High Energy Physics Seminar

Series: High Energy Physics Seminar Series

Freeze-in Dark Matter

James Unwin, University of Notre Dame,

note: special date

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.

Event Sponsors:

For more information, please contact Carol Silberstein by phone at 6685 or by email at [email protected] or visit http://theory.caltech.edu/people/carol/seminar.html.