Measurement of the W-->taunu production cross section in pp collisions at square root s=1.8 TeV.

Physical review letters 84:25 (2000) 5710-5715

Authors:

B Abbott, M Abolins, V Abramov, BS Acharya, DL Adams, M Adams, S Ahn, V Akimov, GA Alves, N Amos, EW Anderson, MM Baarmand, VV Babintsev, L Babukhadia, A Baden, B Baldin, S Banerjee, J Bantly, E Barberis, P Baringer, JF Bartlett, U Bassler, A Belyaev, SB Beri, G Bernardi, I Bertram, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, G Blazey, S Blessing, A Boehnlein, NI Bojko, F Borcherding, A Brandt, R Breedon, G Briskin, R Brock, G Brooijmans, A Bross, D Buchholz, V Buescher, VS Burtovoi, JM Butler, W Carvalho, D Casey, Z Casilum, H Castilla-Valdez, D Chakraborty, KM Chan, SV Chekulaev, W Chen, DK Cho, S Choi, S Chopra, BC Choudhary, JH Christenson, M Chung, D Claes, AR Clark, WG Cobau, J Cochran, L Coney, B Connolly, WE Cooper, D Coppage, D Cullen-Vidal, MA Cummings, D Cutts, OI Dahl, K Davis, K De, K Del Signore, M Demarteau, D Denisov, SP Denisov, HT Diehl, M Diesburg, G Di Loreto, P Draper, Y Ducros, LV Dudko, SR Dugad, A Dyshkant, D Edmunds, J Ellison, VD Elvira, R Engelmann, S Eno, G Eppley, P Ermolov, OV Eroshin, J Estrada, H Evans, VN Evdokimov, T Fahland, S Feher, D Fein, T Ferbel, HE Fisk, Y Fisyak, E Flattum, F Fleuret, M Fortner, KC Frame, S Fuess, E Gallas, AN Galyaev, P Gartung, V Gavrilov, RJ Genik, K Genser, CE Gerber, Y Gershtein, B Gibbard, R Gilmartin, G Ginther, B Gobbi, B Gómez, G Gómez, PI Goncharov, JL González Solís, H Gordon, LT Goss, K Gounder, A Goussiou, N Graf, PD Grannis, DR Green, JA Green, H Greenlee, S Grinstein, P Grudberg, S Grünendahl, G Guglielmo, A Gupta, SN Gurzhiev, G Gutierrez, P Gutierrez, NJ Hadley, H Haggerty, S Hagopian, V Hagopian, KS Hahn, RE Hall, P Hanlet, S Hansen, JM Hauptman, C Hays, C Hebert, D Hedin, AP Heinson, U Heintz, T Heuring, R Hirosky, JD Hobbs, B Hoeneisen, JS Hoftun, F Hsieh, AS Ito, SA Jerger, R Jesik, T Joffe-Minor, K Johns, M Johnson, A Jonckheere, M Jones, H Jöstlein, SY Jun, S Kahn, E Kajfasz, D Karmanov, D Karmgard, R Kehoe, SK Kim, B Klima, C Klopfenstein, B Knuteson, W Ko, JM Kohli, D Koltick, AV Kostritskiy, J Kotcher, AV Kotwal, AV Kozelov, EA Kozlovsky, J Krane, MR Krishnaswamy, S Krzywdzinski, M Kubantsev, S Kuleshov, Y Kulik, S Kunori, G Landsberg, A Leflat, F Lehner, H Li, J Li, QZ Li, JG Lima, D Lincoln, SL Linn, J Linnemann, R Lipton, JG Lu, A Lucotte, L Leuking, C Lundstedt, AK Maciel, RJ Madaras, V Manankov, S Mani, HS Mao, R Markeloff, T Marshall, MI Martin, RD Martin, KM Mauritz, B May, AA Mayorov, R McCarthy, J McDonald, T McKibben, T McMahon, HL Melanson, M Merkin, KW Merritt, C Miao, H Miettinen, A Mincer, CS Mishra, N Mokhov, NK Mondal, HE Montgomery, M Mostafa, H da Motta, E Nagy, F Nang, M Narain, VS Narasimham, HA Neal, JP Negret, S Negroni, D Norman, L Oesch, V Oguri, B Olivier, N Oshima, D Owen, P Padley, A Para, N Parashar, R Partridge, N Parua, M Paterno, A Patwa, B Pawlik, J Perkins, M Peters, R Piegaia, H Piekarz, Y Pischalnikov, BG Pope, E Popkov, HB Prosper, S Protopopescu, J Qian, PZ Quintas, R Raja, S Rajagopalan, NW Reay, S Reucroft, M Rijssenbeek, T Rockwell, M Roco, P Rubinov, R Ruchti, J Rutherfoord, A Santoro, L Sawyer, RD Schamberger, H Schellman, A Schwartzman, J Sculli, N Sen, E Shabalina, HC Shankar, RK Shivpuri, D Shpakov, M Shupe, RA Sidwell, H Singh, JB Singh, V Sirotenko, P Slattery, E Smith, RP Smith, R Snihur, GR Snow, J Snow, S Snyder, J Solomon, XF Song, V Sorín, M Sosebee, N Sotnikova, M Souza, NR Stanton, G Steinbrück, RW Stephens, ML Stevenson, F Stichelbaut, D Stoker, V Stolin, DA Stoyanova, M Strauss, K Streets, M Strovink, L Stutte, A Sznajder, J Tarazi, M Tartaglia, TL Thomas, J Thompson, D Toback, TG Trippe, AS Turcot, PM Tuts, P van Gemmeren, V Vaniev, N Varelas, AA Volkov, AP Vorobiev, HD Wahl, J Warchol, G Watts, M Wayne, H Weerts, A White, JT White, JA Wightman, S Willis, SJ Wimpenny, JV Wirjawan, J Womersley, DR Wood, R Yamada, P Yamin, T Yasuda, K Yip, S Youssef, J Yu, Y Yu, M Zanabria, H Zheng, Z Zhou, ZH Zhu, M Zielinski, D Zieminska, A Zieminski, V Zutshi, EG Zverev, A Zylberstejn

