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Heavy Neutral Leptons (HNLs) are strongly motivated by theory due to their capability of simultaneously explaining the observed phenomena of dark matter, neutrino oscillations and the baryon asymmetry of the Universe. The existence of such…

High Energy Physics - Phenomenology · Physics 2020-12-09 Nashwan Sabti , Andrii Magalich , Anastasiia Filimonova

We reanalyze the effect of magnetic fields in BBN, incorporating several features which were omitted in previous analyses. We find that the effects of coherent magnetic fields on the weak interaction rates and the electron thermodynamic…

Astrophysics · Physics 2014-10-13 Peter. J. Kernan , Glenn D. Starkman , Tammay Vachaspati

We study the early evolution of the electron fraction (or, alternatively, the neutron-to-proton ratio) in the region above the hot proto-neutron star formed after a supernova explosion. We study the way in which the electron fraction in…

Astrophysics · Physics 2009-10-30 G. C. McLaughlin , G. M. Fuller , J. R. Wilson

A brief overview of non-standard big bang nucleosynthesis (BBN) scenarios is presented. Trends and results of the light-element nucleosynthesis in BBN scenarios with small-scale or large-scale inhomogeneity, the presence of antimatter…

Astrophysics · Physics 2007-05-23 Karsten Jedamzik

The thermal rates for converting neutrons to protons, and vice versa, are calculated, including corrections of order 1 MeV divided by a nucleon mass. The results imply that the primodial helium abundance predicted for big bang…

High Energy Physics - Phenomenology · Physics 2009-09-25 David Seckel

Relativistic energy density functionals have become a standard framework for nuclear structure studies of ground-state properties and collective excitations over the entire nuclide chart. We review recent developments in modeling nuclear…

Nuclear Theory · Physics 2015-10-28 N. Paar , T. Marketin , D. Vale , D. Vretenar

We calculate the effect of variation in the light-current quark mass, $m_q$, on standard big bang nucleosynthesis. A change in $m_q$ at during the era of nucleosynthesis affects nuclear reaction rates, and hence primordial abundances, via…

Nuclear Theory · Physics 2010-01-15 J. C. Berengut , V. F. Dmitriev , V. V. Flambaum

We study big bang nucleosynthesis in the presence of large mass-scale, non-linear entropy fluctuations. Overdense regions, with masses above the local baryon-Jeans mass, are expected to collapse and form condensed objects. Surviving…

Astrophysics · Physics 2009-10-22 K. Jedamzik , G. M. Fuller

We assess the effects on Big Bang Nucleosynthesis (BBN) of lepton number generation in the early universe resulting from the two-doublet four-neutrino mass/mixing scheme. It has been argued that this neutrino mass/mixing arrangement gives…

Astrophysics · Physics 2009-10-31 Kevork Abazajian , George M. Fuller , Xiangdong Shi

Employing the weak interaction reaction wherein a heavy electron is captured by a proton to produce a neutron and a neutrino, the neutron production rate for neutral hydrogen gases and for fully ionized plasmas is computed. Using the…

High Energy Physics - Phenomenology · Physics 2013-05-22 A. Widom , J. Swain , Y. N. Srivastava

Unexplained variations of the decay rate for weak interaction decays such as $\beta^{\pm}$-decay, electron capture, as well as strong interaction $\alpha$-decay have been reported. Some researcher interpreted these variations as caused by…

Nuclear Experiment · Physics 2022-04-27 Shih-Chieh Liu , David Koltick , Haoyu Wang , Jonathan Nistor , Jordan Heim , Thomas Ward

The neutron beta-decay lifetime plays an important role both in understanding weak interactions within the framework of the Standard Model and in theoretical predictions of the primordial abundance of 4He in Big Bang Nucleosynthesis. In…

Based on large-scale shell model calculations we have determined the electron capture, positron capture and beta-decay rates on more than 100 nuclei in the mass range A=45-65. The rates are given for densities \rho Y_e =10^7-10^{10}…

Nuclear Theory · Physics 2011-05-05 K. Langanke , G. Martinez-Pinedo

A new accurate evaluation of primordial light nuclei abundances is presented. The proton to neutron conversion rates have been corrected to take into account radiative effects, finite nucleon mass, thermal and plasma corrections. The…

Astrophysics · Physics 2009-10-31 S. Esposito , G. Mangano , G. Miele , O. Pisanti

We identify a new, flux-dependent correction to the antineutrino spectrum as produced in nuclear reactors. The abundance of certain nuclides, whose decay chains produce antineutrinos above the threshold for inverse beta decay, has a…

High Energy Physics - Phenomenology · Physics 2016-03-30 Patrick Huber , Patrick Jaffke

Recently it is reported that there is the discrepancy between big bang nucleosynthesis theory and observations (BBN crisis). We show that BBN predictions agree with the primordial abundances of light elements, He4, D, He3 and Li7 inferred…

Astrophysics · Physics 2008-11-26 K. Kohri , M. Kawasaki , Katsuhiko Sato

The term dark radiation is used both to describe a noninteracting neutrino species and as a correction to the Friedmann Equation in the simplest five-dimensional RS-II brane-world cosmology. In this paper we consider the constraints on both…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-04 Nishanth Sasankan , Mayukh. R. Gangopadhyay , Grant. J. Mathews , Motohiko Kusakabe

Scalar dark matter can interact with Standard Model (SM) particles, altering the fundamental constants of Nature in the process. Changes in the fundamental constants during and prior to Big Bang nucleosynthesis (BBN) produce changes in the…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-14 Y. V. Stadnik , V. V. Flambaum

We consider the effects on big bang nucleosynthesis (BBN) of the radiative decay of a long-lived massive particle. If high-energy photons are emitted after the BBN epoch ($t \sim 1 - 10^3$ sec), they may change the abundances of the light…

High Energy Physics - Phenomenology · Physics 2011-05-05 M. Kawasaki , K. Kohri , Takeo Moroi

We examine the possibility that Big Bang Nucleosynthesis (BBN) may produce non-trivial amounts of $^6$Li. If a primordial component of this isotope could be observed, it would provide a new fundamental test of Big-Bang cosmology, as well as…

Astrophysics · Physics 2008-11-26 Kenneth M. Nollett , Martin Lemoine , David N. Schramm