Multi-lepton Production at High Transverse Momentum in electron-proton collisions at HERA

TL;DR

This paper reports measurements of multi-lepton production at high transverse momentum in electron-proton collisions at HERA, finding general agreement with the Standard Model but noting events with high di-electron mass where predictions are low.

Contribution

First measurement of multi-lepton production at high transverse momentum in electron-proton collisions at HERA, comparing results with Standard Model predictions.

Findings

Good overall agreement with Standard Model

Observation of events with di-electron mass above 100 GeV

Standard Model prediction is low in the high-mass domain

Abstract

Multi-electron and multi-muon production have been measured at high transverse momentum in electron-proton collisions at HERA.Good overall agreement is found with the Standard Model predictions, dominated by photon-photon interactions. Events are observed with a di-electron mass above 100 GeV, a domain where the Standard Model prediction is low.