Abstract
A new evaluation of the constraint on the number of light neutrino species (N) from big bang nucleosynthesis suggests a discrepancy between the predicted light element abundances and those inferred from observations, unless the inferred primordial He4 abundance has been underestimated by 0.0140.004 (1) or less than 10% (95% C.L.) of He3 survives stellar processing. With the quoted systematic errors in the observed abundances and a conservative chemical evolution parametrization, the best fit to the combined data is N=2.10.3 (1) and the upper limit is N<2.6 (95% C.L.). The data are inconsistent with the standard model (N=3) at the 98.6% C.L.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3977-3980 |
| Number of pages | 4 |
| Journal | Physical review letters |
| Volume | 75 |
| Issue number | 22 |
| DOIs | |
| State | Published - 1995 |
All Science Journal Classification (ASJC) codes
- General Physics and Astronomy