FIMP dark matter in the scotogenic model at low-reheating temperatures

The scotogenic model offers an attractive framework that explains light neutrino masses while accommodating a viable dark matter candidate. In this work, we study the phenomenology of singlet fermion dark matter, $N_1$, produced via the freeze-in mechanism characterized by an instantaneous low reheating temperature, $T_{\text{rh}}$. We explore the model’s viable parameter space, incorporating current bounds from lepton flavor violation ($\mu \to e\gamma$) and direct detection limits. We show that low-reheating scenarios significantly reshape the viable region for $N_1$ dark matter, improving prospects for testing the scotogenic model in the FIMP scenario while keeping it consistent with current lepton flavor violation and cosmological bounds.