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Production of strange B-baryons decaying into Ξ∓-ℓ∓ pairs at LEP

Zeitschrift für Physik C Particles and Fields 68:4 (1995) 541-553

Authors:

P Abreu, W Adam, T Adye, E Agasi, I Ajinenko, R Aleksan, GD Alekseev, PP Allport, S Almehed, FML Almeida, SJ Alvsvaag, U Amaldi, S Amato, A Andreazza, ML Andrieux, P Antilogus, WD Apel, Y Arnoud, B Åsman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, R Barate, G Barbiellini, DY Bardin, GJ Barker, A Baroncelli, O Barring, JA Barrio, W Bartl, MJ Bates, M Battaglia, M Baubillier, J Baudot, KH Becks, M Begalli, P Beilliere, Y Belokopytov, P Beltran, AC Benvenuti, M Berggren, D Bertrand, F Bianchi, M Bigi, MS Bilenky, P Billoir, J Bjarne, D Bloch, M Blume, S Blyth, V Bocci, T Bolognese, M Bonesini, W Bonivento, PSL Booth, G Borisov, C Bosio, B Bostjancic, S Bosworth, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, M Bozzo, P Branchini, KD Brand, RA Brenner, C Bricman, L Brillault, RCA Brown, P Bruckman, JM Brunet, L Bugge, T Buran, A Buys, M Caccia, M Calvi, AJ Camacho Rozas, T Camporesi, V Canale, M Canepa, K Cankocak, F Cao, F Carena, P Carrilho, L Carroll, C Caso, V Cassio, MV Castillo Gimenez, A Cattai, FR Cavallo, L Cerrito, V Chabaud, M Chapkin, P Charpentier, L Chaussard, J Chauveau

Abstract:

An excess of events containing, in a jet, a samesign Ξ∓-ℓ∓ pair as compared to those with an oppositesign Ξ∓-ℓ± pair has been observed in an analysis of 1.7 million hadronic Z0 decays collected by the DELPHI detector at LEP between 1991 and 1993 inclusive. The probability for this signal to come from non B-baryon decays is less than 5×10-4. The measured production fraction corresponds to:[Figure not available: see fulltext.] per lepton species, averaged for electrons and muons and assuming that the two channels have an equal contribution. Semileptonic decays of Λb baryons can account for less than 10% of these events and the major part of the signal has to originate from Ξb semileptonic decays. Using the subsample of these events where the Ξ∓ trajectory has been measured in the Vertex Detector, the lifetime of B-baryons producing a Ξ∓ in their semileptonic decay final state is found to be: {Mathematical expression} © 1995 Springer-Verlag.
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Strange baryon production in Z hadronic decays

Zeitschrift für Physik C Particles and Fields 67:4 (1995) 543-553

Authors:

P Abreu, W Adam, T Adye, E Agasi, I Ajinenko, R Aleksan, GD Alekseev, PP Allport, S Almehed, SJ Alvsvaag, U Amaldi, S Amato, A Andreazza, ML Andrieux, P Antilogus, V Anykeyev, WD Apel, Y Arnoud, B Åsman, JE Augustin, A Augustinus, P Baillon, P Bambade, R Barate, DY Bardin, GJ Barker, A Baroncelli, O Barring, JA Barrio, W Bartl, MJ Bates, M Battaglia, M Baubillier, J Baudot, KH Becks, M Begalli, P Beilliere, Y Belokopytov, AC Benvenuti, M Berggren, D Bertrand, F Bianchi, M Bigi, MS Bilenky, P Billoir, D Bloch, M Blume, S Blyth, V Bocci, T Bolognese, M Bonesini, W Bonivento, PSL Booth, G Borisov, C Bosio, S Bosworth, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, M Bozzo, P Branchini, KD Brand, RA Brenner, C Bricman, L Brillault, RCA Brown, P Bruckman, JM Brunet, L Bugge, T Buran, A Buys, M Caccia, M Calvi, AJ Camacho Rozas, T Camporesi, V Canale, M Canepa, K Cankocak, F Cao, F Carena, P Carrilho, L Carroll, C Caso, V Cassio, MV Castillo Gimenez, A Cattai, FR Cavallo, L Cerrito, V Chabaud, P Charpentier, L Chaussard, J Chauveau, P Checchia, GA Chelkov, P Chliapnikov, P Chochula, V Chorowicz, V Cindro

Abstract:

A study of the production of strange octet and decuplet baryons in hadronic decays of the Z recorded by the DELPHI detector at LEP is presented. This includes the first measurement of the ∑± average multiplicity. The total and differential cross sections, the event topology and the baryon-antibaryon correlations are compared with current hadronization models. © 1995 Springer-Verlag.
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Study of prompt photon production in hadronic Z 0 decays

Zeitschrift für Physik C: Particles and Fields 69:1 (1995) 1-13

Authors:

