Big Bang nucleosynthesis, microwave anisotropy, and the light element abundances

2005 ◽  
Vol 752 ◽  
pp. 522-531 ◽  
Author(s):  
A. Coc ◽  
C. Angulo ◽  
E. Vangioni-Flam ◽  
P. Descouvemont ◽  
A. Adahchour
Keyword(s):  
Light Element ◽  
Big Bang ◽  
Big Bang Nucleosynthesis ◽  
Element Abundances

scholarly journals Progress on the BL2 beam measurement of the neutron lifetime

2019 ◽  
Vol 219 ◽  
pp. 03002 ◽  
Author(s):  
Shannon F. Hoogerheide ◽  
Jimmy Caylor ◽  
Evan R. Adamek ◽  
Eamon S. Anderson ◽  
Ripan Biswas ◽  
...  
Keyword(s):  
Light Element ◽  
Big Bang ◽  
Neutron Lifetime ◽  
Big Bang Nucleosynthesis ◽  
Element Abundances ◽  
Cold Neutron Beam ◽  
The Standard Model ◽  
Systematic Effects ◽  
Mixing Matrix ◽  
Beam Technique

A precise value of the neutron lifetime is important in several areas of physics, including determinations of the quark-mixing matrix element |Vud|, related tests of the Standard Model, and predictions of light element abundances in Big Bang Nucleosynthesis models. We report the progress on a new measurement of the neutron lifetime utilizing the cold neutron beam technique. Several experimental improvements in both neutron and proton counting that have been developed over the last decade are presented. This new effort should yield a final uncertainty on the lifetime of 1 s with an improved understanding of the systematic effects.

Signature of Long-lived Relic Particles on Primordial Light Element Abundances in Big Bang Nucleosynthesis

2010 ◽  
Author(s):  
Motohiko Kusakabe ◽  
Toshitaka Kajino ◽  
Takashi Yoshida ◽  
Grant J. Mathews ◽  
Isao Tanihara ◽  
...  
Keyword(s):  
Light Element ◽  
Big Bang ◽  
Big Bang Nucleosynthesis ◽  
Element Abundances

POSSIBILITY OF A SIGNATURE OF THE RADIATIVE DECAY OF RELIC PARTICLES ON LIGHT ELEMENT ABUNDANCES

2007 ◽  
Vol 22 (25n28) ◽  
pp. 2019-2026
Author(s):  
MOTOHIKO KUSAKABE ◽  
TOSHITAKA KAJINO ◽  
GRANT J. MATHEWS
Keyword(s):  
Radiative Decay ◽  
Light Element ◽  
Big Bang ◽  
Decay Process ◽  
Big Bang Nucleosynthesis ◽  
Element Abundances ◽  
Unstable Particles ◽  
Halo Stars ◽  
Primordial Abundance ◽  
Isotopic Abundances

Recent spectroscopic observations of metal poor stars have indicated that both 7 Li and 6 Li have abundance plateaus as a function of the metallicity. Abundances of 7 Li are about a factor three lower than the primordial abundance predicted by standard big-bang nucleosynthesis (SBBN), and 6 Li abundances are ~ 1/20 of 7 Li , whereas SBBN predicts negligible amounts of 6 Li compared to the detected level. These discrepancies suggest that 6 Li has another cosmological or Galactic origin. Furthermore, it appear that 7 Li (and also 6 Li ) has been depleted from its primordial abundance by some post-BBN processes. We study the possibility that the radiative decay of long-lived particles has affected the cosmological lithium abundances in reality. We calculate the non-thermal nucleosynthesis associated with the radiative decay, and explore the allowed region of the parameters specifying the properties of long-lived particles. We also impose constraints from observations of the CMB energy spectrum. It is found that non-thermal nucleosynthesis could produces 6 Li at the level detected in metal poor halo stars (MPHSs), when the lifetime of the unstable particles is of the order ~ 108 − 1012 s depending on their initial abundance. We conclude that a combination of two different processes could explain the lithium isotopic abundances in MPHSs. First, a non-thermal cosmological nucleosynthesis associated with the radiative decay of unstable particles; and second, about the same degree of stellar depletion of both primordial lithium isotopic abundances. If MPHSs experience 6 Li depletion of factor much greater than ~ 3, the simple radiative decay process can not be the cause of large 6 Li abundances in MPHSs.

