Improved study of the structure ofe+e−→bb¯gevents and limits on the anomalous chromomagnetic coupling of thebquark

K Abe ,J P Fernandez,V Eschenburg,T H Burnett,T Schalk,D Falciai,R Messner,M Piccolo,E Torrence,S Manly,S Walston,H Yuta,I Erofeeva,S Fahey,J Va’Vra,A Suzuki,M Woods,J A Jaros,T Abe,V Lia,A P Waite,M Morii,R Frey,R Verdier,H R Band,S Narita,H O Cohn,N Oishi,H Akimoto,A W Weidemann,X Huynh,O H Saxton,D Su,M Iwasaki,A Calcaterra,G Mancinelli,R Prepost,M Kalelkar,P C Rowson,S Willocq,J M Bauer,S S Hertzbach,N De Groot,Kenji Abe,B N Ratcliff,D Onoprienko,K Hasuko,J Schwiening,L Piemontese,J E Brau,F Suekane,V Cook,G Blaylock,D Aston,R Kajikawa,G Crawford,U Nauenberg,H Staengle,G Nesom,W J Wisniewski,M Daoudi,A Chou,C C Young,G Bellodi,T B Moore,C Baltay,N B Sinev,R Dubois,M R Convery,R K Yamamoto,R De Sangro,E L Hart,J Yashima,T Maruyama,A Sugiyama,M Langston,P L Reinertsen,C Lin,J Reidy,J R Bogart,T Barklow ,L.s Rochester ,Robert S Wilson ,L S Osborne,B A Schumm,J Wittlin ,Robert Berger ,H J Kang,J Thom,K Baird ,E R Weiss,R Kofler ,Z Jiang ,T Usher,T W Markiewicz,D L Wagner,C H Park,V.v Serbo ,D Jackson ,P.n Burrows ,R Cowan ,T Wright ,W Bugg ,R J Plano,V S Murzin ,E Etzion,A Stahl,M Doser,J R Johnson,R.s Panvini ,K C Moffeit,M Breidenbach,H Steiner,R Cassell,P Jacques,M Swartz,И Адам ,G Mantovani,J S Whitaker,P Stamer,J A Coller,M.e Huffer ,A K Mckemey,D R Müller ,D.w.g.s Leith ,A Johnson ,I Peruzzi,G Shapiro,C Y Prescott,J J Russell,S Yellin ,G R Bower,R Kroeger ,Chris Damerell ,H Neal,K T Flood ,D L Burke ,D Dong ,F Taylor ,J A Snyder,S Williams

doi:10.1103/physrevd.66.052001

Abstract

The structure of three-jet e{sup +}e{sup -} {yields} b{bar b}g events has been studied using hadronic Z{sup 0} decays recorded in the SLD experiment at SLAC. Three-jet final states were selected and the CCD-based vertex detector was used to identify two of the jets as b or {bar b}; the remaining jet in each event was tagged as the gluon jet. Distributions of the gluon energy and polar angle with respect to the electron beam were measured over the full kinematic range, and used to test the predictions of perturbative QCD. We find that beyond-leading-order QCD calculations are needed to reproduce the features seen in the data. The energy distribution is sensitive to an anomalous b chromomagnetic moment {kappa} at the b{bar b}g vertex. We measured {kappa} to be consistent with zero and set 95% C.L. limits on its value, -0.06 < {kappa} < 0.04.

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