Improved Measurement of the Left-RightZ0Cross Section Asymmetry

Abe K ,M J Fero,J Quigley,E R Weiss,J A Snyder,K C Moffeit,S S Hertzbach,A K Mckemey,R Kajikawa,R Frey,H Yuta,H Neal,H Hwang,H Steiner,A I Trandafir,W Busza,G Crawford,J Ma,S Sen,B Camanzi,R De Sangro,S Narita,I Peruzzi,G L Bashindzhagyan,D L Wagner,T B Moore,T Maruyama,R Verdier,I Karliner,M Nussbaum,H Park,D Falciai,G Shapiro,G Blaylock,A P Waite,D Su,K Hasuko,E Pieroni,G B Word,M Daoudi,G Gladding,R Cassell,R H Schindler,R A Johnson,A Calcaterra,R S Panvini,J T Shank,R J Plano,P G Verdini,D A Williams,H R Band,E Mazzucato,T W Reeves,U Nauenberg,T Usher,R Prepost,C Y Prescott,M Loreti,M X Liu,S R Smith,C Vannini,J Wyss,B A Schumm,T W Markiewicz,J P Venuti,J M Yamartino,Y Hasegawa,L S Osborne,J Huber,G Zapalac,G R Bower,C Simopoulos,E Church,M Langston,D G Coyne,H Kawahara,X Liu,G D Punkar,E W Hughes,N B Sinev,P Jacques,F J Wickens,W J Wisniewski,R Steiner,C Baltay,M Breidenbach,V Lia,A Lath,C C Young,D Bisello,J L Harton,G Mancinelli,R Dubois,P Stamer,K Furuno,M G Strauss,W W Ash,B I Eisenstein,Y Ohnishi,P L Reinertsen,D W G S Leith,J Reidy,A Szumilo,T H Burnett,F Suekane,J F Labs,S L White,J S Whitaker,P C Rowson,R Messner,E Vella,T Akagi,A Chou,A Hasan,E Torrence,A Sugiyama,K Reeves,M Swartz,J J Russell,M B Barakat,L Piemontese,S Willocq,M Dima,S Suzuki,J A Jaros,Y Iwasaki,J D Turk,M Woods,A Castro,O Bardon,C Fan,J E Brau,O H Saxton,D Aston,R Cotton,M Piccolo,A C Benvenuti,D O Caldwell,A W Weidemann,T Gillman,J R Bogart,B N Ratcliff,J R Johnson,T Bolton,G Mantovani,E L Hart,S Manly,R Castaldi,M Kalelkar,H O Cohn,Y D Kim,G Baranko,R W Zdarko,R Elia,A Lu,T Schalk,G M Bilei,I Abt,C H Park,S Fahey,E Etzion,V Cook,G D Hallewell,H L Lynch,D J Sherden,S R Wagner,M Carpinelli,J Schwiening,J A Coller,R K Yamamoto,T Nagamine,D Calloway,A D’oliveira ,P.y.c Du ,A.o Bazarko ,Hyejoo Kang ,K Shmakov ,K Baird ,H.w Kendall ,D.c Williams ,D R Müller ,P.n Burrows ,A Johnson ,R Kofler ,P Mockett ,P Rensing ,S Williams ,R Wilson ,Ximeng Yang ,T Barklow ,M Smy ,Hiroaki Masuda ,J Lauber ,F Taylor ,S González ,C Damerell ,R Kroeger ,V.v Serbo ,N.j Allen ,Tohru Takahashi ,D L Burke ,R S B King ,M King ,S Watts ,W Bugg ,M Cavalli‐Sforza ,R Cowan ,M Hildreth ,S Hedges ,D Dong ,T Pavel ,P Dervan ,Brett Bolen ,S Yellin ,M.e Huffer ,N.m Krishna ,M.h Shaevitz ,B Meadows ,J Va’vra ,K Pitts ,R Ben‐David ,R Dell’orso ,T R Junk ,D Jackson ,L.s Rochester ,Jianfeng Zhou

doi:10.1103/physrevlett.78.2075

Abstract

We present a new measurement of the left-right cross section asymmetry (ALR) for Z boson production by e+e- collisions. The measurement was performed at a center-of-mass energy of 91.28 GeV with the SLD detector at the SLAC Linear Collider (SLC). The luminosity-weighted average polarization of the SLC electron beam was (77.23+-0.52)%. Using a sample of 93,644 Z decays, we measure the pole-value of the asymmetry, ALR0, to be 0.1512+-0.0042(stat.)+-0.0011(syst.) which is equivalent to an effective weak mixing angle of sin**2(theta_eff)=0.23100+-0.00054(stat.)+-0.00014(syst.).

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