Search for Direc Magnetic Monopoles in e+e- Collisions with the OPAL Detector at LEP2

TL;DR

This study conducted a direct search for magnetic monopoles in electron-positron collisions at LEP2 using the OPAL detector, setting upper limits on monopole production cross-section without observing any monopoles.

Contribution

First direct search for magnetic monopoles in e+e- collisions at LEP2 with new upper limits on production cross-section for monopoles.

Findings

No evidence of magnetic monopole production was observed.

Set upper limits on monopole pair-production cross-section at 95% confidence level.

Limits are valid for monopoles with masses between 45 and 102 GeV/c^2.

Abstract

This letter describes a direct search for pair produced magnetic monopoles in e+e- collisions. The analysis is based on 62.7 pb^-1 of data collected with the OPAL detector at an average centre-of-mass energy of sqrt(s)= 206.3GeV. The monopole signal was assumed to be characterized by two back-to-back particles with an anomalously high ionization energy loss de/dx in the tracking chambers. No evidence for production of monopoles was observed. Upper limits were obtained on the magnetic monopole pair-production cross-section (sigma) in the mass range 45 GeV/c^2<m_M<102 GeV/c^2. The average limit is sigma < 0.05 pb and is essentially independent of the magnetic monopole mass. The cross-section limit is derived at the 95% confidence level and is valid for spin-1/2 magnetic monopoles.