Title Search for Dirac magnetic monopoles in $e^{+}e^{-}$ collisions with the OPAL detector at LEP2 Author Abbiendi, G. De Roeck, A. de Wolf, E.A. et al. Faculty/Department Faculty of Sciences. Physics Publication type article Publication 2008 Amsterdam , 2008 Subject Physics Source (journal) Physics letters: B. - Amsterdam, 1967, currens Volume/pages 663(2008) :1/2 , p. 37-42 ISSN 0370-2693 ISI 000256744300007 Carrier E Target language English (eng) Full text (Publishers DOI) Affiliation University of Antwerp 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 . 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 (ó) in the mass range 45 GeV/c2