Multi-lepton events at HERA

TL;DR

This paper investigates high transverse momentum multi-lepton events at HERA, comparing experimental data with simulations, and explores the potential role of doubly-charged Higgs bosons in explaining observed anomalies.

Contribution

It provides the first detailed comparison of multi-lepton events at HERA with gamma-gamma collision simulations and analyzes the possibility of doubly-charged Higgs bosons as a source.

Findings

Measured total and differential cross sections for multi-lepton events.

Observed high invariant mass multi-electron events.

No definitive evidence for doubly-charged Higgs bosons.

Abstract

Events containing high-$P_T$ multi-leptons were sought at HERA by the H1 and ZEUS collaborations. Experimental data were compared to simulations of $\gamma \gamma \to l^+ l^-$ processes, and H1 extracted the total and differential cross sections of the processes. The doubly-charged Higgs, which decays into lepton pairs, was analysed by H1 as a possible source of the multi-electron events, which have been observed at high invariant masses.