Testing the lepton content of the proton at HERA and EIC

TL;DR

This paper proposes a method to test the lepton parton distribution functions of the proton by analyzing di-lepton and Z boson production at HERA and EIC, providing a way to validate theoretical predictions of leptonic content.

Contribution

It introduces a novel experimental approach to validate lepton PDFs of the proton using collider data from HERA and EIC.

Findings

Measurable event yields for lepton-induced processes at HERA and EIC.

Potential to experimentally test lepton PDFs of the proton.

Demonstrates feasibility despite small lepton PDF values.

Abstract

Although protons are baryons with an overall vanishing lepton number, they possess a non-trivial leptonic content arising from quantum fluctuations which can be described by lepton parton distribution functions (PDFs) of the proton. These PDFs have been recently computed and can be used to define lepton-induced processes at high-energy colliders. In this article, we propose a novel way to test the computation of lepton PDFs of the proton by analyzing both non-resonant di-lepton and resonant Z gauge boson production processes induced by leptons within the proton at proton-electron colliders like HERA and EIC. Despite the fact that lepton PDFs of the proton are known to be small, this work demonstrates that both processes imply a measurable yield of events at HERA and EIC, which could be used to test these PDFs.