scholarly journals The status of Big Bang nucleosynthesis in July 1988

1989 ◽  
Vol 8 ◽  
pp. 693-696
Author(s):  
Hubert Reeves
Keyword(s):  
Phase Transition ◽  
Big Bang ◽  
Theoretical Ground ◽  
Big Bang Nucleosynthesis ◽  
Primordial Nucleosynthesis ◽  
Hadron Phase ◽  
The Status ◽  
Primordial Abundance ◽  
Bona Fide ◽  
Made In

Important progresses have been made in two fronts in the few past years.On the theoretical ground, we have realized the importance of the quark-hadron phase transition as possibly influencing in a major way the yields of die primordial nucleosynthesis isotopes.On the observational ground, the status of lithium as a bona-fide cosmological observable has been confirmed and its primordial abundance can be evaluated with increased confidence.

scholarly journals Lithium-6 Nucleosynthesis in the ISM

1995 ◽  
Vol 10 ◽  
pp. 465-466
Author(s):  
Robert A. Malaney
Keyword(s):  
Big Bang ◽  
Galactic Evolution ◽  
Local Interstellar Medium ◽  
Complete Understanding ◽  
Big Bang Nucleosynthesis ◽  
Lithium Isotopes ◽  
Primordial Nucleosynthesis ◽  
The Past ◽  
The Galaxy ◽  
Primordial Abundance

The nucleosynthesis of 6Li in the galaxy has become of considerable interest in the past year. This is largely because of the exciting developments relating to the first detection of this isotope outside of our own solar system. Not only has 6Li been recently detected in the atmospheres of halo dwarfs [1-2], but also in the local interstellar medium (ISM) [3-4].It is well known that knowledge of the primordial abundance of the lithium isotopes has important ramifications for cosmology, through the constraints they impose on standard big bang nucleosynthesis (SBBN) [5], and those imposed on non-standard primordial nucleosynthesis models. Since a complete understanding of the galactic evolution of the lithium isotopes is a prerequisite to unambiguously determining their primordial abundance, a thorough interpretation of the new 6Li data in the context of chemical evolution models cannot be overstated.

CP violating vacuum transition and Big Bang Nucleosynthesis

2005 ◽  
Vol 201 ◽  
pp. 451-452
Author(s):  
H. L. Duorah ◽  
R. K. Das
Keyword(s):  
Transition Temperature ◽  
Early Universe ◽  
Chemical Potential ◽  
Big Bang ◽  
Helium Abundance ◽  
Big Bang Nucleosynthesis ◽  
Primordial Nucleosynthesis ◽  
The Universe ◽  
Limiting Value ◽  
Made In

An analysis of primordial nucleosynthesis is made in the perspective of transition in the early universe from quark gluon to a hadronic phase in a CP violating vacuum. The universe opaque to color, quarks and anti quarks binds into globally colorless hadrons. u, d and s quarks are considered in a sea of degenerate neutrinos for the case of μve = μvμ = μvτ. The nn/np ratio is calculated for a transition temperature ˜ 100 − 200MeV for various values of neutrino degeneracy ξve = μve/T, μve being the chemical potential of electron type neutrino. The limiting value of ξve is found to be 2.38, if the upper bound of fractional helium abundance Yp is 0.26.

scholarly journals NEUTRINO SPECTRUM DISTORTION DUE TO OSCILLATIONS AND ITS BBN EFFECT

2004 ◽  
Vol 13 (05) ◽  
pp. 831-841 ◽  
Author(s):  
DANIELA KIRILOVA
Keyword(s):  
Sterile Neutrino ◽  
Big Bang ◽  
Neutrino Energy ◽  
Electron Neutrino ◽  
Initial Population ◽  
Neutrino Mixing ◽  
Big Bang Nucleosynthesis ◽  
Cosmological Constraints ◽  
Neutrino Spectrum ◽  
Primordial Abundance

We study the distortion of electron neutrino energy spectrum due to oscillations with the sterile neutrino νe↔νs, for different initial populations of the sterile state δNs at the onset of oscillations. The influence of this spectrum distortion on Big Bang Nucleosynthesis is analyzed. Only the case of an initially empty sterile state was studied in previous publications. The primordial abundance of 4He is calculated for all possible δNs:0≤δNs≤1 in the model of oscillations, effective after electron neutrino decoupling, for which the spectrum distortion effects on the neutron–proton transitions are the strongest. It is found that the spectrum distortion effect may be dominant, not only in the case of small δNs, but also in the case of large initial population of νs. For example, in the resonant case it may play a considerable role even for very large δNs~0.8. Cosmological constraints on neutrino mixing for small δNs are discussed.

scholarly journals THE STATUS OF NEUTRINO MASS

1998 ◽  
Vol 13 (25) ◽  
pp. 4409-4423 ◽  
Author(s):  
DAVID O. CALDWELL
Keyword(s):  
Dark Matter ◽  
Neutrino Mass ◽  
Heavy Element ◽  
Sterile Neutrino ◽  
Big Bang ◽  
Atmospheric Neutrinos ◽  
Big Bang Nucleosynthesis ◽  
Robust Solution ◽  
The Status ◽  
Mass Pattern

