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Related papers: Early-universe constraints on the electron mass

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Coherent forward scattering processes by neutrino-scalar nonstandard interactions (SNSI) induce an effective neutrino mass. In the Early Universe, a large neutrino effective mass restricts the production of neutrinos. The SNSI effect is…

High Energy Physics - Phenomenology · Physics 2021-02-26 Jorge Venzor , Abdel Pérez-Lorenzana , Josue De-Santiago

We investigate how sterile neutrinos with a range of masses influence cosmology in MeV-scale reheating temperature scenarios. By computing the production of sterile neutrinos through the combination of mixing and scattering in the early…

High Energy Physics - Phenomenology · Physics 2020-08-13 Takuya Hasegawa , Nagisa Hiroshima , Kazunori Kohri , Rasmus S. L. Hansen , Thomas Tram , Steen Hannestad

By numerically solving the quantum kinetic equations we compute the range of parameters where the $\nu_\mu \to \nu_s$ oscillation solution to the atmospheric neutrino anomaly is consistent with a stringent big bang nucleosynthesis (BBN)…

High Energy Physics - Phenomenology · Physics 2008-11-26 R. Foot

In this thesis, we focus on the study of the variation of the electron mass $m_e$, and the fine structure constant $\alpha$, at different cosmic times. We analyze the details of the recombination physics, including helium recombination, in…

Cosmology and Nongalactic Astrophysics · Physics 2009-06-02 Claudia G. Scóccola

A critical review is given of the current status of cosmological nucleosynthesis. In the framework of the Standard Model with 3 types of relativistic neutrinos, the baryon-to-photon ratio, $\eta$, corresponding to the inferred primordial…

Astrophysics · Physics 2011-02-09 Brian Fields , Subir Sarkar

In this study we present a comprehensive sensitivity atlas for Big Bang Nucleosynthesis (BBN) in which we quantify the dependence of the primordial abundances of helium-4, deuterium, and lithium-7 as well as $N_{\rm{eff}}$ on variations in…

High Energy Physics - Phenomenology · Physics 2026-03-25 Anne-Katherine Burns

We revisit the upper limits on the abundance of unstable massive relic particles provided by the success of Big-Bang Nucleosynthesis calculations. We use the cosmic microwave background data to constrain the baryon-to-photon ratio, and…

Astrophysics · Physics 2009-09-11 Richard H. Cyburt , John Ellis , Brian D. Fields , Keith A. Olive

We present robust, model-marginalized limits on both the total neutrino mass ($\sum m_\nu$) and abundance ($N_{\rm eff}$) to minimize the role of parameterizations, priors and models when extracting neutrino properties from cosmology. The…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-14 Eleonora di Valentino , Stefano Gariazzo , Olga Mena

A range of experimental results point to the existence of a massive neutrino. The recent high precision measurements of the cosmic microwave background and the large scale surveys of galaxies can be used to place an upper bound on this…

Astrophysics · Physics 2009-06-12 C. Zunckel , P. G Ferreira

We consider the effect on Big Bang Nucleosynthesis (BBN) of new measurements of the $d(p,\gamma){}^3$He cross section by the LUNA Collaboration. These have an important effect on the primordial abundance of D/H which is also sensitive to…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-23 Tsung-Han Yeh , Keith A. Olive , Brian D. Fields

In Poulin and Serpico [Phys. Rev. Lett. 114, 091101 (2015)] we have recently argued that when the energy of a photon injected in the primordial plasma falls below the pair-production threshold, the universality of the non-thermal photon…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-01 Vivian Poulin , Pasquale Dario Serpico

We reexamine big bang nucleosynthesis with large-scale baryon density inhomogeneities when the length scale of the density fluctuations exceeds the neutron diffusion length ($\sim 10^7-10^8$ cm at BBN), and the amplitude of the fluctuations…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-12 John D. Barrow , Robert J. Scherrer

We reanalyze the cosmological constraints on the existence of a net universal lepton asymmetry and neutrino degeneracy. We show that neutrinos can begin to decouple at higher temperatures than previous estimates due to several corrections…

Astrophysics · Physics 2007-05-23 M. Orito , T. Kajino , G. J. Mathews , R. N. Boyd

The expansion history and thermal physical process that happened in the early Universe before big bang nucleosynthesis (BBN) remains relatively unconstrained by observations. Low reheating temperature universes with normalcy temperatures of…

High Energy Physics - Phenomenology · Physics 2023-12-07 Kevork N. Abazajian , Helena García Escudero

The R\'{e}nyi entropy, a one-parameter generalization of Boltzmann-Gibbs entropy, offers a promising framework for probing quantum gravitational effects in cosmology. By modifying the entropy-area relation of the apparent horizon, R\'{e}nyi…

General Physics · Physics 2025-07-22 Ahmad Sheykhi , Ava Shahbazi Sooraki

We use Big Bang Nucleosynthesis calculations and light element abundance data to constrain the relative variation of the deuteron binding energy since the universe was a few minutes old, $\delta Q = Q(BBN)-Q(present)$. Two approaches are…

Astrophysics · Physics 2009-08-18 V. F. Dmitriev , V. V. Flambaum , J. K. Webb

We analyze the effect of a variation of the strange nucleon matrix element $\langle N| m_s \bar{s}s|N\rangle$ on the abundances of the light elements produced in the Big Bang. For that, we vary the nucleon mass in the leading eight…

High Energy Physics - Phenomenology · Physics 2025-02-24 Ulf-G. Meißner , Bernard Metsch , Helen Meyer

We study the implications of precision measurements of light-element abundances, in combination with the Cosmic Microwave Background, for scenarios of physics beyond the Standard Model that generate large inhomogeneities in the…

High Energy Physics - Phenomenology · Physics 2025-09-12 Hengameh Bagherian , Majid Ekhterachian , Stefan Stelzl

We consider the equilibration of the 'wrong--helicity' Dirac neutrino states $\nu_{+}$ and $\overline\nu_{-}$ in the early Universe via weak interactions and calculate carefully the thermally averaged production rate, taking into account…

High Energy Physics - Phenomenology · Physics 2008-11-26 K. Enqvist , H. Uibo

Comparing the latest observed abundances of 4He and D, we make a ?2 analysis to see whether it is possible to reconcile primordial nucleosynthesis using up-to-date nuclear data of NACRE II and the mean-life of neutrons. If we adopt the…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-05 R. Ichimasa , R. Nakamura , M. Hashimoto , K. Arai