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Related papers: Finding eV-scale Light Relics with Cosmological Ob…

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Thermal relics lighter than an MeV contribute to the energy density of the universe at the time of nucleosynthesis and recombination. Constraints on extra radiation degrees of freedom typically exclude even the simplest of such dark…

High Energy Physics - Phenomenology · Physics 2019-05-29 Asher Berlin , Nikita Blinov

The recent discovery of B-modes in the polarization pattern of the Cosmic Microwave Background by the BICEP2 experiment has important implications for neutrino physics. We revisit cosmological bounds on light sterile neutrinos and show that…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-17 Maria Archidiacono , Nicolao Fornengo , Stefano Gariazzo , Carlo Giunti , Steen Hannestad , Marco Laveder

In the presented work we consider the influence of a hypothetical sterile neutrino (with eV-scale mass) on the determination of cosmological parameters. If it is detected, it will be necessary to include it into the $\Lambda \rm CDM$ model…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-13 P. A. Chernikov , A. V. Ivanchik

We consider the inference of the cosmic radiation density, traditionally parameterised as the effective number of neutrino species N_eff, from precision cosmological data. Paying particular attention to systematic effects, notably…

Astrophysics · Physics 2008-11-26 Jan Hamann , Steen Hannestad , Georg G. Raffelt , Yvonne Y. Y. Wong

We consider the possibility that a large fraction of the ultrahigh energy cosmic rays are decay products of Z bosons which were produced in the scattering of ultrahigh energy cosmic neutrinos on cosmological relic neutrinos. We compare the…

High Energy Physics - Phenomenology · Physics 2009-11-07 Z. Fodor , S. D. Katz , A. Ringwald

We have derived new bounds on the relativistic energy density in the Universe from cosmic microwave background (CMB), large scale structure (LSS), and type Ia supernova (SNI-a) observations. In terms of the effective number of neutrino…

Astrophysics · Physics 2009-11-13 Steen Hannestad

The Short BaseLine (SBL) neutrino oscillations anomalies hint at the presence of a sterile neutrino with a mass of around 1 eV. However, such neutrino is highly incompatible with the cosmological data, in particular from the Cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-17 Stefano Gariazzo

The case for small neutrino mass differences from atmospheric and solar neutrino oscillation experiments has become compelling, but leaves the overall neutrino mass scale m_nu undetermined. The most restrictive limit of m_nu < 0.8 eV arises…

Astrophysics · Physics 2009-11-07 G. G. Raffelt

A quintessence scalar field or cosmon interacting with neutrinos can have important effects on cosmological structure formation. Within growing neutrino models the coupling becomes effective only in recent times, when neutrinos become…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-29 Nico Wintergerst , Valeria Pettorino , David F. Mota , Christof Wetterich

New particles in theories beyond the standard model can manifest as stable relics that interact strongly with visible matter and make up a small fraction of the total dark matter abundance. Such particles represent an interesting physics…

High Energy Physics - Phenomenology · Physics 2023-07-10 David McKeen , David E. Morrissey , Maxim Pospelov , Harikrishnan Ramani , Anupam Ray

Working within the framework of the minimal supergravity model with gauge coupling unification and radiative electroweak symmetry breaking, we evaluate the cosmological relic density from lightest neutralinos produced in the early universe.…

High Energy Physics - Phenomenology · Physics 2008-11-26 Howard Baer , Michal Brhlik

We derive constraints on the relic abundance of a generic particle of mass $\sim~1-10^{14}$ TeV which decays into neutrinos at cosmological epochs, using data from the Fr\'ejus and IMB nucleon decay detectors and the Fly's Eye air shower…

High Energy Physics - Phenomenology · Physics 2011-02-16 P. Gondolo , G. Gelmini , S. Sarkar

We show that galaxy redshift surveys sensitively probe the neutrino mass, with eV mass neutrinos suppressing power by a factor of two. The Sloan Digital Sky Survey can potentially detect $N$ nearly degenerate massive neutrino species with…

Astrophysics · Physics 2009-10-07 Wayne Hu , Daniel J. Eisenstein , Max Tegmark

The light relic density affects the thermal and expansion history of the early Universe leaving a number of observable imprints. We focus on the primordial abundances of light elements produced during the process of Big Bang nucleosynthesis…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-19 Alex Laguë , Joel Meyers

Cosmological observations are becoming increasingly sensitive to the effects of light particles in the form of dark radiation (DR) at the time of recombination. The conventional observable of effective neutrino number, $N_{\rm eff}$, is…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-30 Christopher Brust , Yanou Cui , Kris Sigurdson

Light sterile neutrinos with a mass around 1 eV have been studied for many years as a possible explanation of the so called short-baseline neutrino oscillation anomalies. Recently, several neutrino oscillation experiments reported…

High Energy Physics - Phenomenology · Physics 2020-02-19 S. Gariazzo

Cosmological measurements over the next decade will enable us to shed light on the content and evolution of the Universe. Complementary measurements of the Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations are expected to…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-10 Siddharth Mishra-Sharma , David Alonso , Joanna Dunkley

A larger Planck scale during an early epoch leads to a smaller Hubble rate, which is the measure for efficiency of primordial processes. The resulting slower cosmic tempo can accommodate alternative cosmological histories. We consider this…

High Energy Physics - Phenomenology · Physics 2023-12-15 Hooman Davoudiasl , Matthew Sullivan

We forecast the sensitivity of thirty-five different combinations of future Cosmic Microwave Background and Large Scale Structure data sets to cosmological parameters and to the total neutrino mass. We work under conservative assumptions…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-08 Thejs Brinckmann , Deanna C. Hooper , Maria Archidiacono , Julien Lesgourgues , Tim Sprenger

The MiniBooNE collaboration recently released a report claiming have observed an excess of electron and anti-electron neutrino with significance of $4.8 \, \sigma$ C.L. corroborating, in this way, the long-standing LSND anomaly. Combined…

High Energy Physics - Phenomenology · Physics 2019-08-27 C. A. de S. Pires