Search for single top production at LEP

P Achard,B Tellili,S Falciano,A Mihul,D Teyssier,P Raics,G Landi,S Riemann,P Wienemann,M Kaur,J Allaby,F Filthaut,H Rykaczewski,N Shivarov,B Zimmermann,G Rahal-Callot,S Schmidt-Kaerst,T Ferguson,Z.M Wang,M Wadhwa,N Batalova,A Sakharov,F Cindolo,S Sushkov,B Musicar,W Krenz,M Vivargent,K Mazumdar,F Pierella,L Tauscher,M Dierckxsens,M Rescigno,P Bagnaia,L Malgeri,Yu Galaktionov,A Chen,G Coignet,A Zichichi,C Rosenbleck,M Gataullin,H Vogel,S Wynhoff,L Baksay,G Grenier,S Sarkar,P.G Rancoita,G Schwering,P Lecoq,G Vesztergombi,R Clare,A Eline,F Behner,W Wallraff,D Pandoulas,L Merola,S Banerjee,E Delmeire,G Passaleva,M Hohlmann,A Favara,L Lista,P Lecomte,K Dehmelt,A Bajo,G Carlino,M Chemarin,S Saremi,A Gurtu,B Borgia,X.L Wang,B Stoyanov,E Fiandrini,K Deiters,S Cucciarelli,U Becker,C Timmermans,V Koutsenko,T Paul,F Denotaristefani,A Biland,Y.S Lu,H Hofer,W.G Ma,M Pauluzzi,L Cifarelli,C Palomares,A Straessner,P Levtchenko,G Sultanov,G Alemanni,E Longo,L Romero,M Biglietti,M Levtchenko,W Fisher,J Berdugo,E Shumilov,T Hebbeker,G Chiefari,R Battiston,D Vicinanza,G Viertel,I Fisk,G Holzner,O Grimm,R Ranieri,S Shevchenko,Yu Zalite,G Organtini,S Vlachos,S Bottai,Z.A Liu,A Barczyk,O Adriani,D Prokofiev,M Meschini,N Raja,H.F Chen,M Pedace,B Echenard,A Raspereza,L Servoli,R Berbeco,M Dittmar,H Fesefeldt,M Pohl,C Schäfer,R Ramelli,P Déglon,M Napolitano,V Plyaskin,T Azemoon,D Hatzifotiadou,M Steuer,K Sudhakar,A Bay,C Dionisi,I Vetlitsky,J Pothier,C Souga,A Krüger,M Cerrada,A Arefiev,A Degré,H Milcent,S Patricelli,K Riles,F Marzano,D Duchesneau,C Tully,A Rosca,M Bourquin,I Vodopianov,B Roux,H Suter,V Pojidaev,J Ulbricht,W Lustermann,S Costantini,H Vogt,J Hirschfelder,D Bourilkov,M Basile,J Tóth,N Cavallo,F Anselmo,B.L Betev,J Quartieri,M Lebeau,G.M Chen,N Colino,A Böhm,D Käfer,F.L Linde,D Schmitz,T Siedenburg,J Fay,W Lohmann,J Alcaraz,M Capell,D Ren,M Musy,S Giagu,I Vorobiev,V Shoutko,S Braccini,I Clare,A Engler,S Gentile,L Xia,M Chamizo,J Kirkby,R Leiste,P Paolucci,S Pensotti,C Luci,C Furetta,M Diemoz,H.S Chen,P Lebrun,S Mele,E Valente,C Li,A Kunin,D Mangeol,A Klimentov,H Anderhub,F Becattini,R Paramatti,F Cavallari,L Luminari,K Freudenreich,A Shvorob,L Taylor,W Kittel,S.V Baldew,R Barillère,C Cecchi,S Nagy,H.L Zhuang,M Felcini,P Berges,J Yamamoto,D Perret-Gallix,H Nowak,J Mnich,D Haas,Samuel C.C Ting,A Aloisio,G Mirabelli,J Casaus,H Schopper,Z.P Zhang,J Debreczeni,M Kräber,D Piccolo,P Extermann,Y Hu,A Hervé,C Sciacca,A Doria,K Lübelsmeyer,J Mans,E Pistolesi,B Bertucci,M Guida,G Baksay,S Reucroft,G Ruggiero,J Salicio,A Nisati,C Paus,A Ewers,S Villa,S Likhoded,T Aziz,P Denes,I Josa-Mutuberrı́A,P Bartalini,A Lebedev,G Chen,M Biasini,J.K Kim,R.W Kraemer,S.N Ganguli,L Bellucci,B Z Yang ,G Cara Romeo ,H B Newman ,A Zalite ,I B Laktineh ,P H Fisher ,D Della Volpe ,R Hakobyan ,Z Xu ,J D Swain ,P Piroué ,R R Mcneil ,J P Martín ,M P Sanders ,M Pioppí ,Yu-Hsiang Chang ,B N Jin ,R Y Zhu ,M A Rahaman ,Junjie Zhao ,L Boldizsár ,J J Blaising ,P De Jong ,R T Van De Walle ,R Van Gulik ,V Andreev ,Z Szillási ,T Nießen ,H J Yang ,A C König ,Stefan Roth ,M W Gruenewald ,W Lin ,C Mañá ,R De Asmundis ,П Спиллантини ,A J.m Muijs ,Min Yang ,D Stickland ,Sonia Natale ,W J Burger ,J H Field ,J G Branson ,S Hou ,M G Alviggi ,P Garcı́a-Abia ,G J Bobbink ,Raymond Vasquez ,K L Tung ,F Nessi‐Tedaldi ,G Y Zhu ,P A Razis ,V A Schegelsky ,А Малинин ,D C Son ,J A Rubio ,F Pauß ,M T Dova ,G Forconì ,A A Vorobyov ,F M Brochu ,P Tarján ,O L Fedin ,S Blyth ,J D Burger ,Martin Weber ,F J Eppling ,J A Van Dalen ,V Veszprémi ,P Ladrón De Guevara ,R A Ofierzynski ,E Sánchez ,C H Lin ,S C Yeh ,B P Roe ,M A Falagán ,L Gutay ,H El Mamouni ,P Le Coultre ,D J Schotanus ,X Cai ,S C Tonwar ,L W Jones ,G B Mohanty ,M Aguilar-Benı́tez ,G S Muanza ,W J Metzger ,M N Kienzle‐Focacci ,V K Gupta ,J M Le Goff ,B De La Cruz ,M Kopál ,A M Cartacci ,Z F Gong ,S Rosier‐Lees ,A De Salvo ,H G Wilkens ,S M Ting ,B A Petersen ,L Z Sun ,X W Tang ,C G Yang ,Margot Zöller

