The dynamics and detection possibility of a pseudo FIMP in the presence of thermal Dark Matter

Interaction between two dark matter (DM) components plays a
crucial role in DM production, dynamics and phenomenology in
multicomponent DM scenarios. We propose and study a new kind of DM, called
pseudo-FIMP (pFIMP), which can be realised in a two-component DM setup.
The pFIMP is feebly connected to the visible sector but remains in thermal
equilibrium by sufficient interaction with a thermal DM partner before
freezing out to achieve under abundance. Despite its lack of direct
interactions with the visible sector, pFIMP can still be probed
experimentally via loop processes involving the thermal DM component. In
this talk, we discuss the dynamics of pFIMP and its loop-induced detection
possibilities in the presence of a thermal DM when both are rendered
stable under symmetry. The pFIMP scenario is also realizable when the
thermal DM is of sub-GeV mass, resembling a Strongly Interacting Massive
Particle (SIMP). Under a single discrete symmetry, a heavy dark sector
particle can become a long-lived dark matter candidate when its lifetime
is significantly enhanced, surpassing the universe's age for specific
parameter choices. In such a scenario, the possibility of a pFIMP arises
as an equally plausible candidate. This provides a rich phenomenology and
larger available parameter space. We briefly discuss such possibility for
symmetry, highlighting the cases of and symmetries specifically.