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From the observations of the anisotropies of the Cosmic Microwave Background (CMB) radiation, the WMAP satellite has provided a determination of the baryonic density of the Universe, \Omega_b.h^2, with an unprecedented precision. This…

Big Bang Nucleosynthesis provides us with an observational insight into the very early Universe. Since this mechanism of light element synthesis comes out of the standard model of particle cosmology which follows directly from General…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-14 Sai Swagat Mishra , Ameya Kolhatkar , P. K. Sahoo

We compute the big bang nucleosynthesis limit on the number of light neutrino degrees of freedom in a model-independent likelihood analysis based on the abundances of He4 and Li7. We use the two-dimensional likelihood functions to…

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

To constrain the universe before recombination (380000 years after the Big Bang), we mostly rely on the measurements of the primordial abundances that indicate the first insight into the thermal history of the universe. The first production…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-30 Tahani Makki , Mounib El Eid , Grant Mathews

We study the dynamics of the early universe in massive conformal gravity. In particular, we show that the theory is consistent with the observed values of the primordial abundances of light elements if we consider the existence of…

General Physics · Physics 2023-02-15 F. F. Faria

Primordial nucleosynthesis is a success story of the standard big bang (SBB) cosmology. We explore nucleosynthesis in possible models very different from SBB in which the cosmological scale factor increases linearly with time right through…

Nuclear Theory · Physics 2007-05-23 Daksh Lohiya , Annu Batra , Shobhit Mahajan , Amitabha Mukherjee

Observations made using large ground-based and space-borne telescopes have probed cosmic history all the way from the present-day to a time when the Universe was less than a tenth of its present age. Earlier on lies the remaining frontier,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Volker Bromm , Naoki Yoshida , Lars Hernquist , Christopher F. McKee

Primordial molecules were formed during the Dark Ages, i.e. the time between recombination and reionization in the early Universe. The purpose of this article is to analyze the formation of primordial molecules based on heavy elements…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 P. Vonlanthen , T. Rauscher , C. Winteler , D. Puy , M. Signore , V. Dubrovich

We update the Big Bang Nucleosynthesis calculations on the basis of the recent NACRE compilation. The average values of the calculated abundances of light nuclei do not differ significantly from that obtained using the previous Fowler's…

Astrophysics · Physics 2016-08-30 Elisabeth Vangioni-Flam , Alain Coc , Michel Casse

We summarize some applications of big bang nucleosythesis (BBN) and the cosmic microwave background (CMB) to constrain the first moments of the creation of matter in the universe. We review the basic elements of BBN and how it constraints…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-23 Grant. J. Mathews , Mayukh Gangopadhyay , Nishanth Sasankan , Kiyotomo Ichiki , Toshitaka Kajino

We take a fresh look at the limits on the number of neutrino flavors derived from big bang nucleosynthesis. In particular, recent measurements of the \he4 abundance enable one to estimate the primordial \he4 mass fraction at $Y_p = 0.232…

High Energy Physics - Phenomenology · Physics 2016-09-01 Keith A. Olive , Gary Steigman

According to the standard models of particle physics and cosmology, there should be a background of cosmic neutrinos in the present Universe, similar to the cosmic microwave photon background. The weakness of the weak interactions renders…

High Energy Physics - Phenomenology · Physics 2013-05-27 Gary Steigman

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 have performed new Big Bang Nucleosynthesis calculations which employ arbitrarily-specified, time-dependent neutrino and antineutrino distribution functions for each of up to four neutrino flavors. We self-consistently couple these…

Astrophysics · Physics 2010-04-30 Christel J. Smith , George M. Fuller , Michael S. Smith

The discrepancy between the theoretical prediction of primordial lithium abundances and astronomical observations is called the Lithium Problem. We find that extra contributions from non-thermal hydrogen and helium during Big Bang…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-31 Ming-Ming Kang , Yang Hu , Hong-Bo Hu , Shou-Hua Zhu

The heavy elements formed by neutron capture processes have an interesting history from which we can extract useful clues to and constraints upon both the characteristics of the processes themselves and the star formation and…

Astrophysics · Physics 2009-11-07 J. W. Truran , J. J. Cowan , C. A. Pilachowski , C. Sneden

Light element nucleosynthesis is an important chapter of nuclear astrophysics. Specifically, the rare and fragile light nuclei Lithium, Beryllium and Boron (LiBeB) are not generated in the normal course of stellar nucleosynthesis (except…

Astrophysics · Physics 2009-10-31 Elisabeth Vangioni-Flam , Michel Casse

The study of particle creation phenomena at the expense of the gravitational field is of great research interest. It might solve the cosmological puzzle single-handedly, without the need for either dark energy or the modified theory of…

General Relativity and Quantum Cosmology · Physics 2018-06-26 Abhik Kumar Sanyal , Subhra Debnath

The most energetic part of the electromagnetic spectrum bears the purest clues to the synthesis of atomic nuclei in the universe. The decay of radioactive species, synthesized in stellar environments and ejected into the interstellar…

Astrophysics · Physics 2009-10-31 Elisabeth Vangioni-Flam , Reuven Ramaty , Michel Casse

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