Nonabelian Kinetic Mixing in a Confining Phase

TL;DR

This paper explores a novel nonabelian kinetic mixing mechanism in a confining dark sector with SU(N) symmetry, leading to composite dark photons and new detection portals, constrained by various experimental and cosmological data.

Contribution

It introduces a model where nonabelian kinetic mixing occurs in a confining phase, producing composite dark photons and multiple interaction portals with the standard model.

Findings

Massive dark photons emerge without spontaneous symmetry breaking.

Multiple composite vectors can kinetically mix via a heavy mediator.

The model's viability is constrained by collider, decay, detection, and cosmological data.

Abstract

Dark matter from a hidden sector with SU($N$) gauge symmetry can have a nonabelian kinetic mixing portal with the standard model. The dark photon becomes massive in the confining phase without the need for spontaneous symmetry breaking. Depending on the particle content of the dark sector, there can be two or more composite vectors that get kinetic mixing through a heavy mediator particle $X$. This provides a model of composite dark photons giving a portal for direct detection of dark baryons. Avoiding exotic charged relics requires additional couplings allowing $X$ to decay to dark quarks and standard model fields, leading to further portals between the dark matter and the standard model. We comprehensively study the constraints on such models from colliders, rare decays, direct detection, and big bang nucleosynthesis.