P Abreu, W Adam, T Adye, E Agasi, I Ajinenko, R Aleksan, GD Alekseev, PP Allport, S Almehed, SJ Alvsvaag, U Amaldi, S Amato, A Andreazza, ML Andrieux, P Antilogus, WD Apel, Y Arnoud, B Åsman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, R Barate, G Barbiellini, DY Bardin, GJ Barker, A Baroncelli, O Barring, JA Barrio, W Bartl, MJ Bates, M Battaglia, M Baubillier, J Baudot, KH Becks, M Begalli, P Beilliere, Y Belokopytov, AC Benvenuti, M Berggren, D Bertrand, F Bianchi, M Bigi, MS Bilenky, P Billoir, D Bloch, M Blume, S Blyth, V Bocci, T Bolognese, M Bonesini, W Bonivento, PSL Booth, G Borisov, C Bosio, S Bosworth, O Botner, B Bouquet, C Bourdarios, TJV Bowcock, M Bozzo, P Branchini, KD Brand, T Brenke, RA Brenner, C Bricman, L Brillault, RCA Brown, P Bruckman, JM Brunet, L Bugge, T Buran, T Burgsmueller, P Buschmann, A Buys, M Caccia, M Calvi, AJ Camacho Rozas, T Camporesi, V Canale, M Canepa, K Cankocak, F Cao, F Carena, P Carrilho, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, L Cerrito, V Chabaud, P Charpentier, L Chaussard, J Chauveau, P Checchia, GA Chelkov, R Chierici, P Chliapnikov

Abstract:

From a sample of 1.5 million Z 0→qq decays collected by the DELPHI detector during 1991, 1992 and 1993, the production cross section for isolated final state photons is measured and is compared with the O(α, α s) matrix element calculations implemented in the EEPRAD and GNJETS Monte Carlo generators. The observed photon yield is used to derive the electroweak couplings of charge 2/3 (u-type) and charge 1/3 (d-type) quarks to the Z 0 boson. The measured values c 2/3=0.91 -0.36 +0.25 and c 1/3=1.62 -0.17 +0.24 are compatible with the Standard Model prediction, c 2/3=1.145 and c 1/3=1.477. © 1996 Springer-Verlag.
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Search for promptly produced heavy quarkonium states in hadronic Z decays

Zeitschrift für Physik C Particles and Fields Springer Nature 69:1 (1995) 575-583

Authors:

