Z production cross sections and lepton pair forward-backward asymmetries

C Vannini,D Nicod,A Pacheco,B Gobbo,F Dydak,E Veitch,P Girtler,U Stiegler,A Farilla,R W Clifft,G Fouque,H Duarte,J Boucrot,H Drevermann,A Valassi,J Wotschack,W Blum,B Pietrzyk,E Blucher,W Maitland,G Lütjens,G Rudolph,A Moutoussi,F Combley,S Natali,M Carpinelli,G Triggiani,G Sanguinetti,A G Wright,S W Snow,I Ferrante,A Rougé,P Bourdon,H Dietl,G Hughes,C N Booth,B Rensch,E Simopoulou,G Bencivenni,J Lefrançois,M Bardadin-Otwinowska,R Alemany,J Schwindling,G Lutters,K Zachariadou,F Rivera,B Renk,I S Quazi,B Vallage,G Mannocchi,W Kozanecki,W Tejessy,L Passalacqua,S D Johnson,P Perrodo,J Boudreau,R Beuselinck,F Etienne,P Tempesta,G Bologna,E P Whelan,C Bozzi,J M Scarr,A Minten,R Xu,A Blondel,A Böhrer,M Davier,W Cameron,A Vayaki,F Podlyski,C Geweniger,C Markou,J Minguet-Rodriguez,F Sefkow,Y Saadi,J Raab,P Colas,J Steinberger,C Benchouk,A Roussarie,J Wear,J Knobloch,P Comas,A Antonelli,D J Candlin,F Saadi,J Grahl,A Lusiani,H Wachsmuth,G Bonvicini,J Jousset,M Rumpf,G Felici,A Cordier,J Badier,M Delfino,M Corden,J Hilgart,B Michel,P Odier,K Tittel,G Capon,P Reeves,F V Weber,G Batignani,D G Payne,A Putzer,F Fidecaro,U Becker,M Wunsch,W Männer,W T Morton,A Galla,S M Walther,O Braun,H Meinhard,F Forti,F Ariztizabal,H Videau,F Ruggieri,P Palazzi,S Adlung,M Verderi,B Bloch-Devaux,L Pitis,M Saich,M Schmelling,C Guicheney,M Pepe-Altarelli,J Rothberg,P Campana,T Ruan,D Schlatter,R Hagelberg,A Ranieri,I Lehraus,D Levinthal,F Bossi,H Seywerd,C Rankin,J K Sedgbeer,J Lauber,T Medcalf,R Settles,P Payre,U Stierlin,O Callot,D Buskulic,T Fearnley,L Bellantoni,P Perret,I Siotis,A Gregorio,I Videau,Y S Gao,S Emery,J F Hassard,W Witzeling,C Boyer,F Foster,F Ranjard,G Rizzo,G Giannini,P Colrain,A J Finch,B Jost,S Thorn,M Nuttall,G Calderini,C Bauer,W Babbage,P Henrard,G Parrini,N R Keemer,B Marx,Z Feng,P Laurelli,I G Knowles,M G Smith,J Carr,D M Binnie,M Talby,A P Betteridge,E B Martin,H Hu,M Edwards,G Selvaggi,A Messineo,J Lin,W Zhao,P R Norton,J L Harton,L Duflot,E Locci,P H Hansen,G Raso,P Spagnolo,A Venturi,A M Litke,J C Brient,G Ganis,G Iaselli,C Diaconu,R Richter,L Moneta,G Bagliesi,D Rousseau,U Bottigli,S Nuzzo,J Harvey,J D Turk,H Schmidt,I Scott,J C Montret ,M Depalma ,G R Bonneaud ,G Mäggi ,J.g Lynch ,J.m Crespo ,K C Moffeit ,E Fernández ,R.m Turnbull ,P Pérez ,Bertin ,L Foà ,F Lediberder ,C Padilla Aranda ,G Georgiopoulos ,Vivek Sharma ,O.j Hayes ,Á Pascual ,J F Pusztaszeri ,Eric O Feigl ,Gaitan ,A M Lutz ,D Si Mohand ,I Debonis ,R Stdenis ,T S Mattison ,X T Huang ,R Dellamarina ,Hepp ,A Barrès ,D Colling ,H G Moser ,P.v March ,S L Wu ,Mg Green ,G Sanmartin ,J.c Thompson ,J F Renardy ,L Zhang ,Y Pan ,D Johnson ,J.