Abstract:

We report on a measurement of sigma(pp-->W+X)B(W-->taunu) in pp collisions at sqrt[s]=1.8 TeV at the Fermilab Tevatron. The measurement is based on an integrated luminosity (lum) of 18 pb-1 of data collected with the D0 detector during 1994-1995. We find that sigma(pp-->W+X)B(W-->taunu)=2.22+/-0.09 (stat)+/-0. 10 (syst)+/-0.10 (lum) nb. Lepton universality predicts that the ratio of the tau and electron electroweak charged current couplings to the W boson, gWtau/gWe, be unity. We find gWtau/gWe=0.980+/-0.031, in agreement with lepton universality.

New results on silicon microstrip detectors of CMS tracker

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment Elsevier 447:1-2 (2000) 142-150

Authors:

N Demaria, S Albergo, M Angarano, P Azzi, E Babucci, N Bacchetta, A Bader, G Bagliesi, A Basti, U Biggeri, GM Bilei, D Bisello, D Boemi, G Bolla, F Bosi, L Borrello, D Bortoletto, C Bozzi, S Braibant, H Breuker, M Bruzzi, A Buffini, S Busoni, A Candelori, A Caner, R Castaldi, A Castro, E Catacchini, B Checcucci, P Ciampolini, C Civinini, D Creanza, R D'Alessandro, M Da Rold, M de Palma, R Dell'Orso, R Della Marina, S Dutta, C Eklund, A Elliott-Peisert, G Favro, L Feld, L Fiore, E Focardi, M French, K Freudenreich, A Fürtjes, A Giassi, M Giorgi, A Giraldo, B Glessing, WH Gu, G Hall, R Hammerstrom, T Hebbeker, J Hrubec, M Huhtinen, A Kaminsky, V Karimaki, Koenig, M Krammer, P Lariccia, M Lenzi, M Loreti, K Luebelsmeyer, W Lustermann, P Mättig, G Maggi, M Mannelli, G Mantovani, A Marchioro, C Mariotti, G Martignon, B Mc Evoy, M Meschini, A Messineo, E Migliore, S My, A Paccagnella, F Palla, D Pandoulas, A Papi, G Parrini, D Passeri, M Pieri, S Piperov, R Potenza, V Radicci, F Raffaelli, M Raymond, A Santocchia, B Schmitt, G Selvaggi, L Servoli, G Sguazzoni, R Siedling, L Silvestris, K Skog, A Starodumov, I Stavitski, G Stefanini, P Tempesta, G Tonelli, A Tricomi, T Tuuva, C Vannini, PG Verdini, G Viertel, Z Xie, Li Yahong, S Watts, B Wittmer

Probing Balitsky-Fadin-Kuraev-Lipatov dynamics in the dijet cross section at large rapidity intervals in pp collisions at sqrt[s]=1800 and 630 GeV.

