N. p., 2012. Web. doi:10.1088/1475-7516/2012/07/037.
Kawakami, Etsuko, Kawasaki, Masahiro, Miyamoto, Koichi, Nakayama, Kazunori, & Sekiguchi, Toyokazu. Non-Gaussian isocurvature perturbations in dark radiation. United States. https://doi.org/10.1088/1475-7516/2012/07/037
Kawakami, Etsuko, Kawasaki, Masahiro, Miyamoto, Koichi, Nakayama, Kazunori, and Sekiguchi, Toyokazu. 2012. "Non-Gaussian isocurvature perturbations in dark radiation". United States. https://doi.org/10.1088/1475-7516/2012/07/037.
@article{osti_22279846,
title = {Non-Gaussian isocurvature perturbations in dark radiation},
author = {Kawakami, Etsuko and Kawasaki, Masahiro and Miyamoto, Koichi and Nakayama, Kazunori and Sekiguchi, Toyokazu},
abstractNote = {We study non-Gaussian properties of the isocurvature perturbations in the dark radiation, which consists of the active neutrinos and extra light species, if exist. We first derive expressions for the bispectra of primordial perturbations which are mixtures of curvature and dark radiation isocurvature perturbations. We also discuss CMB bispectra produced in our model and forecast CMB constraints on the non-linearity parameters based on the Fisher matrix analysis. Some concrete particle physics motivated models are presented in which large isocurvature perturbations in extra light species and/or the neutrino density isocurvature perturbations as well as their non-Gaussianities may be generated. Thus detections of non-Gaussianity in the dark radiation isocurvature perturbation will give us an opportunity to identify the origin of extra light species and lepton asymmetry.},
doi = {10.1088/1475-7516/2012/07/037},
url = {https://www.osti.gov/biblio/22279846}, journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 07,
volume = 2012,
place = {United States},
year = {Sun Jul 01 00:00:00 EDT 2012},
month = {Sun Jul 01 00:00:00 EDT 2012}
}