P Abreu, W Adam, T Adye, E Agasi, I Ajinenko, R Aleksan, GD Alekseev, PP Allport, S Almehed, SJ Alvsvaag, U Amaldi, S Amato, A Andreazza, ML Andrieux, P Antilogus, W-D Apel, Y Arnoud, B Åsman, J-E Augustin, A Augustinus, P Baillon, P Bambade, F Barao, R Barate, G Barbiellini, DY Bardin, GJ Barker, A Baroncelli, O Barring, JA Barrio, W Bartl, MJ Bates, M Battaglia, M Baubillier, J Baudot, K-H Becks, M Begalli, P Beilliere, Yu Belokopytov, K Belous, AC Benvenuti, M Berggren, D Bertrand, F Bianchi, M Bigi, MS Bilenky, P Billoir, D Bloch, M Blume, S Blyth, V Bocci, T Bolognese, M Bonesini, W Bonivento, PSL Booth, G Borisov, C Bosio, S Bosworth, O Botner, B Bouquet, C Bourdarios, TJV Bowcock, M Bozzo, P Branchini, KD Brand, T Brenke, RA Brenner, C Bricman, L Brillault, RCA Brown, P Bruckman, J-M Brunet, L Bugge, T Buran, T Burgsmueller, P Buschmann, A Buys, M Caccia, M Calvi, AJ Camacho Rozas, T Camporesi, V Canale, M Canepa, K Cankocak, F Cao, F Carena, P Carrilho, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, L Cerrito, V Chabaud, Ph Charpentier, L Chaussard, J Chauveau, P Checchia, GA Chelkov, R Chierici, P Chliapnikov, P Chochula, V Chorowicz, V Cindro, P Collins, JL Contreras, R Contri, E Cortina, G Cosme, F Cossutti, HB Crawley, D Crennell, G Crosetti, J Cuevas Maestro, S Czellar, E Dahl-Jensen, J Dahm, B Dalmagne, M Dam, G Damgaard, PD Dauncey, M Davenport, W Da Silva, C Defoix, A Deghorain, G Della Ricca, P Delpierre, N Demaria, A De Angelis, H De Boeck, W De Boer, S De Brabandere, C De Clercq, C De La Vaissiere, B De Lotto, A De Min, L De Paula, C De Saint-Jean, H Dijkstra, L Di Ciaccio, F Djama, J Dolbeau, M Donszelmann, K Doroba, M Dracos, J Drees, K-A Drees, M Dris, Y Dufour, F Dupont, D Edsall, R Ehret, G Eigen, T Ekelof, G Ekspong, M Elsing, J-P Engel, N Ershaidat, B Erzen, M Espirito Santo, E Falk, D Fassouliotis, M Feindt, A Ferrer, TA Filippas, A Firestone, P-A Fischer, H Foeth, E Fokitis, F Fontanelli, F Formenti, B Franek, P Frenkiel, DC Fries, AG Frodesen, R Fruhwirth, F Fulda-Quenzer, J Fuster, A Galloni, D Gamba, M Gandelman, C Garcia, J Garcia, C Gaspar, U Gasparini, Ph Gavillet, EN Gazis, D Gele, J-P Gerber, M Gibbs, R Gokieli, B Golob, G Gopal, L Gorn, M Gorski, Yu Gouz, V Gracco, E Graziani, G Grosdidier, K Grzelak, S Gumenyuk, P Gunnarsson, M Gunther, J Guy, F Hahn, S Hahn, Z Hajduk, A Hallgren, K Hamacher, W Hao, FJ Harris, V Hedberg, R Henriques, JJ Hernandez, P Herquet, H Herr, TL Hessing, E Higon, HJ Hilke, TS Hill, S-O Holmgren, PJ Holt, D Holthuizen, S Hoorelbeke, M Houlden, J Hrubec, K Huet, K Hultqvist, JN Jackson, R Jacobsson, P Jalocha, R Janik, G Jarlskog, P Jarry, B Jean-Marie, EK Johansson, L Jonsson, P Jonsson, C Joram, P Juillot, M Kaiser, F Kapusta, K Karafasoulis, M Karlsson, E Karvelas, S Katsanevas, EC Katsoufis, R Keranen, BA Khomenko, NN Khovanski, B King, NJ Kjaer, H Klein, A Klovning, P Kluit, B Koene, P Kokkinias, M Koratzinos, V Kostioukhine, C Kourkoumelis, O Kouznetsov, P-H Kramer, M Krammer, C Kreuter, J Krolikowski, I Kronkvist, Z Krumstein, W Krupinski, P Kubinec, W Kucewicz, K Kurvinen, C Lacasta, I Laktineh, S Lamblot, JW Lamsa, L Lanceri, DW Lane, P Langefeld, V Lapin, I Last, J-P Laugier, R Lauhakangas, G Leder, F Ledroit, V Lefebure, CK Legan, R Leitner, Y Lemoigne, J Lemonne, G Lenzen, V Lepeltier, T Lesiak, D Liko, R Lindner, A Lipniacka, I Lippi, B Loerstad, M Lokajicek, JG Loken, JM Lopez, A Lopez-Fernandez, MA Lopez Aguera, D Loukas, P Lutz, L Lyons, J MacNaughton, G Maehlum, A Maio, V Malychev, C Maocun, J Marco, B Marechal, M Margoni, J-C Marin, C Mariotti, A Markou, T Maron, C Martinez-Rivero, F Martinez-Vidal, S Marti i Garcia, F Matorras, C Matteuzzi, G Matthiae, M Mazzucato, M Mc Cubbin, R Mc Kay, R Mc Nulty, J Medbo, C Meroni, S Meyer, WT Meyer, A Miagkov, M Michelotto, E Migliore, L Mirabito, WA Mitaroff, U Mjoernmark, T Moa, R Moeller, K Moenig, MR Monge, P Morettini, H Mueller, LM Mundim, WJ Murray, B Muryn, G Myatt, F Naraghi, FL Navarria, S Navas, P Negri, S Nemecek, W Neumann, N Neumeister, R Nicolaidou, BS Nielsen, M Nieuwenhuizen, V Nikolaenko, P Niss, A Nomerotski, A Normand, W Oberschulte-Beckmann, V Obraztsov, AG Olshevski, A Onofre, R Orava, K Osterberg, A Ouraou, P Paganini, M Paganoni, P Pages, H Palka, Th D Papadopoulou, K Papageorgiou, L Pape, C Parkes, F Parodi, A Passeri, M Pegoraro, L Peralta, H Pernegger, M Pernicka, A Perrotta, C Petridou, A Petrolini, M Petrovyck, HT Phillips, G Piana, F Pierre, M Pimenta, M Pindo, S Plaszczynski, O Podobrin, ME Pol, G Polok, P Poropat, V Pozdniakov, M Prest, P Privitera, N Pukhaeva, D Radojicic, S Ragazzi, H Rahmani, J Rames, PN Ratoff, AL Read, M Reale, P Rebecchi, NG Redaelli, M Regler, D Reid, PB Renton, LK Resvanis, F Richard, J Richardson, J Ridky, G Rinaudo, I Ripp, A Romero, I Roncagliolo, P Ronchese, L Roos, EI Rosenberg, E Rosso, P Roudeau, T Rovelli, W Ruckstuhl, V Ruhlmann-Kleider, A Ruiz, H Saarikko, Y Sacquin, A Sadovsky, G Sajot, J Salt, J Sanchez, M Sannino, M Schimmelpfennig, H Schneider, U Schwickerath, MAE Schyns, G Sciolla, F Scuri, P Seager, Y Sedykh, AM Segar, A Seitz, R Sekulin, RC Shellard, I Siccama, P Siegrist, S Simonetti, F Simonetto, AN Sisakian, B Sitar, TB Skaali, G Smadja, N Smirnov, O Smirnova, GR Smith, R Sosnowski, D Souza-Santos, T Spassov, E Spiriti, P Sponholz, S Squarcia, C Stanescu, S Stapnes, I Stavitski, F Stichelbaut, A Stocchi, J Strauss, R Strub, B Stugu, M Szczekowski, M Szeptycka, T Tabarelli, JP Tavernet, O Tchikilev, A Tilquin, J Timmermans, LG Tkatchev, T Todorov, DZ Toet, A Tomaradze, B Tome, L Tortora, G Transtromer, D Treille, W Trischuk, G Tristram, A Trombini, C Troncon, A Tsirou, M-L Turluer, IA Tyapkin, M Tyndel, S Tzamarias, B Ueberschaer, O Ullaland, V Uvarov, G Valenti, E Vallazza, C Vander Velde, GW Van Apeldoom, P Van Dam, WK Van Doninck, J Van Eldik, N Vassilopoulos, G Vegni, L Ventura, W Venus, F Verbeure, M Verlato, LS Vertogradov, D Vilanova, P Vincent, L Vitale, E Vlasov, AS Vodopyanov, V Vrba, H Wahlen, C Walck, M Weierstall, P Weilhammer, C Weiser, AM Wetherell, D Wicke, JH Wickens, M Wielers, GR Wilkinson, WSC Williams, M Winter, M Witek, K Woschnagg, K Yip, O Yushchenko, F Zach, C Zacharatou, A Zaitsev, A Zalewska, P Zalewski, D Zavrtanik, E Zevgolatakos, NI Zimin, M Zito, D Zontar, R Zuberi, GC Zucchelli, G Zumerle
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Measurement of αsfrom jet rates in deep inelastic scattering at HERA

