Speaker
Description
Big-bang nucleosynthesis (BBN) describes the formation of the lightest nuclides in the first minutes of cosmic time, and is a central pillar of the hot big-bang cosmology. Standard BBN combines this with the Standard Model of particle physics and nuclear cross section measurements. These allow us to make tight predictions for the primordial light element abundances, some of which are stable, but mass-7 is mostly produced as the radioisotope 7Be that later decays to 7Li. We will discuss recent observational and theoretical activity concerning 7Li and 4He. Lithium observations (in metal-poor halo stars) have long disagreed with BBN predictions, leading to the cosmic "lithium problem." But recent work strengthens the case for a solution to this problem involving stellar destruction of lithium. Turning to 4He, we will present new observations that achieved a leap in precision. We will discuss the implications of these observations for cosmology and physics beyond the Standard Model. And we will conclude with recommendations for new astrophysical observations and nuclear physics measurements that can make BBN an even more powerful probe of the early Universe and new physics.
| Career stage | Tenured mid-to-late-career researcher |
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