Search for Stable and Long-Lived Massive Charged Particles with the OPAL Detector at LEP in e+e- Collisions at \sqrt{s}=130-183 GeV

TL;DR

This study searched for stable, long-lived charged particles in e+e- collisions at LEP energies, setting mass and cross-section limits, and excluding certain supersymmetric particles below specific mass thresholds.

Contribution

The paper provides the first comprehensive search for stable, long-lived charged particles at LEP energies, establishing new mass limits and cross-section constraints within the MSSM framework.

Findings

No evidence for stable charged particles was observed.

Mass limits of 82.5-89.5 GeV were set for various particles.

Cross-section upper limits ranged from 0.05 to 0.19 pb.

Abstract

A search for stable and long-lived massive particles of electric charge |Q/e| = 1 or 2/3, pair-produced in e+e- collisions at centre-of-mass energies from 130 to 183 GeV, is reported by the OPAL collaboration at LEP. No evidence for production of these particles was observed in a mass range between 45 and 89.5 GeV. Model-independent upper limits on the production cross-section between 0.05 and 0.19 pb have been derived for scalar and spin-1/2 particles with charge +/-1. Within the framework of the minimal supersymmetric model (MSSM), this implies a lower limit of 82.5 (83.5) GeV on the mass of long-lived right- (left-)handed scalar muons and scalar taus. Long-lived charged leptons and charginos are excluded for masses below 89.5 GeV. For particles with charge +/-2/3 the upper limits on the production cross-section vary between 0.05 and 0.2 pb. All limits, on masses and on cross-sections, are valid at the 95% confidence level for particles with lifetimes longer than 10^{-6} s.