Higgs Portal to Dark QED

TL;DR

This paper explores a minimal Higgs portal model with a light dark photon coupled to dark QED, analyzing its collider signatures such as long-lived particles and darkonium states at the LHC.

Contribution

It introduces a novel extension of the Higgs portal with a dark photon and studies its distinctive collider phenomenology and potential for experimental probing.

Findings

Dark photon can lead to long-lived signatures at the LHC.

Higgs decays into dark photon or darkonium produce unique collider signals.

Parameter space can be explored via energy and lifetime measurements.

Abstract

We introduce a light dark photon $A_\mu^\prime$ to the minimal Higgs portal model, by coupling the Higgs boson to "dark QED" containing fermionic dark matter, which gives rise to rich and interesting collider phenomenology. There are two prominent features in such a simple extension -- the Higgs boson could have decays into the long-lived dark photon through the "mono-$A^\prime$ channel," or into multiple collimated leptons via "darkonium," depending on the mixing parameter of the $A_\mu^\prime$ with the visible photon. We initiate a study on the possibility of probing the parameter space of the model in both the energy and the lifetime frontiers at the Large Hadron Collider.