Speaker: Chris Howk, Notre Dame University, Physics Dept
Abstract: The cosmic abundance of lithium continues to represent a conundrum, as predictions from standard theories of Big Bang nucleosynthesis are inconsistent with measurements in the atmospheres of the lowest-metallicity stars. This discrepancy may be caused by astrophysical effects, such as the destruction of Li in the stars over their lifetimes, although no fully satisfactory astrophysical explanation has been proposed. Alternatively, it may also be explained by new physics in the early universe, e.g., by the early decay of particle dark matter. We are following an alternate approach to studying the cosmic Li abundance: the use of interstellar gas-phase Li in low-metallicity galaxies as a constraint on the primordial abundance and the cosmic evolution of Li. I will present measurement of gas-phase Li in the Small Magellanic Cloud, the first such measurement beyond the Milky Way. I will discuss the implications of our measurements and the prospects for future advances in this area.