Physical review letters 84:25 (2000) 5722-5727

Authors:

B Abbott, M Abolins, V Abramov, BS Acharya, DL Adams, M Adams, V Akimov, GA Alves, N Amos, EW Anderson, MM Baarmand, VV Babintsev, L Babukhadia, A Baden, B Baldin, S Banerjee, J Bantly, E Barberis, P Baringer, JF Bartlett, U Bassler, A Bean, A Belyaev, SB Beri, G Bernardi, I Bertram, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, G Blazey, S Blessing, A Boehnlein, NI Bojko, F Borcherding, A Brandt, R Breedon, G Briskin, R Brock, G Brooijmans, A Bross, D Buchholz, V Buescher, VS Burtovoi, JM Butler, W Carvalho, D Casey, Z Casilum, H Castilla-Valdez, D Chakraborty, KM Chan, SV Chekulaev, W Chen, DK Cho, S Choi, S Chopra, BC Choudhary, JH Christenson, M Chung, D Claes, AR Clark, WG Cobau, J Cochran, L Coney, B Connolly, WE Cooper, D Coppage, D Cullen-Vidal, MA Cummings, D Cutts, OI Dahl, K Davis, K De, K Del Signore, M Demarteau, D Denisov, SP Denisov, HT Diehl, M Diesburg, G Di Loreto, P Draper, Y Ducros, LV Dudko, SR Dugad, A Dyshkant, D Edmunds, J Ellison, VD Elvira, R Engelmann, S Eno, G Eppley, P Ermolov, OV Eroshin, J Estrada, H Evans, VN Evdokimov, T Fahland, S Feher, D Fein, T Ferbel, HE Fisk, Y Fisyak, E Flattum, F Fleuret, M Fortner, KC Frame, S Fuess, E Gallas, AN Galyaev, P Gartung, V Gavrilov, RJ Genik, K Genser, CE Gerber, Y Gershtein, B Gibbard, R Gilmartin, G Ginther, B Gobbi, B Gómez, G Gómez, PI Goncharov, JL González Solís, H Gordon, LT Goss, K Gounder, A Goussiou, N Graf, PD Grannis, JA Green, H Greenlee, S Grinstein, P Grudberg, S Grünendahl, G Guglielmo, A Gupta, SN Gurzhiev, G Gutierrez, P Gutierrez, NJ Hadley, H Haggerty, S Hagopian, V Hagopian, KS Hahn, RE Hall, P Hanlet, S Hansen, JM Hauptman, C Hays, C Hebert, D Hedin, AP Heinson, U Heintz, T Heuring, R Hirosky, JD Hobbs, B Hoeneisen, JS Hoftun, AS Ito, SA Jerger, R Jesik, T Joffe-Minor, K Johns, M Johnson, A Jonckheere, M Jones, H Jöstlein, SY Jun, A Juste, S Kahn, E Kajfasz, D Karmanov, D Karmgard, R Kehoe, SK Kim, B Klima, C Klopfenstein, B Knuteson, W Ko, JM Kohli, AV Kostritskiy, J Kotcher, AV Kotwal, AV Kozelov, EA Kozlovsky, J Krane, MR Krishnaswamy, S Krzywdzinski, M Kubantsev, S Kuleshov, Y Kulik, S Kunori, G Landsberg, A Leflat, F Lehner, J Li, QZ Li, JG Lima, D Lincoln, SL Linn, J Linnemann, R Lipton, JG Lu, A Lucotte, L Lueking, C Lundstedt, AK Maciel, RJ Madaras, V Manankov, S Mani, HS Mao, R Markeloff, T Marshall, MI Martin, RD Martin, KM Mauritz, B May, AA Mayorov, R McCarthy, J McDonald, T McKibben, T McMahon, HL Melanson, M Merkin, KW Merritt, C Miao, H Miettinen, D Mihalcea, A Mincer, CS Mishra, N Mokhov, NK Mondal, HE Montgoemry, M Mostafa, H da Motta, E Nagy, F Nang, M Narain, VS Narasimham, HA Neal, JP Negret, S Negroni, D Norman, L Oesch, V Oguri, B Olivier, N Oshima, P Padley, LJ Pan, A Para, N Parashar, R Partridge, N Parua, M Paterno, A Patwa, B Pawlik, J Perkins, M Peters, R Piegaia, H Piekarz, BG Pope, E Popkov, HB Prosper, S Protopopescu, J Qian, PZ Quintas, R Raja, S Rajagopalan, NW Reay, S Reucroft, M Rijssenbeek, T Rockwell, M Roco, P Rubinov, R Ruchti, J Rutherfoord, A Santoro, L Sawyer, RD Schamberger, H Schellman, A Schwartzman, J Sculli, N Sen, E Shabalina, HC Shankar, RK Shivpuri, D Shpakov, M Shupe, RA Sidwell, H Singh, JB Singh, V Sirotenko, P Slattery, E Smith, RP Smith, R Snihur, GR Snow, J Snow, S Snyder, J Solomon, XF Song, V Sorín, M Sosebee, N Sotnikova, M Souza, NR Stanton, G Steinbrück, RW Stephens, ML Stevenson, F Stichelbaut, D Stoker, V Stolin, DA Stoyanova, M Strauss, K Streets, M Strovink, L Stutte, A Sznajder, J Tarazi, W Taylor, S Tentindo-Repond, TL Thomas, J Thompson, D Toback, TG Trippe, AS Turcot, PM Tuts, P van Gemmeren, V Vaniev, N Varelas, AA Volkov, AP Vorobiev, HD Wahl, H Wang, J Warchol, G Watts, M Wayne, H Weerts, A White, JT White, D Whiteson, JA Wightman, S Willis, SJ Wimpenny, JV Wirjawan, J Womersley, DR Wood, R Yamada, P Yamin, T Yasuda, K Yip, S Youssef, J Yu, Z Yu, M Zanabria, H Zheng, Z Zhou, ZH Zhu, M Zielinski, D Zieminska, A Zieminski, V Zutshi, EG Zverev, A Zylberstejn