New experimental results, if correct, require at least one light sterile neutrino, in addition to the three active ones, to accommodate the mass differences required to explain the solar νe deficit, the anomalous μ/e ratio produced by atmospheric neutrinos, and either the candidate events for νμ→ νe (or [Formula: see text]) from the LSND experiment, or the possible need for a hot component of dark matter. This neutrino mass pattern can not only accommodate all these four requirements, but also provide a robust solution to a problem presently making heavy-element synthesis by supernovae impossible and resolve a possible discrepancy between big bang nucleosynthesis theory and observations.

scholarly journals Gravitational Waves from the Cosmological Quark-Hadron Phase Transition Revisited

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 304
Author(s):  
Pauline Lerambert-Potin ◽  
José Antonio de Freitas Pacheco
Keyword(s):  
Phase Transition ◽  
Gravitational Wave ◽  
Equations Of State ◽  
Wave Spectrum ◽  
Gluon Plasma ◽  
Big Bang ◽  
Einstein Equations ◽  
Black Hole Binaries ◽  
Hadron Phase ◽  
Gravitational Wave Background

The recent claim by the NANOGrav collaboration of a possible detection of an isotropic gravitational wave background stimulated a series of investigations searching for the origin of such a signal. The QCD phase transition appears as a natural candidate and in this paper the gravitational spectrum generated during the conversion of quarks into hadrons is calculated. Here, contrary to recent studies, equations of state for the quark-gluon plasma issued from the lattice approach were adopted. The duration of the transition, an important parameter affecting the amplitude of the gravitational wave spectrum, was estimated self-consistently with the dynamics of the universe controlled by the Einstein equations. The gravitational signal generated during the transition peaks around 0.28 μHz with amplitude of h02Ωgw≈7.6×10−11, being unable to explain the claimed NANOGrav signal. However, the expected QCD gravitational wave background could be detected by the planned spatial interferometer Big Bang Observer in its advanced version for frequencies above 1.0 mHz. This possible detection assumes that algorithms recently proposed will be able to disentangle the cosmological signal from that expected for the astrophysical background generated by black hole binaries.

scholarly journals A new tension in the cosmological model from primordial deuterium?

2021 ◽  
Vol 502 (2) ◽  
pp. 2474-2481
Author(s):  
Cyril Pitrou ◽  
Alain Coc ◽  
Jean-Philippe Uzan ◽  
Elisabeth Vangioni
Keyword(s):  
Big Bang ◽  
Reaction Cross ◽  
Light Elements ◽  
Neutron Lifetime ◽  
Microwave Background ◽  
Big Bang Nucleosynthesis ◽  
Baryonic Density ◽  
The Status ◽  
Big Bang Model ◽  
The Big Bang

ABSTRACT Recent measurements of the D(p,γ)3He nuclear reaction cross-section and of the neutron lifetime, along with the reevaluation of the cosmological baryon abundance from cosmic microwave background (CMB) analysis, call for an update of abundance predictions for light elements produced during the big-bang nucleosynthesis (BBN). While considered as a pillar of the hot big-bang model in its early days, BBN constraining power mostly rests on deuterium abundance. We point out a new ≃1.8σ tension on the baryonic density, or equivalently on the D/H abundance, between the value inferred on one hand from the analysis of the primordial abundances of light elements and, on the other hand, from the combination of CMB and baryonic oscillation data. This draws the attention on this sector of the theory and gives us the opportunity to reevaluate the status of BBN in the context of precision cosmology. Finally, this paper presents an upgrade of the BBN code primat.

scholarly journals Primordial Nucleosynthesis For The New Millennium

2000 ◽  
Vol 198 ◽  
pp. 13-24
Author(s):  
G. Steigman
Keyword(s):  
Standard Model ◽  
Early Universe ◽  
Particle Physics ◽  
Nuclear Reactor ◽  
Big Bang ◽  
Status Report ◽  
Primordial Nucleosynthesis ◽  
The Road ◽  
The Standard Model ◽  
Primordial Abundance

The physics of the standard hot big bang cosmology ensures that the early Universe was a primordial nuclear reactor, synthesizing the light nuclides (D, 3He, 4He, and 7Li) in the first 20 minutes of its evolution. After an overview of nucleosynthesis in the standard model (SBBN), the primordial abundance yields will be presented, followed by a status report (intended to stimulate further discussion during this symposium) on the progress along the road from observational data to inferred primordial abundances. Theory will be confronted with observations to assess the consistency of SBBN and to constrain cosmology and particle physics. Some of the issues/problems key to SBBN in the new millenium will be highlighted, along with a wish list to challenge theorists and observers alike.

Sign in / Sign up

Export Citation Format

Share Document