Neutrino Portal to FIMP Dark Matter with an Early Matter Era

Understand

We study the freeze-in production of Feebly Interacting Massive Particle (FIMP) dark matter candidates through a neutrino portal.

• We consider a hidden sector comprised of a fermion and a complex scalar, with the lightest one regarded as a FIMP candidate.
• We implement the Type-I Seesaw mechanism for generating the masses of the Standard Model (SM) neutrinos and consider three heavy neutrinos, responsible for mediating the interactions between the hidden and the SM sectors.
• We assume that an early matter-dominated era (EMDE) took place for some period between inflation and Big Bang Nucleosynthesis, making the Universe to expand faster than in the standard radiation-dominated era.