Strange Baryon Production in Hadronic Z 0 Decays OPAL Collaboration

The production of the J = 1 2 + octet baryons and , the J = 3 2 + decuplet baryons (1385) , (1530) 0 , and , and the J = 3 2 orbitally excited state (1520) has been measured in a sample of approximately 3.65 million hadronic Z 0 decays. The integrated rates and the di erential cross-sections as a function of xE, the scaled energy, are determined. The di erential cross-sections of the and baryons are found to be softer than those predicted by both the JETSET and HERWIG Monte Carlo generators. The measured baryon yields are found to disagree with the simple diquark picture where only one tuning parameter for spin 1 diquarks is allowed. The yields are further compared with a thermodynamic model of hadron production which includes the production of orbitally excited mesons and baryons. The momentum spectra of , , (1385) , (1530) 0 , and (1520) are also compared to the predictions of an analytical QCD formula. (Submitted to Zeitschrift f ur Physik C) The OPAL Collaboration G.Alexander 23 , J.Allison 16 , N.Altekamp 5 , K.Ametewee 25 , K.J.Anderson 9 , S.Anderson 12 , S.Arcelli 2 , S.Asai 24 , D.Axen 29 , G.Azuelos 18;a , A.H.Ball 17 , E.Barberio 8 , R.J. Barlow 16 , R.Bartoldus 3 , J.R.Batley 5 , J. Bechtluft 14 , C.Beeston 16 , T.Behnke 8 , A.N.Bell 1 , K.W.Bell 20 , G.Bella 23 , S. Bentvelsen 8 , P.Berlich 10 , S. Bethke 14 , O.Biebel 14 , V.Blobel 8 , I.J. Bloodworth 1 , J.E.Bloomer 1 , M.Bobinski 10 , P.Bock 11 , H.M.Bosch 11 , M.Boutemeur 34 , B.T.Bouwens 12 , S. Braibant 12 , R.M.Brown 20 , H.J. Burckhart 8 , C.Burgard 8 , R.B urgin 10 , P.Capiluppi 2 , R.K.Carnegie 6 , A.A.Carter 13 , J.R.Carter 5 , C.Y.Chang 17 , C.Charlesworth 6 , D.G.Charlton 1;b , D.Chrisman 4 , S.L.Chu 4 , P.E.L.Clarke 15 , I. Cohen 23 , J.E.Conboy 15 , O.C.Cooke 16 , M.Cu ani 2 , S.Dado 22 , C.Dallapiccola 17 , G.M.Dallavalle 2 , S.De Jong 12 , L.A. del Pozo 8 , K.Desch 3 , M.S.Dixit 7 , E. do Couto e Silva 12 , M.Doucet 18 , E.Duchovni 26 , G.Duckeck 34 , I.P.Duerdoth 16 , J.E.G.Edwards 16 , P.G.Estabrooks 6 , H.G.Evans 9 , M.Evans 13 , F. Fabbri 2 , P. Fath 11 , F. Fiedler 12 , M.Fierro 2 , H.M.Fischer 3 , R. Folman 26 , D.G.Fong 17 , M.Foucher 17 , A. F urtjes 8 , P.Gagnon 7 , A.Gaidot 21 , J.W.Gary 4 , J.Gascon 18 , S.M.Gascon-Shotkin 17 , N.I.Geddes 20 , C.Geich-Gimbel 3 , F.X.Gentit 21 , T.Geralis 20 , G.Giacomelli 2 , P.Giacomelli 4 , R.Giacomelli 2 , V.Gibson 5 , W.R.Gibson 13 , D.M.Gingrich 30;a , D.Glenzinski 9 , J.Goldberg 22 , M.J.Goodrick 5 , W.Gorn 4 , C.Grandi 2 , E.Gross 26 , M.Gruw e 8 , C.Hajdu 32 , G.G.Hanson 12 , M.Hansroul 8 , M.Hapke 13 , C.K.Hargrove 7 , P.A.Hart 9 , C.Hartmann 3 , M.Hauschild 8 , C.M.Hawkes 5 , R.Hawkings 8 , R.J.Hemingway 6 , G.Herten 10 , R.D.Heuer 8 , M.D.Hildreth 8 , J.C.Hill 5 , S.J.Hillier 1 , T.Hilse 10 , P.R.Hobson 25 , R.J.Homer 1 , A.K.Honma 28;a , D.Horv ath 32;c , R.Howard 29 , R.E.Hughes-Jones 16 , D.E.Hutchcroft 5 , P. Igo-Kemenes 11 , D.C. Imrie 25 , M.R. Ingram 16 , K. Ishii 24 , A. Jawahery 17 , P.W. Je reys 20 , H. Jeremie 18 , M. Jimack 1 , A. Joly 18 , C.R. Jones 5 , G. Jones 16 , M. Jones 6 , R.W.L. Jones 8 , U. Jost 11 , P. Jovanovic 1 , T.R. Junk 8 , D.Karlen 6 , K.Kawagoe 24 , T.Kawamoto 24 , R.K.Keeler 28 , R.G.Kellogg 17 , B.W.Kennedy 20 , B.J.King 8 , J.Kirk 29 , S.Kluth 8 , T.Kobayashi 24 , M.Kobel 10 , D.S.Koetke 6 , T.P.Kokott 3 , S.Komamiya 24 , R.Kowalewski 8 , T.Kress 11 , P.Krieger 6 , J. von Krogh 11 , P.Kyberd 13 , G.D. La erty 16 , H. Lafoux 21 , R. Lahmann 17 , W.P. Lai 19 , D. Lanske 14 , J. Lauber 15 , S.R. Lautenschlager 31 , J.G. Layter 4 , D. Lazic 22 , A.M. Lee 31 , E. Lefebvre 18 , D. Lellouch 26 , J. Letts 2 , L. Levinson 26 , C. Lewis 15 , S.L. Lloyd 13 , F.K. Loebinger 16 , G.D. Long 17 , M.J. Losty 7 , J. Ludwig 10 , A. Luig 10 , A.Malik 21 , M.Mannelli 8 , S.Marcellini 2 , C.Markus 3 , A.J.Martin 13 , J.P.Martin 18 , G.Martinez 17 , T.Mashimo 24 , W.Matthews 25 , P.Mattig 3 , W.J.McDonald 30 , J.McKenna 29 , E.A.Mckigney 15 , T.J.McMahon 1 , A.I.McNab 13 , R.A.McPherson 8 , F.Meijers 8 , S.Menke 3 , F.S.Merritt 9 , H.Mes 7 , J.Meyer 27 , A.Michelini 2 , G.Mikenberg 26 , D.J.Miller 15 , R.Mir 26 , W.Mohr 10 , A.Montanari 2 , T.Mori 24 , M.Morii 24 , U.M uller 3 , K.Nagai 26 , I. Nakamura 24 , H.A.Neal 8 , B.Nellen 3 , B.Nijjhar 16 , R.Nisius 8 , S.W.O'Neale 1 , F.G.Oakham 7 , F.Odorici 2 , H.O.Ogren 12 , T.Omori 24 , M.J.Oreglia 9 , S.Orito 24 , J. P alink as 33;d , G. P asztor 32 , J.R. Pater 16 , G.N.Patrick 20 , J. Patt 10 , M.J. Pearce 1 , S. Petzold 27 , P. Pfeifenschneider 14 , J.E. Pilcher 9 , J. Pinfold 30 , D.E. Plane 8 , P. Po enberger 28 , B. Poli 2 , A. Posthaus 3 , H. Przysiezniak 30 , D.L.Rees 1 , D.Rigby 1 , S.A.Robins 13 , N.Rodning 30 , J.M.Roney 28 , A.Rooke 15 , E.Ros 8 , A.M.Rossi 2 , M.Rosvick 28 , P.Routenburg 30 , Y.Rozen 22 , K.Runge 10 , O.Runolfsson 8 , U.Ruppel 14 , D.R.Rust 12 , R.Rylko 25 , K. Sachs 10 , E.K.G. Sarkisyan 23 , M. Sasaki 24 , C. Sbarra 2 , A.D. Schaile 34 , O. Schaile 34 , F. Scharf 3 , P. Schar -Hansen 8 , P. Schenk 4 , B. Schmitt 8 , S. Schmitt 11 , M. Schroder 8 , H.C. Schultz-Coulon 10 , M. Schulz 8 , M. Schumacher 3 , P. Sch utz 3 , W.G. Scott 20 , T.G. Shears 16 , B.C. Shen 4 , C.H. Shepherd-Themistocleous 27 , P. Sherwood 15 , G.P. Siroli 2 , A. Sittler 27 , A. Skillman 15 , A. Skuja 17 , A.M. Smith 8 , T.J. Smith 28 ,