Enhanced Long-Lived Dark Photon Signals at the LHC

TL;DR

This paper proposes a model with a hidden sector that predicts enhanced long-lived dark photon signals at the LHC, which can be distinguished from background using precision timing detectors, and explores current experimental constraints.

Contribution

The paper introduces a novel hidden sector model with two gauge U(1) bosons and a Dirac fermion, predicting distinctive long-lived dark photon signals detectable at the LHC.

Findings

Enhanced long-lived dark photon signals at the LHC compared to conventional models.

Potential discrimination of dark photon signals from background using timing detectors.

Analysis of current LHCb data and various experimental constraints on the model.

Abstract

We construct a model in which the standard model is extended by a hidden sector with two gauge $U(1)$ bosons. A Dirac fermion $\psi$ charged under both $U(1)$ fields is introduced in the hidden sector which can be a subcomponent of the dark matter in the Universe. Stueckelberg mass terms between the two new gauge $U(1)$ fields and the hypercharge gauge boson mediate the interactions between the standard model sector and the hidden sector. A remarkable collider signature of this model is the enhanced long-lived dark photon events at the LHC than the conventional dark photon models; the long-lived dark photons in the model can be discriminated from the background by measuring the time delay signal in the precision timing detectors which are proposed to be installed in the LHC upgrades and have an ${\cal O} (10)$ pico-second detection efficiency. Searches with current LHCb data are also investigated. Various experimental constraints on the model including collider constraints and cosmological constraints are also discussed.