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Related papers: Relic Neutrino Degeneracies and Their Impact on Co…

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A simple and natural extension of the standard Lambda cold dark matter ($\Lambda$CDM) model is to allow relic neutrinos to have finite chemical potentials. We confront this $\Lambda$CDM$\xi$ model, a $\Lambda$CDM with neutrino mass $M_\nu$…

High Energy Physics - Phenomenology · Physics 2025-09-03 Shek Yeung , Wangzheng Zhang , Ming-chung Chu

We consider some consequences of the presence of a cosmological lepton asymmetry in the form of neutrinos. A relic neutrino degeneracy enhances the contribution of massive neutrinos to the present energy density of the Universe, and…

High Energy Physics - Phenomenology · Physics 2009-10-31 Sergio Pastor , Julien Lesgourgues

We consider some consequences of the presence of a cosmological lepton asymmetry in the form of neutrinos. Relic neutrino degeneracy enhances the contribution of massive neutrinos to the present energy density of the Universe, and modifies…

High Energy Physics - Phenomenology · Physics 2016-08-25 Julien Lesgourgues , Sergio Pastor

It is well known that estimating cosmological parameters from cosmic microwave background (CMB) data alone results in a significant degeneracy between the total neutrino mass and several other cosmological parameters, especially the Hubble…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-28 Will Sutherland

We investigate the observational constraints on the cosmic neutrino background (CNB) given by the extended $\Lambda$CDM scenario ($\Lambda$CDM $+ N_{\rm eff} + \sum m_{\nu} + c^2_{\rm eff} + c^2_{\rm vis} + \xi_{\nu}$) using the latest…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-27 Rafael C. Nunes , Alexander Bonilla

We discuss the cosmological degeneracy between the Hubble parameter H(z), the age of the universe and cosmological parameters describing simple variations from the minimal LCDM model. We show that independent determinations of the Hubble…

Astrophysics · Physics 2014-11-18 Daniel G. Figueroa , Licia Verde , Raul Jimenez

When the perturbations forming the acoustic peaks of the cosmic microwave background (CMB) reentered the horizon and interacted gravitationally with all the matter, neutrinos presumably comprised 41% of the universe energy. CMB experiments…

Astrophysics · Physics 2015-06-24 Sergei Bashinsky

In this paper, we put constraints on neutrino properties such as mass $m_{\nu}$ and degeneracy parameters $\xi_i$ from WMAP5 data and light element abundances by using a Markov chain Monte Carlo (MCMC) approach. In order to take…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-22 Maresuke Shiraishi , Kazuhide Ichikawa , Kiyotomo Ichiki , Naoshi Sugiyama , Masahide Yamaguchi

We employ state-of-the art cosmological observables including supernova surveys and BAO information to provide constraints on the mass and mixing angle of a non-resonantly produced sterile neutrino species, showing that cosmology can…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-10 Aaron C. Vincent , Enrique Fernandez Martinez , Pilar Hernandez , Massimiliano Lattanzi , Olga Mena

We investigate the impact of neutrino statistical property on cosmology and the constraints imposed by cosmological data on neutrino statistics. Cosmological data from probes such as Cosmic Microwave Background(CMB) radiation and Baryon…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-03 YiCheng Dai , Wei Liao

We show that the cosmic microwave background (CMB) data of WMAP can give subelectronvolt limit on the neutrino mass: m_nu < 0.63 eV (95% CL). We also investigate its degeneracy with other cosmological parameters. In particular, we show the…

Astrophysics · Physics 2008-11-26 Kazuhide Ichikawa

It is important to explore the potential existence of lepton asymmetry in the neutrino sector. Conducting a joint analysis of DESI DR2 BAO data and \emph{Planck} 2018 CMB data, we obtain the upper limits on the neutrino degeneracy…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-17 Zhi-Chao Zhao , Dong-Mei Xia , Sai Wang

Cosmological parameter estimation exercises usually make the approximation that the three standard neutrinos have degenerate mass, which is at odds with recent terrestrial measurements of the difference in the square of neutrino masses. In…

Astrophysics · Physics 2009-11-11 Anze Slosar

We reanalyze the cosmological constraints on the existence of a net universal lepton asymmetry and neutrino degeneracy based upon the latest high resolution CMB sky maps from BOOMERANG, DASI, and MAXIMA-1. We generate likelihood functions…

Astrophysics · Physics 2009-11-07 M. Orito , T. Kajino , G. J. Mathews , Y. Wang

We examine the performance of the six-parameter $\Lambda$CDM model and its extensions in light of recent cosmological observations, with particular focus on neutrino properties inferred from cosmology. Using a broad suite of nine…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-12 Helena García Escudero , Kevork N. Abazajian

We present calculations showing that upcoming Cosmic Microwave Background (CMB) experiments will have the power to improve on current constraints on neutrino masses and provide new limits on neutrino degeneracy parameters. The latter could…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 M. Shimon , N. J. Miller , C. T. Kishimoto , C. J. Smith , G. M. Fuller , B. G. Keating

When combining cosmological and oscillations results to constrain the neutrino sector, the question of the propagation of systematic uncertainties is often raised. We address this issue in the context of the derivation of an upper bound on…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-25 F. Couchot , S. Henrot-Versillé , O. Perdereau , S. Plaszczynski , B. Rouillé d'Orfeuil , M. Spinelli , M. Tristram

The standard cosmological model, LCDM, provides an excellent fit to Cosmic Microwave Background (CMB) data. However, the model has well known problems. For example, the cosmological constant, is fine-tuned to 1 part in 10^100 and the cold…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 T. Shanks , R. W. F. Johnson , J. A. Schewtschenko , J. R. Whitbourn

Recent cosmic microwave background (CMB) results from BOOMERANG, MAXIMA, and DASI provide cosmological constraints on new physics that can be competitive with those derived from Big Bang Nucleosynthesis (BBN). In particular, both CMB and…

Astrophysics · Physics 2008-11-26 James P. Kneller , Robert J. Scherrer , Gary Steigman , Terry P. Walker

We present a precise analysis to test hypothetical models involving sterile neutrinos beyond the standard flat-$\Lambda$CDM cosmology with the CMB observations from the $Planck$ mission and BAO measurements. This analysis shows that adding…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-18 M. Ebadinejad
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