Events with Isolated Charged Leptons and Large Missing Transverse Momentum at HERA

Abstract

Striking events with isolated charged leptons, large missing transverse momentum and large transverse momentum of the hadronic final state were observed at the electron proton collider HERA in a data sample corresponding to a luminosity of about 130 pb-1. The H1 collaboration observed 11 events with isolated electrons or muons and with transverse momentum above 25 GeV. Only 3.4+-0.6 events were expected from Standard Model (SM) processes. Six of these events have a transverse momentum of greater than 40 GeV, while 1.3+-0.3 events were expected. The ZEUS collaboration observed good agreement with the SM. However, ZEUS found two events with a similar event topology, but tau leptons instead of electrons or muons in the final state. Only 0.2+-0.05 events were expected from SM processes. For various hypotheses the compatibility of the experimental results was investigated with respect to the SM and with respect to possible explanations beyond the SM. Prospects for the high-luminosity HERA-II data taking period are given.

References in corpus (8)

• LEPTO 6.5 - A Monte Carlo Generator for Deep Inelastic Lepton-Nucleon Scattering
• Search for Single Top Production at LEP
• New Neutral Gauge Bosons and New Heavy Fermions in the Light of the New LEP Data
• The Production of Single t-Quarks at LEP and HERA
• Observation of Events with an Isolated High Energy Lepton and Missing Transverse Momentum at HERA
• Isolated electrons and muons in events with missing transverse momentum at HERA
• A Multi-variate Discrimination Technique Based on Range-Searching
• W Production and the Search for Events with an Isolated High-Energy Lepton and Missing Transverse Momentum at HERA

Cited by in corpus (2)

• Events with Isolated Leptons and Missing Transverse Momentum and Measurement of W Production at HERA
• Searches for New Physics