Experimental, computational, and observational analysis of primordial nucleosynthesis

Conference · Wed Jan 01 00:00:00 EST 1992

OSTI ID:6811598

Smith, M S

We have made a comprehensive evaluation of the standard theory of primordial nucleosynthesis, by (a) determining the nuclear reactions most important for light element production in the Big Bang; (b) conducting a detailed study of the rates and uncertainties of these reactions (c) employing a Monte Carlo analysis to properly evaluate uncertainties in the computed elemental abundances arising from reaction rate uncertainties; and (d) comparing the predicted abundances of d, [sup 3]He, [sup 4]He, and [sup 7]Li to those inferred from observations. We find a consistent agreement for 2.68 [times] 10[sup [minus]10] [le] [eta] [le] 3.77 [times] 10[sup [minus]10], where [eta] is the baryon-to-photon ratio, thereby supporting the standard Big Bang nucleosynthesis (SBBN) theory. The corresponding constraint on the baryon density parameters is 0.01 [le] [Omega][sub b] [le] 0.09, where the primordial d+[sup 3]He ([sup 4]He) abundance sets the lower (upper) bound. We find that the new reaction rates increase the [eta] upper bound from [sup 7]Li by 45%, and that inconsistencies in SBBN will arise if the primordial [sup 4]He mass fraction is less than 0.237 or if the primordial [sup 7]Li abundance is at the Pop I level. For slightly non-standard primordial nucleosynthesis models, comparisons to primordial abundances show that the number of neutrino families N[sub nu] is limited to N[sub nu] [le] 3.3. Specifically, 3.5 neutrino families (3 Dirac [nu]'s plus one Majorana [nu]) or more are ruled out at the 2-[sigma] level. The dependence of the N[sub nu] upper limit on the abundances limits has been parameterized.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE; National Science Foundation (NSF); USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6811598
• Report Number(s): CONF-9209239-5; ON: DE93006626; CNN: PHY88-17296; PHY91-15574
• Resource Relation: Conference: Workshop on nuclear physics in the universe, Oak Ridge, TN (United States), 24-26 Sep 1992
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
NUCLEOSYNTHESIS
COSMOLOGICAL MODELS
ELEMENT ABUNDANCE
MONTE CARLO METHOD
NEUTRINOS
NUCLEAR REACTION KINETICS
NUCLEAR REACTIONS
ABUNDANCE
CALCULATION METHODS
ELEMENTARY PARTICLES
FERMIONS
KINETICS
LEPTONS
MASSLESS PARTICLES
MATHEMATICAL MODELS
REACTION KINETICS
SYNTHESIS
661300* - Other Aspects of Physical Science- (1992-)
663300 - Nuclear Reactions & Scattering
General- (1992-)