Speaker: Michel Tytgat (ULB)
Title: The ins and outs of a hidden sector dark matter
Abstract: In this talk, I will discuss various aspects of dark matter from a hidden sector (HS). To be concrete, I will focus on dark QED and kinetic mixing, but the scope is in principle broader. First, I will discuss some rather recent results (taking into account the time dilation caused by Covid-19) that concern the general classification of production mechanisms for dark matter through a portal, from freeze-in to freeze-out. Some of these mechanisms lead to a HS that is in thermal equilibrium but at T'≠T, the latter being the temperature of the SM particles. This will bring me to a mapping of possible thermal DM candidates as a function of T'/T. An interesting outcome is the possibility that T'≫T in the early universe. I will discuss the history of such a hot dark sector and the possible consequences on DM candidates.