The Cosmology of Composite Inelastic Dark Matter

TL;DR

This paper explores the early Universe cosmology of a composite inelastic dark matter model, where dark matter is made of mesons with specific mass splittings, potentially explaining the DAMA/LIBRA signal.

Contribution

It provides a detailed analysis of the cosmological evolution and formation of composite dark matter particles with inelastic properties in a minimal model.

Findings

Different dark matter hadron configurations depending on mass scales

Mechanism for inelastic scattering explaining DAMA/LIBRA

Cosmological synthesis of dark mesons and baryons

Abstract

Composite dark matter is a natural setting for implementing inelastic dark matter - the O(100 keV) mass splitting arises from spin-spin interactions of constituent fermions. In models where the constituents are charged under an axial U(1) gauge symmetry that also couples to the Standard Model quarks, dark matter scatters inelastically off Standard Model nuclei and can explain the DAMA/LIBRA annual modulation signal. This article describes the early Universe cosmology of a minimal implementation of a composite inelastic dark matter model where the dark matter is a meson composed of a light and a heavy quark. The synthesis of the constituent quarks into dark mesons and baryons results in several qualitatively different configurations of the resulting dark matter hadrons depending on the relative mass scales in the system.