The dark side of the proton

TL;DR

This paper explores how a light baryonic dark photon could influence proton structure and Drell-Yan processes at the LHC, proposing a method to set bounds on dark photon properties through PDF modifications.

Contribution

It introduces the concept of a dark photon PDF within proton structure and analyzes its impact on high-energy collision observables at the LHC.

Findings

Dark photon presence distorts quark and gluon PDFs.

LHC data can set competitive bounds on dark photon parameters.

Dark photon effects are observable in Drell-Yan invariant mass tails.

Abstract

We study the sensitivity of the High-Luminosity LHC to a light baryonic dark photon B, primarily coupled to quarks, as a constituent of the proton. This is achieved by allowing for a dark photon parton distribution function (PDF) in the PDF evolution equations. Depending on the mass and coupling of the dark photon, the evolution of standard quark and gluon PDFs is distorted to varying degrees. By analysing the effect of the dark photon on the tails of Drell-Yan invariant mass distributions, we demonstrate the potential of the LHC in determining competitive bounds on dark photon parameter space.