Two Component Feebly Interacting Massive Particle (FIMP) Dark Matter

TL;DR

This paper investigates a two-component scalar FIMP dark matter model where particles are produced via freeze-in, extending the Standard Model with two stable gauge singlet scalars, and explores viable mass ranges and interaction limits.

Contribution

It introduces a novel two-component scalar FIMP dark matter model with specific symmetry protections and analyzes its viable parameter space and mass limits.

Findings

Viable FIMP mass regions identified for the two scalar components.

Upper mass limits derived based on self-interaction constraints.

Model remains consistent with freeze-in production mechanism.

Abstract

We explore the idea of an alternative candidate for particle dark matter namely Feebly Interacting Massive Particle (FIMP) in the framework of a two component singlet scalar model. Singlet scalar dark matter has already been demonstrated to be a viable candidate for WIMP (Weakly Interacting Massive Particle) dark matter in literature. In the FIMP scenario, dark matter particles are slowly produced via "thermal frreze-in" mechanism in the early Universe and are never abundant enough to reach thermal equilibrium or to undergo pair annihilation inside the Universe's plasma due to their extremely small couplings. We demonstrate that for smaller couplings too, required for freeze-in process, a two component scalar dark matter model considered here could well be a viable candidate for FIMP. In this scenario, the Standard Model of particle physics is extended by two gauge singlet real scalars whose stability is protected by an unbroken $Z_{2}\times {Z'}_{2}$ symmetry and they are assumed to acquire no VEV after Spontaneous Symmetry Breaking. We explore the viable mass regions in the present two scalar DM model that is in accordance with the FIMP scenario. We also explore the upper limits of masses of the two components from the consideration of their self interactions.