A study of charged particle multiplicities in hadronic decays of theZ 0

P W Jeffreys,P M Hattersley,G A Snow,G Bella,S Orito,S Tarem,M Jimack,F Meijers,H Ihssen,A M Smith,R J Hemingway,V Gibson,P Leblanc,G Giacomelli,J Letts,P Taras,P Lennert,R D Heuer,P R Hobson,H Oh,C Kleinwort,P Capiluppi,S Komamiya,W Schappert,S Schreiber,T J Smith,C J Oram,P Ashton,E Ros,G Maringer,F S Merritt,S J Hillier,M Mannelli,G Azuelos,M Fincke-Keeler,J Allison,D Robinson,A Gaidot,R Humbert,C K Hargrove,G T Zorn,G Eckerlin,A Pouladdej,J G Layter,M Ogg,R M Brown,P Sherwood,J Banks,R Mir,H Przysiezniak,J P Martin,B Poli,G Yekutieli,P S Wells,P Teixeira-Dias,S Bethke,R Brun,J Schwiening,A Simon,D L Rees,R P Middleton,M S Dixit,P Weber,P Kyberd,D E Plane,W G Scott,R F Mcgowan,S Levegrün,S Sanghera,S Dado,J E Conboy,M Sproston,S Rossberg,P P Allport,N C Wood,T Kobayashi,J E Pilcher,D Hochman,D Menszner,T P Kokott,G J Barker,B W Kennedy,G M Dallavalle,S L Lloyd,T J Mcmahon,F C Grant,A M Lee,F G Oakham,H Breuker,J Gascon,G Vasseur,M H Lehto,R Shypit,M Kuwano,M Jobes,M Yurko,R Kowalewski,M Weber,J Goldberg,I P Duerdoth,H O Ogren,P Scharff-Hansen,S Marcellini,G Tysarczyk-Niemeyer,R K Carnegie,P Bock,J C Hill,M Settles,A K Honma,T Kawamoto,S Bougerolle,D Strom,F X Gentit,U Binder,J Becker,S Weisz,C P Howarth,E Etzion,M Cuffiani,B P O'Neill,A T Watson,P A Elcombe,T R Wyatt,P Pfister,T W Pritchard,H M Bosch,C Wahl,A Skuja,H Mes,M W Redmond,R J Homer,J D Gillies,J Kroll,G Duckeck,G N Patrick,M J Oreglia,J M Lorah,P G Estabrooks,K J Anderson,U Maur,K Stephens,R Yaari,G A Bahan,G D Lafferty,G Beaudoin,S Arcelli,F Odorici,C Moisan,B C Shen,A Astbury,P Debu,K Kawagoe,M Nozaki,E Prebys,K Riles,H E Stier,I J Bloodworth,C Fukunaga,P Berlich,C J Virtue,D Pitman,R W Springer,D Lellouch,A D Schaile,M J Losty,G J Vandalen,D A Hinshaw,K W Bell,M A Whalley,D R Ward,A H Ball,D J Miller,I Zacharov,P Paschievici,W Mohr,J Mildenberger,P D Acton,N K Watson,A C Janissen,O Biebel,C Grandi,R G Kellogg,H M Fischer,P F Harrison,D G Fong,A Rollnik,M Cooper,J M Roney,A A Carter,R Ströhmer,A Beck,P Singh,H Kreutzmann,O Ganel,H H Nguyen,W J Larson,A Buijs,J W Gary,D C Imrie,G W Wilson,G P Siroli,T Takeshita,D E Klem,M Weymann,O Schaile,J R Mcnutt,C Y Chang,J P Walker,C Ho,D Karlen,G Alexander,W R Gibson,J P Pansart,A Jawahery,C M Hawkes,B Nellen,A Michelini,T Mouthuy,E Duchovni,J R Carter,P Schenk,F K Loebinger,J A Wilson,M W Moss,P Mättig,M Sasaki,C Leroy,M Dittmar,P Routenburg,D Axen,B Panzer-Steindel,B Lorazo,P M Watkins,J Hagemann,I Cohen,L Köpke,P Poffenberger,M Hansroul,A Dieckmann,G Mikenberg,B Holl,J Ludwig,J R Batley,D R Rust,N J Thackray,S J Pawley,R J Barlow,N I Geddes,T Mori,M J Goodrick,A Wagner,M Hauschild,G Quast,A M Rossi,B Boden,T Behnke,A Montanari,N Wermes,R E Hughes-Jones,M Couch,J L Pinfold,M Coupland,C P Ward,F Lamarche,S A Robins,M Rosvick,W J Collins,S W Gensler,F Fabbri,K Runge,E Heflin,D G Charlton,W Gorn,L A Del Pozo ,G Tranströmer ,X Lou ,S Hou ,S W O’neale ,H Jérémie ,B Brabson ,J Král ,P Igo‐Kemenes ,P E.l Clarke ,P Jovanović ,J Hobbs ,T Mäshimo ,D J.p Dumas ,Yifan Yang ,S A Wotton ,J Von Krogh ,W D Zeuner ,P Le Dû ,H Burckhart ,R J Sobie ,Hiroshi Takeda ,G Hanson ,M Turner ,Roger Jones ,Haruka Tsukamoto ,Ch Geich-Gimbel ,Ö Runólfsson ,Isabelle Wingerter ,L J Levinson ,A Martín ,D Van Den Plas ,V H Winterer ,R Keeler ,J T Baines ,R Van Kooten ,S J De Jong ,J A Mckenna ,M Deninno ,J C Hart ,H Von Der Schmitt

doi:10.1007/bf01559731

Abstract

We present an analysis of multiplicity distributions of charged particles produced inZ 0 hadronic decays. The results are based on the analysis of 82941 events collected within 100 MeV of theZ 0 peak energy with the OPAL detector at LEP. The charged particle multiplicity distribution, corrected for initial-state radiation and for detector acceptance and resolution, was found to have a mean 〈n ch〉=21.40±0.02(stat.)±0.43(syst.) and a dispersionD=6.49±0.02(stat.)±0.20(syst.). The shape is well described by the Lognormal and Gamma distributions. A negative binomial parameterisation was found to describe the shape of the multiplicity distribution less well. A comparison with results obtained at lower energies confirms the validity of KNO(-G) scaling up to LEP energies. A separate analysis of events with low sphericity, typically associated with two-jet final states, shows the presence of features expected for models based on a stochastic production mechanism for particles. In all cases, the features observed in the data are well described by the Lund parton shower model JETSET.

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