Primordial lithium - New reaction rates, new abundances, new constraints

Abstract

Newly measured nuclear reaction rates for <SUP>3</SUP>H(α, γ)<SUP>7</SUP>Li (higher than previous values) and <SUP>7</SUP>Li(p, α)<SUP>4</SUP>He (lower than previous values) are shown to increase the <SUP>7</SUP>Li yield from big bang nucleosynthesis for lower baryon-to-photon ratio (η ⪉ 4×10<SUP>10</SUP>). In addition, recent revisions in the <SUP>3</SUP>He(α, γ)<SUP>7</SUP>Be and the D(p, γ)<SUP>3</SUP>He rates enhance the high (η ⪆ 4×10<SUP>10</SUP>)<SUP>7</SUP>Li(<SUP>7</SUP>Be) production. New, independent determinations of Li abundances in extreme Population II stars are in excellent agreement with the earlier work of the Spites and give continued confidence in the use of <SUP>7</SUP>Li in big bang baryon density determinations. A review is made of the strengths and possible weaknesses of utilizing conclusions drawn from big bang lithium considerations. An Appendix discusses the null effect of a factor of 32 increase in the experimental rate for the D(d, γ)<SUP>4</SUP>He reaction.