doi:10.1016/s0370-2693(02)02933-7

Abstract

Single top production in e+e− annihilations is searched for in data collected by the L3 detector at centre-of-mass energies from 189 to 209 GeV, corresponding to a total integrated luminosity of 634 pb−1. Investigating hadronic and semileptonic top decays, no evidence of single top production at LEP is obtained and upper limits on the single top cross section as a function of the centre-of-mass energy are derived. Limits on possible anomalous couplings, as well as on the scale of contact interactions responsible for single top production are determined.

Highlights

One of the fundamental features of the Standard Model is that neutral currents are flavour diagonal, any flavour changing neutral current (FCNC) process may occur only at second or higher orders through loops
The FCNC interactions of the top quark offer an ideal place to search for new physics and can be studied either in t → qV (q = u, c; V = γ, Z) decays at the Tevatron or in single top production at LEP
In the Standard Model, the predicted rates of such processes are very small [1], but new physics beyond the Standard Model could lead to a significant increase

Summary

Introduction

One of the fundamental features of the Standard Model is that neutral currents are flavour diagonal, any flavour changing neutral current (FCNC) process may occur only at second or higher orders through loops. In this Letter, we consider two theoretical models for single top production e+e− → tc 1): an interpretation involving [tce+e−] contact interactions and an approach which describes the process in terms of anomalous couplings.

Results

Conclusion