BIG BANG NUCLEOSYNTHESIS: AN UPDATE

1996 ◽  
Vol 11 (03) ◽  
pp. 409-428 ◽  
Author(s):  
KEITH A. OLIVE ◽  
SEAN T. SCULLY
Keyword(s):  
Standard Model ◽  
Light Element ◽  
Big Bang ◽  
Current Status ◽  
Beyond The Standard Model ◽  
Effective Number ◽  
Big Bang Nucleosynthesis ◽  
Element Abundances ◽  
The Standard Model

The current status of big bang nucleosynthesis is reviewed with an emphasis on the comparison between the observational determination of the light element abundances of D , 3 He , 4 He and 7 Li and the predictions from theory. In particular, we present new analyses for 4 He and 7 Li . Implications for physics beyond the standard model are also discussed. In addition, limits on the effective number of neutrino flavors are updated.

scholarly journals Big Bang nucleosynthesis with long-lived strongly interacting relic particles

2009 ◽  
Vol 5 (S268) ◽  
pp. 33-38
Author(s):  
Motohiko Kusakabe ◽  
Toshitaka Kajino ◽  
Takashi Yoshida ◽  
Grant J. Mathews
Keyword(s):  
Beta Decay ◽  
Bound States ◽  
Nuclear Reactions ◽  
Interaction Strength ◽  
Light Element ◽  
Big Bang ◽  
Heavy Elements ◽  
Big Bang Nucleosynthesis ◽  
Element Abundances ◽  
Strongly Interacting

AbstractWe study effects of relic long-lived strongly interacting massive particles (X particles) on big bang nucleosynthesis (BBN). The X particle is assumed to have existed during the BBN epoch, but decayed long before detected. The interaction strength between an X and a nucleon is assumed to be similar to that between nucleons. Rates of nuclear reactions and beta decay of X-nuclei are calculated, and the BBN in the presence of neutral charged X0 particles is calculated taking account of captures of X0 by nuclei. As a result, the X0 particles form bound states with normal nuclei during a relatively early epoch of BBN leading to the production of heavy elements. Constraints on the abundance of X0 are derived from observations of primordial light element abundances. Particle models which predict long-lived colored particles with lifetimes longer than ~200 s are rejected. This scenario prefers the production of 9Be and 10B. There might, therefore, remain a signature of the X particle on primordial abundances of those elements. Possible signatures left on light element abundances expected in four different models are summarized.

scholarly journals Limits on brane-world and particle dark radiation from big bang nucleosynthesis and the CMB

2017 ◽  
Vol 26 (08) ◽  
pp. 1741007 ◽  
Author(s):  
N. Sasankan ◽  
Mayukh R. Gangopadhyay ◽  
G. J. Mathews ◽  
M. Kusakabe
Keyword(s):  
Energy Density ◽  
Power Spectrum ◽  
Light Element ◽  
Reaction Rates ◽  
Big Bang ◽  
Brane World ◽  
Expansion Rate ◽  
Big Bang Nucleosynthesis ◽  
Dark Radiation ◽  
Element Abundances

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 (5D) RS-II brane-world cosmology. In this paper, we consider the constraints on both the meanings of dark radiation-based upon the newest results for light-element nuclear reaction rates, observed light-element abundances and the power spectrum of the Cosmic Microwave Background (CMB). Adding dark radiation during big bang nucleosynthesis (BBN) alters the Friedmann expansion rate causing the nuclear reactions to freeze out at a different temperature. This changes the final light element abundances at the end of BBN. Its influence on the CMB is to change the effective expansion rate at the surface of the last scattering. We find that the BBN constraint reduces the allowed range for both types of dark radiation at 10[Formula: see text]Mev to between [Formula: see text] and [Formula: see text] of the total background energy density at 10[Formula: see text]Mev. Combining this result with fits to the CMB power spectrum, produces different results for particle versus brane-world dark radiation. In the brane-world, the range decreases from [Formula: see text] to [Formula: see text]. Thus, we find that the ratio of dark radiation to the background total relativistic mass energy density [Formula: see text] is consistent with zero although there remains a very slight preference for a positive (rather than negative) contribution.

scholarly journals Dark matter annihilation in the universe

2014 ◽  
Vol 30 ◽  
pp. 1460256 ◽  
Author(s):  
Pierre Salati
Keyword(s):  
Dark Matter ◽  
Galactic Halo ◽  
Light Element ◽  
Big Bang ◽  
Microwave Background ◽  
Dark Matter Annihilation ◽  
Element Abundances ◽  
Primordial Plasma ◽  
Relic Abundance ◽  
The Universe

