Astrophysical Signatures of Asymmetric Dark Matter Bound States

TL;DR

This paper explores the properties and cosmological implications of large, stable bound states called nuggets in asymmetric dark matter, highlighting their potential observational signatures and constraints from cosmology and particle physics.

Contribution

It introduces a generic model for ADM nuggets, analyzes their formation, stability, and astrophysical signatures, and derives bounds from cosmological and indirect detection constraints.

Findings

Nuggets can have masses up to about 10^{16} GeV at synthesis freeze-out.

Self-interaction constraints limit nugget masses and influence galaxy core structures.

Indirect detection experiments constrain models with Higgs-mixed scalar mediators.

Abstract

Nuggets---very large stable bound objects arising in the presence of a sufficiently attractive and long-range force and in the absence of a dark Coulomb force---are a smoking gun signature for Asymmetric Dark Matter (ADM). The cosmology of ADM nuggets is both generic and unique: nuggets feature highly exothermic fusion processes, which can impact the shape of the core in galaxies, as well as give rise to rare dark star formation. We find, considering the properties of nuggets in a generic extended nuclear model with both attractive and repulsive forces, that self-interaction constraints place an upper bound on nugget masses at the freeze-out of synthesis in the ballpark of $M_{\rm fo} \lesssim 10^{16}$ GeV. We also show that indirect detection strongly constrains models where the scalar mediator binding the nuggets mixes with the Higgs.