Dark matter and spin-1 milli-charged particles

TL;DR

This paper introduces a minimal, renormalizable model for massive, milli-charged spin-1 particles as gauge bosons of a broken non-abelian symmetry, proposing a new dark matter candidate with specific phenomenological constraints.

Contribution

It presents the first minimal model for spin-1 milli-charged particles, extending the Standard Model with a new gauge symmetry and dark Higgs mechanism.

Findings

The model is unitary and renormalizable.

Stable milli-charged spin-1 particles can serve as dark matter.

Phenomenological constraints limit the parameter space.

Abstract

New physics scenarios beyond the Standard Model predict the existence of milli-charged particles. So far, only spin-1/2 and spin-0 milli-charged particles have been considered in literature, leaving out the interesting case of spin-1. We propose a minimal unitary and renormalizable model of massive milli-charged vector particles. Unitarity requires that these particles are gauge bosons of a non-abelian spontaneously broken gauge symmetry. The minimal scenario then consists of an extended Standard Model gauge group $SU(2)_L \times U(1)_Y \times SU(2)_D$ together with a $SU(2)_D$ dark Higgs boson responsible for the symmetry breaking in the dark sector. By imposing that the dark Higgs multiplet has a non-vanishing milli-hypercharge, stable milli-charged spin-1 fields arise thereby providing a potential dark matter candidate. We analyse the phenomenological constraints on this scenario and discuss their implications.