• Nuclear, Particle, Astroparticle and Cosmology (NUPAC) Seminars

May 3, 2024 11:00 AM
PAIS-2540, PAIS

Host:

Dinesh Loomba

Presenter:

Dr. Dave Kaiser (MIT)

For fifty years, physicists have been stymied by the puzzle of dark matter. From the motion of enormous clusters of galaxies to the rate at which individual galaxies spin, decades of careful measurements have indicated that all the visible matter astronomers can observer contributes a tiny fraction to the total mass contained within the observable universe. Many hypothetical new particles have been proposed, which might play the role of dark matter, from weakly interacting massive particles (WIMPs) to ultralight particles such as axions. Yet after decades of meticulous experiments, no clear evidence of any such particle has turned up. In recent years, many physicists and cosmologists have returned to a different idea: what if all of dark matter consists of ordinary matter locked up within black holes, which could have formed during the earliest moments in cosmic history? Theorists have identified several plausible mechanisms by which a population of such primordial black holes could have formed, and recent observations have constrained — but not eliminated — the range of masses within which primordial black holes could constitute all of dark matter while remaining consistent with various observations. More recently, several groups around the world (including my own) have proposed new tests that could yield evidence that primordial black holes really do exist and contribute to the dark matter abundance.