Search for Anomalous Production of Di-lepton Events with Missing Transverse Momentum in e+e- Collisions at sqrt(s) = 183-209 GeV

TL;DR

This study analyzed 1317 di-lepton events with missing transverse momentum in e+e- collisions at 183-209 GeV, finding results consistent with the Standard Model and setting limits on new particle production.

Contribution

It provides the first comprehensive search for anomalous di-lepton events with missing momentum at these energies, establishing new constraints on supersymmetric particles and charged Higgs bosons.

Findings

No evidence for new phenomena was observed.

Upper limits were set on production cross-sections for sleptons, charginos, and charged Higgs bosons.

Mass limits for these particles were established.

Abstract

In total 1317 di-lepton events with significant missing transverse momentum were identified in a total data sample of 680 pb-1 collected at e+e- centre-of-mass energies ranging from 183 GeV to 209 GeV. The number of di-lepton events, the dependence on centre-of-mass energy, and the event properties are consistent with expectations from Standard Model processes, predominantly W+W- production with both W bosons decaying leptonically. This topology is also an experimental signature for the pair production of new particles that decay to a charged lepton accompanied by one or more invisible particles. No evidence for new phenomena is apparent. Upper limits are presented on the production cross-section multiplied by the relevant branching ratio squared for sleptons, leptonically decaying charginos and charged Higgs bosons. Mass limits are also given.