Search for Leptoquarks and FCNC in e+e− annihilations at [formula omitted] GeV

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Fanourakis,B King,H M Blom ,P Gonçalves ,U Amaldi,T Rovelli,A Vodopyanov ,Th D Papadopoulou ,H B Crawley ,I A Tyapkin ,E Migliore,N Mastroyiannopoulos,J H Cowell ,U Parzefall,J Heuser ,M Sannino,D Holthuizen,Šárka Todorova ,J Krstić ,A L Read ,C Stănescu ,I Gil,M Winter,J Loken ,E Križnič ,R Keränen ,G Wilkinson ,M E Pol ,Ph Gris ,E I Rosenberg ,G Hughes ,C Kourkoumelis,N I Zimin ,F J Harris ,F R Cavallo ,E Higón ,J Wickens ,E Vlasov,J R Mahon ,Α Μάρκου ,J I Yi ,G C Zucchelli ,S Amato,O Kouznetsov,C Weiser,P Renton ,M Besançon ,L Lyons,R C Shellard ,W Mitaroff ,W Kucewicz,F Barão ,G D Alekseev ,M Esṕırito Santo ,T Allmendinger,M Lokajı́ček ,G J Barker ,M Günther ,A B Fenyuk ,S Stanič ,P Chliapnikov,R Mureşan ,E Ferrer‐Ribas ,C Troncon,I R Boyko ,E Anassontzis ,G W Van Apeldoorn ,A N Sisakian ,I Božović ,M A E Schyns ,P Chochula,F Parodi,F L Navarria ,D Z Toet ,K H Becks ,N N Khovanski ,J P Laugier ,G Jarlskog,M Krammer,B Maréchal ,C Martínez-Rivero ,J M Brunet ,T B Skaali ,C Jarlskog ,F Martínez-Vidal ,P Jönsson ,R Frühwirth ,K Österberg ,N Smirnov,N J Kjaer ,J J Hernández ,J Hrubec,G P Gopal ,C Royon ,C Petridou,P P Allport ,P Beillière ,J Řídký ,G Gómez-Ceballos ,S O Holmgren ,J Fuster,M Elsing,Daniel Bertrand ,J C Marin ,T Adye,M Mulders,J H Lopes ,A Leisos,M A Bizouard ,C Bérat ,Kathy Huet ,P Checchia,M Boonekamp,J P Thomas ,A G Olshevski ,M Górski ,G Chelkov ,D Blöch ,S Navas,H J Grimm ,P J Holt ,M V Castillo Gimenez ,D Gelé ,R López-Fernández ,B Jean‐Marie ,T G M Malmgren ,O Passon,J Lämsä ,T L Hessing ,R Brenner ,B S Nielsen ,A Ouraou,H T Phillips ,O Røhne ,K Nawrocki,M Pegoraro,M S Bilenky ,S Marti-Garcia ,J Lemonne,S Andringa,M L Turluer ,J D Durand ,P Zalewski,Xavier Moreau ,W K Van Doninck ,T Ekelöf ,A Hallgren,P Adžić ,C F Vollmer ,O Botner,M Calvi,W Vénus ,W D Apel ,U Muêller ,N Redaelli

doi:10.1016/s0370-2693(98)01525-1

Abstract

A search for events with one jet and at most one isolated lepton used data taken at LEP-2 by the DELPHI detector. These data were accumulated at a center-of-mass energy of 183 GeV and correspond to an integrated luminosity of 47.7 pb −1. Production of single scalar and vector leptoquarks was searched for. Limits at 95% confidence level were derived on the masses (ranging from 134 GeV/c 2 to 171 GeV/c 2 for electromagnetic type couplings) and couplings of the leptoquark states. A search for top-charm flavour changing neutral currents ( e +e −→ t ̄ c or charge conjugate) used the semileptonic decay channel. A limit on the flavour changing cross-section via neutral currents was set at 0.55pb (95% confidence level).

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