-F Grivaz ,S J Haywood ,Heussep ,P Couyle ,Pater ,M.-N Minard ,M Martı́nez ,P W Cattaneo ,Р Тенчини ,A.w Halley ,Siegmund Brandt ,T Wang ,Pedro Saraiva ,D Kühn ,M Fernández-Bosman ,D Décamp ,R.p Johnson ,E Beddall ,S L Cartwright ,Richard A Hansen ,Philippe Ghez ,B.s Nilsson ,M H Schune ,W Chen ,R Möllerud ,P Mató ,G N Taylor ,Apoorva Patel ,R Dell’orso ,J Conway ,S Orteu ,J J Veillet ,J Zhang ,L M Mir ,R Edgecock ,R.g Jacobsen ,Ph Schwemling ,J P Schuller ,D.p.s Ferguson ,J P Lees ,R Forty ,Michael G Schmidt ,Botterill ,L Smolík ,H G Sander ,G Rolandi ,Kim Dw ,D N Brown ,K M Smith ,I Tenhave ,G Lütz ,F Romanò ,L.f Thompson ,M A Ciocci,A Bonissent,B Dehning,F Cerutti,M A Giorgi,J Rander,I R Tomalin,I Dawson,F Palla,M Cattaneo,L Silvestris,R Veenhof,R Wanke,A M Greene,M Maggi,F Ligabue,M Frank,G Zobernig,D Calvet,D Abbaneo,C Goy,J Schröder,D Pallin,G Cowan,A M Walsh,E Focardi,V Chiarella,A S Thompson,P S Marrocchesi,X Wu,J R Hansen,D Xu,H Stenzel,P J Dornan,C K Bowdery,S Wasserbaech,A Kyriakis,Z Ajaltouni,J A Perlas,J Proriol,J M Yamartino,K Jakobs,M Girone,M C Lemaire,Ll Garrido,P Hanke,D Casper,M Schmitt,G Zito,J D Hansen,R Vogl,C Grupen,M Zheng,P Janot,D Jackson,D Creanza,V Ciulli,A Rosowsky,D Huang,P G Verdini,T Sloan,D E Jaffe,A Falvard,A Giassi,J A Strong,K Kleinknecht,B Wolf,U Schäfer,E E Kluge,J Nash,G Tonelli,E Lançon,R Assmann,N Konstantinidis,G Wolf,R Miquel,A S Schwarz,I Efthymiopoulos,J M Nachtman,G Musolino,Y Chai,N Marinelli,T Wildish,J Walsh,W Wiedenmann,Y Xie,M I Parsons,A M Bencheikh,R Tanaka,C Raine,T J Brodbeck,F Murtas,L Roos,F Ragusa,S Salomone

doi:10.1007/bf01574159

Abstract

Precise values of theZ resonance cross sections and lepton pair forward-backward asymmetries are measured from a sample of 1.3 millionZ decays into hadrons and charged leptons taken with the ALEPH detector at LEP. A silicon-tungsten luminosity calorimeter was installed in ALEPH in 1992, permitting the determination of the absolute luminosity to a systematic precision of 0.15% (experimental) and 0.25% (theoretical). This is combined with a better understanding of the hadronic event selection and an improved tau pair selection. Including the ALEPH results of the past three years one obtains σ 0 h =(41.60±0.16) nb, andR l =20.69±0.09. The corresponding number of light neutrino species isN v =2.983±0.034. The lepton pair forward-backward asymmetry is used to derive the ratio of vector to axial-vector couplings of leptons:g 2 V (M 2 Z )/g 2 A (M 2 Z )=0.0058 ±0.0011. An application of these results to constrain one model with extraZ bosons is presented.

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