An intermediate framework between WIMP, FIMP, and EWIP dark matter

TL;DR

This paper introduces an intermediate dark matter framework combining features of WIMP, FIMP, and EWIP models, analyzing a singlet scalar example to explore relic density and implications for heavy dark matter and inflation.

Contribution

It proposes a novel dark matter scenario blending key features of existing frameworks and provides a detailed analysis using the singlet scalar model.

Findings

Relic density depends on the reheating temperature.

Viable parameter space for heavy dark matter particles.

Potential link between dark matter properties and inflation.

Abstract

WIMP (Weakly Interacting Massive Particle), FIMP (Feebly interacting Massive Particle) and EWIP (Extremely Weakly Interacting Particle) dark matter are different theoretical frameworks that have been postulated to explain the dark matter. In this paper we examine an intermediate scenario that combines features from these three frameworks. It consists of a weakly interacting particle --a la WIMP-- that does not reach thermal equilibrium in the early Universe --a la FIMP-- and whose relic density is determined by the reheating temperature of the Universe --a la EWIP. As an example, an explicit realization of this framework, based on the singlet scalar model of dark matter, is analyzed in detail. In particular, the relic density is studied as a function of the parameters of the model, and the new viable region within this intermediate scenario is determined. Finally, it is shown that this alternative framework of dark matter allows for arbitrarily heavy dark matter particles and that it suggests a connection between dark matter and inflation.