The astronomical dark matter is an essential component of the Universe and yet its nature is still unresolved. It could be made of neutral and massive elementary particles which are their own antimatter partners. These dark matter species undergo mutual annihilations whose effects are briefly reviewed in this article. Dark matter annihilation plays a key role at early times as it sets the relic abundance of the particles once they have decoupled from the primordial plasma. A weak annihilation cross section naturally leads to a cosmological abundance in agreement with observations. Dark matter species subsequently annihilate — or decay — during Big Bang nucleosynthesis and could play havoc with the light element abundances unless they offer a possible solution to the 7 Li problem. They could also reionize the intergalactic medium after recombination and leave visible imprints in the cosmic microwave background. But one of the most exciting aspects of the question lies in the possibility to indirectly detect the dark matter species through the rare antimatter particles — antiprotons, positrons and antideuterons — which they produce as they currently annihilate inside the galactic halo. Finally, the effects of dark matter annihilation on stars is discussed.

Nucleosynthesis

1986 ◽  
Vol 320 (1556) ◽  
pp. 557-564 ◽  
Keyword(s):  
Light Element ◽  
Hubble Constant ◽  
Big Bang ◽  
Element Abundances ◽  
Stellar Nucleosynthesis ◽  
Baryonic Density ◽  
Redshift Surveys ◽  
A Value ◽  
First Case ◽  
The Universe

Both Big-Bang and stellar nucleosynthesis have outcomes related to the density of baryonic matter, but whereas in the first case there is a standard model that makes very precise predictions of light element abundances as a function of the mean density of baryons in the Universe, in the second case various uncertainties permit only very limited conclusions to be drawn. As far as Big-Bang synthesis and the light elements are concerned, existing results on D, 3 He and 7 Li indicate a value of Ω N h 2 0 greater than 0.01 and less than 0.025, where Ω N is the ratio of baryonic density to the closure density and h 0 is the Hubble constant in units of 100 km s -1 Mpc -1 ; probably 0.5 < h 0 < 1. New results on the primordial helium abundance give a still tighter upper limit to Ω N ,Ω N h 2 0 < 0.013, which when compared with redshift surveys giving Ω > 0.05 implies that the observed matter can all be baryonic only if the various uncertainties are stretched to their limits.

scholarly journals Big bang nucleosynthesis: an accurate determination of light element yields

2000 ◽  
Vol 568 (1-2) ◽  
pp. 421-444 ◽  
Author(s):  
S. Esposito ◽  
G. Mangano ◽  
G. Miele ◽  
O. Pisanti
Keyword(s):  
Accurate Determination ◽  
Light Element ◽  
Big Bang ◽  
Big Bang Nucleosynthesis

NEUTRINO MASS AND COLD DARK MATTER PARTICLES IN BIG-BANG NUCLEOSYNTHESIS

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2427-2442 ◽  
Author(s):  
TOSHITAKA KAJINO ◽  
MOTOHIKO KUSAKABE ◽  
KAZUHIKO KOJIMA ◽  
TAKASHI YOSHIDA ◽  
DAI G. YAMAZAKI ◽  
...  
Keyword(s):  
Dark Matter ◽  
Neutrino Mass ◽  
Critical Role ◽  
Massive Particle ◽  
Light Element ◽  
Dark Matter Particle ◽  
Big Bang ◽  
Particle Model ◽  
Mass Hierarchy ◽  
Big Bang Nucleosynthesis

Neutrino is a tiny weakly interacting massive particle, but it has strong impacts on various cosmological and astrophysical phenomena. Neutrinos play a critical role in nucleosynthesis of light-to-heavy mass elements in core-collapse supernovae. The light element synthesis is particularly affected by neutrino oscillation (MSW) effect through the ν-process. We propose first that precise determination of sin 2 2θ13 and mass hierarchy can be made by a theoretical study of the observed 7 Li /11 B ratio in stars and presolar grains which are produced from SN ejecta. Theoretical sensitivity in our proposed method is shown to be superior to ongoing long-baseline neutrino experiments for the parameter region 10−4 ≤ sin22θ13 ≤ 10−2. We secondly discuss how to constrain the neutrino mass Σmν from precise analysis of cosmic microwave background anisotropies in the presence of primordial magnetic field. We obtain an upper limit Σmν < 1.3 eV (2σ). Thirdly, we discuss decaying dark-matter particle model in order to solve the primordial lithium problems that the standard Big-Bang nucleosynthesis theory predicts extremely different 6 Li and 7 Li abundances from observations.

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