Forbidden Dark Matter

TL;DR

This paper introduces Forbidden Dark Matter, a model where DM annihilates into heavier states early on, evading CMB constraints and allowing a wide mass range, with testable predictions like self-interactions and direct detection signals.

Contribution

It presents a novel Forbidden DM framework with exponential mass hierarchy and demonstrates its consistency with cosmological constraints and potential experimental tests.

Findings

DM can have masses from keV to weak scale within this model

Annihilation cross section is exponentially suppressed, enabling late-time freeze-out

Model predicts observable self-interactions and signals in direct detection experiments

Abstract

Dark Matter (DM) may be a thermal relic that annihilates into heavier states in the early Universe. This Forbidden DM framework accommodates a wide range of DM masses from keV to weak scales. An exponential hierarchy between the DM mass and the weak scale follows from the exponential suppression of the thermally averaged cross section. Stringent constraints from the cosmic microwave background are evaded because annihilations turn off at late times. We provide an example where DM annihilates into dark photons, which is testable through large DM self-interactions and direct detection.