Center for Theoretical Physics of the Universe (CTPU)

Spontaneous Freeze Out of Dark Matter From an Early Thermal Phase Transition

by Dr. Lucien Heurtier (University of Arizona)

Wednesday, 22 January 2020 from to (Asia/Seoul)
at CTPU Seminar Room
Fourth floor IBS Building, 55, Expo-ro, Yuseong-gu, Daejeon, Korea, 34126
Description
I will introduce a new paradigm for the thermal production of dark matter in the early universe, in which dark-matter particles acquire their mass and freeze out spontaneously from the thermal bath after a dark phase transition takes place. The decoupling arises because the dark-matter particles become suddenly non-relativistic and not because of any decay channel becoming kinematically close. I will present a minimal scenario in which a scalar and a fermionic dark-matter are in thermal equilibrium with the Standard-Model bath. I will present the finite temperature corrections to the scalar potential and identify a region of the parameter space where the fermionic dark-matter mass spontaneously jumps over the temperature when the dark phase transition happens. I will explore the phenomenological implications of such a model in simple cases and show that the annihilation cross section of dark-matter particles has to be larger by more than one order of magnitude as compared to the usual constant-mass WIMP scenario in order to accomodate the correct relic abundance. I will finally show that in the spontaneous freeze out regime a TeV-scale fermionic dark-matter that annihilates into leptons through s-wave processes can be accessible to detection in the near future.
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