Speaker: Ciaran O'Hare
Affiliation: The University of Sydney
Abstract
A hypothetical particle called the axion could well be the next elementary particle we discover. The reason for believing the axion should exist is because it would solve two outstanding problems in physics at once: the reason why the neutron does not possess an electric dipole moment, and the identity of dark matter. Furthermore, unlike many searches for new physics, there is a good chance we will know whether or not the axion solution to these two problems is correct within our lifetimes. This is thanks to a flourishing campaign of astronomical observations and laboratory experiments on the horizon. However, to perform these searches, we need to know how many axions were produced after the Big Bang and the manner in which they became distributed across space. After axions are produced in the high temperatures of the early Universe, they undergo a rich and complex evolutionary story. In this talk, I will tell this story, and in doing so, I will reveal several theoretical problems which emerge that have the potential to hinder our attempts to discover the axion even if it exists (as well as some new opportunities that could potentially make this discovery occur sooner).
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Venue
Room: 309
