Abstract
Primordial nucleosynthesis provides (with the microwave background radiation) one of the two quantitative experimental tests of the hot Big Bang cosmological model (versus alternative explanations for the observed Hubble expansion). The standard homogeneous-isotropic calculation fits the light element abundances ranging from 1H at 76% and 4He at 24% by mass through 2H and 3He at parts in 105 down to 7Li at parts in 1010. It is also noted how the recent Large Electron Positron Collider (and Stanford Linear Collider) results on the number of neutrinos (Nnu) are a positive laboratory test of this standard Big Bang scenario. The possible alternate scenario of quark-hadron-induced inhomogeneities is also discussed. It is shown that when this alternative scenario is made to fit the observed abundances accurately, the resulting conclusions on the baryonic density relative to the critical density (Omegab) remain approximately the same as in the standard homogeneous case, thus adding to the robustness of the standard model and the conclusion that Omegab approximately 0.06. This latter point is the driving force behind the need for nonbaryonic dark matter (assuming total density Omegatotal = 1) and the need for dark baryonic matter, since the density of visible matter Omegavisible < Omegab. The recent Population II B and Be observations are also discussed and shown to be a consequence of cosmic ray spallation processes rather than primordial nucleosynthesis. The light elements and Nnu successfully probe the cosmological model at times as early as 1 sec and a temperature (T) of approximately 10(10) K (approximately 1 MeV). Thus, they provided the first quantitative arguments that led to the connections of cosmology to nuclear and particle physics.
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- Applegate JH, Hogan CJ, Scherrer RJ. Cosmological baryon diffusion and nucleosynthesis. Phys Rev D Part Fields. 1987 Feb 15;35(4):1151–1160. doi: 10.1103/physrevd.35.1151. [DOI] [PubMed] [Google Scholar]
- Freese K, Adams FC. Hadron bubble evolution into the quark sea. Phys Rev D Part Fields. 1990 Apr 15;41(8):2449–2461. doi: 10.1103/physrevd.41.2449. [DOI] [PubMed] [Google Scholar]
- Mampe W, Ageron P, Bates C, Pendlebury JM, Steyerl A. Neutron lifetime measured with stored ultracold neutrons. Phys Rev Lett. 1989 Aug 7;63(6):593–596. doi: 10.1103/PhysRevLett.63.593. [DOI] [PubMed] [Google Scholar]
- Reeves H., Fowler W. A., Hoyle F. Galactic cosmic ray origin of Li, Be and B in stars. Nature. 1970 May 23;226(5247):727–729. doi: 10.1038/226727a0. [DOI] [PubMed] [Google Scholar]
- Smith K. A., Robertson P. D. Effect of ethylene on root extension of cereals. Nature. 1971 Nov 19;234(5325):148–149. doi: 10.1038/234148a0. [DOI] [PubMed] [Google Scholar]