"Freeze-in Dark Matter," James Unwin (University of Notre Dame)

Monday, November 24, 2014 - 3:00pm to 4:00pm
TEP Seminars

TEP Seminar

Physics and Astronomy Building (PAB) Room 4-330
Monday, November 24, 2014

Guest Speaker: James Unwin (University of Notre Dame)

Talk Title: "Freeze-in Dark Matter"


In the freeze-out paradigm of dark matter the dark matter is initially in thermal equilibrium and its abundance evolves with its equilibrium distribution until it decouples from the thermal bath. In models of freeze-in dark matter it is supposed that the dark matter number density is initially negligible, but over time an abundance suitable to match the relic density is produced due to interactions in the thermal bath involving a suppressed portal operator. For the dark matter abundance to be initially negligible, and subsequently set by the freeze-in mechanism (rather than freeze-out), the hidden sector must be thermally decoupled from the visible sector bath at all times, which implies that the portal operators must be extremely small. The thermal history is drastically different depending on whether the portal operator is due to both renormalisable and non-renormalisable operators, and I will discuss both scenarios.

PAB 4-708