Monday, October 15, 2018
2:30PM - 3:30PM
HP4351
Speaker: Alexandre Poulin
Although Dark Matter (DM) makes up a significant part of the all the
energy in the Universe, lack experimental DM measurements means that there is
no clear path or direction for theorists. Because of this,there are many particle
physics models and ways to theoretically produce DM, one such mechanism is
thermal freeze-out. In this scenario, the DM was in thermal contact with the
Standard Model and decoupled once the rate of reaction became comparable to
the expansion rate of the Universe. This can be a complicated calculation and
many approximations are typically made, obscuring the physics when making
modifications to the standard picture. We will explore the concepts behind
freeze-out in such a way that generalizations to the standard picture become
clear, well-motivated path for continued research. We will then go down two such
path by considering modified expansion rate and will be shown that the results
are not obtain as simply as one would expect if they were only looking at the
typical freeze-out equations. Next, we will look at the case with multiple DM
species as a generalization to the single particle case revealing that general
interactions between DM species can lead to potentially many important effects.