Physics Letters B 363:3 (1995) 201-216

Authors:

M Derrick, D Krakauer, S Magill, D Mikunas, B Musgrave, J Repond, R Stanek, RL Talaga, H Zhang, R Ayad, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, P Bruni, G Cara Romeo, G Castellini, M Chiarini, L Cifarelli, F Cindolo, A Contin, M Corradi, I Gialas, P Giusti, G Iacobucci, G Laurenti, G Levi, A Margotti, T Massam, R Nania, C Nemoz, F Palmonari, A Polini, G Sartorelli, R Timellini, Y Zamora Garcia, A Zichichi, A Bargende, A Bornheim, J Crittenden, K Desch, B Diekmann, T Doeker, M Eckert, L Feld, A Frey, M Geerts, M Grothe, H Hartmann, K Heinloth, E Hilger, HP Jakob, UF Katz, S Mengel, J Mollen, E Paul, M Pfeiffer, C Rembser, D Schramm, J Stamm, R Wedemeyer, S Campbell-Robson, A Cassidy, WN Cottingham, N Dyce, B Foster, S George, ME Hayes, GP Heath, HF Heath, CJS Morgado, JA O'Mara, D Piccioni, DG Roff, RJ Tapper, R Yoshida, RR Rau, M Arneodo, M Capua, A Garfagnini, L Iannotti, M Schioppa, G Susinno, A Bernstein, A Caldwell, N Cartiglia, JA Parsons, S Ritz, F Sciulli, PB Straub, L Wai, S Yang, Q Zhu, P Borzemski, J Chwastowski, A Eskreys, K Piotrzkowski, M Zachara

Abstract:

Jet production in deep inelastic scattering for 120 < Q2< 3600 GeV2has been studied using data from an integrated luminosity of 3.2 pb-1collected with the ZEUS detector at HERA. Jets are identified with the JADE algorithm. A cut on the angular distribution of parton emission in the γ*-parton centre-of-mass system minimises the experimental and theoretical uncertainties in the determination of the jet rates. The jet rates, when compared to O(αs2) perturbative QCD calculations, allow a precise determination of αs(Q) in three Q2-intervals. The values are consistent with a running of ifαs(Q), as expected from QCD. Extrapolating to Q = MZ0αs(MZ0) = 0.117 ± 0.005 (stat)-0.005+0.004(systexp) ± 0.007 (systtheory). © 1995.
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