Big bang nucleosynthesis limit on N_nu
ArXiv hep-ph/9901404 (1999)
Authors:
E Lisi, Subir Sarkar, FL Villante
Abstract:
Recently we presented a simple method for determining the correlated
uncertainties of the light element abundances expected from big bang
nucleosynthesis, which avoids the need for lengthy Monte Carlo simulations. We
now extend this approach to consider departures from the Standard Model, in
particular to constrain any new light degrees of freedom present in the thermal
plasma during nucleosynthesis. Since the observational situation regarding the
inferred primordial abundances has not yet stabilized, we present illustrative
bounds on the equivalent number of neutrino species N_nu for various
combinations of individual abundance determinations. Our 95% C.L. bounds on
N_nu range between 2 and 4, and can easily be reevaluated using the technique
provided when the abundances are known more accurately.
