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Related papers: Cosmological Neutrino Background Revisited

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The neutrino energy density of the Universe can be conveniently parametrized in terms of the so-called effective number of neutrinos, N_nu^eff. This parameter enters in several cosmological observables. In particular it is an important…

Astrophysics · Physics 2016-08-30 G. Mangano , G. Miele , S. Pastor , M. Peloso

Neutrino self-interactions beyond the standard model have profound implications in astrophysics and cosmology. In this Letter, we study an uncharted scenario in which one of the three neutrino species has a mass smaller than the temperature…

High Energy Physics - Phenomenology · Physics 2025-10-30 Isaac R. Wang , Xun-Jie Xu , Bei Zhou

We compute the cosmological background radiation of gamma rays and neutrinos due to neutralino annihilation in evolving dark matter halos, assuming the observed dark matter is comprised of thermally excited neutralinos in the MSSM. The…

Astrophysics · Physics 2014-10-13 Dominik Elsaesser , Karl Mannheim

At present, the strongest upper limit on $\sum m_{\nu}$, the sum of neutrino masses, is from cosmological measurements. However, this bound assumes that the neutrinos are stable on cosmological timescales, and is not valid if the neutrino…

High Energy Physics - Phenomenology · Physics 2020-05-04 Zackaria Chacko , Abhish Dev , Peizhi Du , Vivian Poulin , Yuhsin Tsai

Cosmic microwave background (CMB) anisotropies and density fluctuations are calculated for flat cold dark matter (CDM) models with a wide range of parameters, i.e., $\Omega_0, h$ and $\Omega_B$ for both standard recombination and various…

Astrophysics · Physics 2009-10-22 Naoshi Sugiyama

Future cosmological measurements should enable the sum of neutrino masses to be determined indirectly through their effects on the expansion rate of the Universe and the clustering of matter. We consider prospects for the gravitationally…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-30 Rupert Allison , Paul Caucal , Erminia Calabrese , Joanna Dunkley , Thibaut Louis

We present cosmological constraints on the sum of neutrino masses as a function of the neutrino lifetime, in a framework in which neutrinos decay into dark radiation after becoming non-relativistic. We find that in this regime the cosmic…

High Energy Physics - Phenomenology · Physics 2022-08-18 Guillermo F. Abellán , Zackaria Chacko , Abhish Dev , Peizhi Du , Vivian Poulin , Yuhsin Tsai

The recent analysis of the cosmic microwave background data carried out by the WMAP team seems to show that the sum of the neutrino masses is <0.7 eV. However, this result is not model-independent, depending on precise assumptions on the…

Astrophysics · Physics 2009-11-10 Massimiliano Lattanzi

This article presents the first computation of the complete bispectrum of the cosmic microwave background temperature anisotropies arising from the evolution of all cosmic fluids up to second order, including neutrinos. Gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2010-07-14 Cyril Pitrou , Jean-Philippe Uzan , Francis Bernardeau

We compute the shift in the epoch of matter-radiation equality due to the possible existence of a different statistical (non-extensive) background. The shift is mainly caused by a different neutrino-photon temperature ratio. We then…

Astrophysics · Physics 2015-06-24 Diego F. Torres

A massive neutrino which decays after recombination (t > 10^{13} sec) into relativistic decay products produces an enhanced integrated Sachs-Wolfe effect, allowing constraints to be placed on such neutrinos from present cosmic microwave…

Astrophysics · Physics 2011-02-11 Manoj Kaplinghat , Robert E. Lopez , Scott Dodelson , Robert J. Scherrer

We investigate the radiative decay of the cosmic neutrino background, and its impact on the spectrum of the cosmic microwave background (CMB) that is known to be a nearly perfect black body. We derive exact formulae for the decay of a…

Within the context of hot big-bang cosmology, a cosmic background of presently low energy neutrinos is predicted to exist in concert with the photons of the cosmic background radiation. The number density of the cosmological neutrinos is of…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-01 Floyd W. Stecker

We obtain the equation governing the evolution of the cosmological gravitational-wave background, accounting for the presence of cosmic neutrinos, up to second order in perturbation theory. In particular, we focus on the epoch during…

Astrophysics · Physics 2009-02-23 A. Mangilli , N. Bartolo , S. Matarrese , A. Riotto

The cosmic microwave background anisotropy is sensitive to the slope and amplitude of primordial energy density and gravitational wave fluctuations, the baryon density, the Hubble constant, the cosmological constant, the ionization history,…

In the standard Big Bang cosmology the canonical value for the ratio of relic neutrinos to CMB photons is 9/11. Within the framework of the Standard Model of particle physics there are small corrections, in sum about 1%, due to slight…

Astrophysics · Physics 2009-10-30 Robert E. Lopez , Scott Dodelson , Andrew Heckler , Michael S. Turner

We consider heavy sterile neutrinos $\nu_s$, with mass in the range 10 MeV $\lesssim m_s \lesssim m_{\pi} \sim 135$ MeV, thermally produced in the early universe and freezing out after the QCD phase transition. The existence of these…

High Energy Physics - Phenomenology · Physics 2022-02-24 L. Mastrototaro

In this thesis we investigate several aspects related to the theory of fluctuations in the Cosmic Microwave Background. We develop a new algorithm to calculate the angular power spectrum of the anisotropies which is two orders of magnitude…

Astrophysics · Physics 2007-05-23 Matias Zaldarriaga

The Cosmic Microwave Background (CMB) yields information about our Universe at around 380 000 years after the Big Bang (BB). Due to the weak interaction of the neutrinos with matter the Cosmic Neutrino Background (CNB) should give…

Nuclear Theory · Physics 2017-03-08 Amand Faessler , Rastislav Hodak , Sergey Kovalenko , Fedor Simkovic