Speaker
Description
Over 99.9 percent of the baryonic mass of all the universe comes from the nuclei at the center of every atom. These nuclei are made of protons and neutrons that themselves formed a few microseconds after the big bang as the primordial quark-gluon plasma cooled and condensed. Approximately three minutes after the Big Bang, the abundances of the primordial elements in the universe include protons, deuterons, 3He, 4He, and trace amounts of lithium and beryllium. Theoretical predictions for the primordial abundances of these elements are in good agreement and consistent with observations of the abundances for deuterons, 3He, and 4He but not for lithium. The lithium abundance predictions are 2.5 - 3.0 times higher than observed values even when the correct baryon-to-photon ratio of the Universe obtained from anisotropies of cosmic microwave background radiation is included. This discrepancy between the predicted primordial abundance of lithium from Big Bang nucleosynthesis and the observed abundances is known as the cosmological Li problem. We propose tritium induced reactions as potential avenues for impacting the resulting Li abundances. Tritium is neutron-rich and has a half-life of 12.323 years. Tritium was not thought to have any significant impact on long-lived stellar scenarios and therefore neglected. I will discuss some potential paths to reduce the Li abundance. Tritium reactions may also be important in the deaths of stars with core-collapse supernovae, or neutron star mergers where the synthesized elements are disassociated to be synthesized again.