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We consider inhomogeneous big bang nucleosynthesis in light of the present observational situation. Different observations of He-4 and D disagree with each other, and depending on which set of observations one uses, the estimated primordial…

Astrophysics · Physics 2009-10-30 K. Kainulainen , H. Kurki-Suonio , E. Sihvola

Tsallis has suggested a nonextensive generalization of the Boltzmann-Gibbs entropy, the maximization of which gives a generalized canonical distribution under special constraints. In this brief report we show that the generalized canonical…

Statistical Mechanics · Physics 2021-04-28 Brian R. La Cour , William C. Schieve

Prediction of the primordial abundances of elements in the big-bang nucleosynthesis (BBN) is one of the three strong evidences for the big bang model. Precise knowledge of the baryon-to-photon ratio of the Universe from observations of the…

Nuclear Theory · Physics 2019-06-24 Vinay Singh , Joydev Lahiri , Debasis Bhowmick , D. N. Basu

The $f(Q)$ theories of modified gravity arise from the consideration of non-metricity as the basic geometric quantity, and have been proven to be very efficient in describing the late-time Universe. We use the Big Bang Nucleosynthesis (BBN)…

General Relativity and Quantum Cosmology · Physics 2023-02-08 Fotios K. Anagnostopoulos , Viktor Gakis , Emmanuel N. Saridakis , Spyros Basilakos

The general formalisms of the $q$-dual statistics, the Boltzmann-Gibbs statistics, and three versions of the Tsallis statistics known as Tsallis-1, Tsallis-2, and Tsallis-3 statistics have been considered in the canonical ensemble. We have…

Statistical Mechanics · Physics 2021-12-08 A. S. Parvan

The simplest, `standard' model of Big Bang Nucleosynthesis (SBBN) assumes three light neutrinos (N_nu = 3) and no significant electron neutrino asymmetry, leaving only one adjustable parameter: the baryon to photon ratio eta. The primordial…

Astrophysics · Physics 2009-11-10 James P. Kneller , Gary Steigman

Based on the Tsallis entropy, the nonextensive thermodynamic properties are studied as a q-deformation of classical statistical results using only probabilistic methods and straightforward calculations. It is shown that the constant in the…

Statistical Mechanics · Physics 2007-05-23 Franck Jedrzejewski

There exist a range of exciting scientific opportunities for Big Bang Nucleosynthesis (BBN) in the coming decade. BBN, a key particle astrophysics "tool" for decades, is poised to take on new capabilities to probe beyond standard model…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-23 Evan B. Grohs , J. Richard Bond , Ryan J. Cooke , George M. Fuller , Joel Meyers , Mark W. Paris

We derive constraints on the time variation of the Higgs vacuum expectation value $<\phi>$ through the effects on Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB). In the former case, we include the…

Astrophysics · Physics 2009-11-07 Jerry Jaiyul Yoo , Robert J. Scherrer

Based on a scenario of the inhomogeneous big-bang nucleosynthesis (IBBN), we investigate the detailed nucleosynthesis that includes the production of heavy elements beyond Li-7. From the observational constraints on light elements of He4…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-08 Riou Nakamura , Masa-aki Hashimoto , Shin-ichiro Fujimoto , Nobuya Nishimura , Katsuhiko Sato

We extend the model-independent likelihood analysis of big bang nucleosynthesis (BBN) based on He4 and Li7 to allow for numbers of degrees of freedom which differ from the standard model value characterized by $N_\nu = 3$. We use the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Keith A. Olive , David Thomas

We reconsider constraints on Brans-Dicke theories arising from the requirement of successful Big Bang Nucleosynthesis. Such constraints typically arise by imposing that the universe be radiation-dominated at early times, and therefore…

Astrophysics · Physics 2008-11-26 Antonio De Felice , Gianpiero Mangano , Pasquale D. Serpico , Mark Trodden

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

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 2007-05-23 Brian Fields , Subir Sarkar

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 address the emerging discrepancy between the Big Bang Nucleosynthesis data and standard cosmology, which asks for a bit longer evolution time. If this effect is real, one possible implication (in a framework of brane cosmology model) is…

High Energy Physics - Theory · Physics 2009-08-18 V. V. Flambaum , E. V. Shuryak

A study of the effects of non-extensivity on the modelling of atomic physics in hot dense plasmas is proposed within Tsallis' statistics. The electronic structure of the plasma is calculated through an average-atom model based on the…

Plasma Physics · Physics 2015-05-30 Jean-Christophe Pain , Denis Teychenné , Franck Gilleron

We present a model-independent reconstruction of the early expansion and thermal histories of the universe, obtained from light element abundance measurements. The expansion history is tightly constrained around the onset of the Big Bang…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-23 Rui An , Vera Gluscevic

The nonextensivity in a non-isothermal plasma system with the Coulombian long-range interactions is studied in the framework of Tsallis statistics. We present for first time a mathematical expression of the nonextensive parameter q based on…

Statistical Mechanics · Physics 2015-08-10 Jiulin Du

We study an effective relativistic mean-field model of nuclear matter with arbitrary proton fraction at finite temperature in the framework of nonextensive statistical mechanics, characterized by power-law quantum distributions. We…

Nuclear Theory · Physics 2015-06-16 A. Lavagno , D. Pigato
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