Dark matter with two- and many-body decays and supernovae type Ia

TL;DR

This paper explores models of decaying dark matter producing relativistic particles, analyzing their evolution and constraining their properties using supernovae type Ia data, revealing limits on decay lifetimes and relativistic fractions.

Contribution

It introduces new models of dark matter decay with specific daughter particle configurations and derives their cosmological implications and observational constraints.

Findings

Relativistic fraction of 1% or more excludes lifetimes under 10 Gyrs.

Higher relativistic fractions impose stricter lifetime constraints.

Models are constrained by supernovae type Ia observations.

Abstract

We present a decaying dark matter scenario where the daughter products are a single massless relativistic particle and a single, massive but possibly relativistic particle. We calculate the velocity distribution of the massive daughter particle and its associated equation of state and derive its dynamical evolution in an expanding universe. In addition, we present a model of decaying dark matter where there are many massless relativistic daughter particles together with a massive particle at rest. We place constraints on these two models using supernovae type Ia observations. We find that for a daughter relativistic fraction of 1% and higher, lifetimes of at least less than 10 Gyrs are excluded, with larger relativistic fractions constraining longer lifetimes.