Abstract:

Inclusive dijet production at large pseudorapidity intervals (Deltaeta) between the two jets has been suggested as a regime for observing Balitsky-Fadin-Kuraev-Lipatov (BFKL) dynamics. We have measured the dijet cross section for large Deltaeta in pp collisions at sqrt[s]=1800 and 630 GeV using the D0 detector. The partonic cross section increases strongly with the size of Deltaeta. The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of alphaBFKL(20 GeV)=1.65+/-0.07.

Diffractive Dijets with a Leading Antiproton in p¯p Collisions at s=1800 GeV

Physical Review Letters American Physical Society (APS) 84:22 (2000) 5043-5048

Authors:

T Affolder, H Akimoto, A Akopian, MG Albrow, P Amaral, SR Amendolia, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, T Asakawa, W Ashmanskas, M Atac, F Azfar, P Azzi-Bacchetta, N Bacchetta, MW Bailey, S Bailey, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, M Barone, G Bauer, F Bedeschi, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, B Bevensee, A Bhatti, M Binkley, D Bisello, RE Blair, C Blocker, K Bloom, B Blumenfeld, SR Blusk, A Bocci, A Bodek, W Bokhari, G Bolla, Y Bonushkin, K Borras, D Bortoletto, J Boudreau, A Brandl, S van den Brink, C Bromberg, M Brozovic, N Bruner, E Buckley-Geer, J Budagov, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, M Campbell, W Carithers, J Carlson, D Carlsmith, J Cassada, A Castro, D Cauz, A Cerri, AW Chan, PS Chang, PT Chang, J Chapman, C Chen, YC Chen, M-T Cheng, M Chertok, G Chiarelli, I Chirikov-Zorin, G Chlachidze, F Chlebana, L Christofek, ML Chu, S Cihangir, CI Ciobanu, AG Clark, A Connolly, M Convery, J Conway, J Cooper, M Cordelli, J Cranshaw, D Cronin-Hennessy, R Cropp, R Culbertson, D Dagenhart, F DeJongh, S Dell'Agnello, M Dell'Orso, R Demina, L Demortier, M Deninno, PF Derwent, T Devlin, JR Dittmann, S Donati, J Done, T Dorigo, N Eddy, K Einsweiler, JE Elias, E Engels, W Erdmann, D Errede, S Errede, Q Fan, RG Feild, C Ferretti, RD Field, I Fiori, B Flaugher, GW Foster, M Franklin, J Freeman, J Friedman, Y Fukui, S Galeotti, M Gallinaro, T Gao, M Garcia-Sciveres, AF Garfinkel, P Gatti, C Gay, S Geer, DW Gerdes, P Giannetti, V Glagolev, M Gold, J Goldstein, A Gordon, AT Goshaw, Y Gotra, K Goulianos, C Green, L Groer, C Grosso-Pilcher, M Guenther, G Guillian, J Guimaraes da Costa, RS Guo, C Haber, E Hafen, SR Hahn, C Hall, T Handa, R Handler, W Hao, F Happacher, K Hara, AD Hardman, RM Harris, F Hartmann, K Hatakeyama, J Hauser, J Heinrich, A Heiss, M Herndon, B Hinrichsen, KD Hoffman, C Holck, R Hollebeek, L Holloway, R Hughes, J Huston, J Huth, H Ikeda, J Incandela, G Introzzi, J Iwai, Y Iwata, E James, H Jensen, M Jones, U Joshi, H Kambara, T Kamon, T Kaneko, K Karr, H Kasha, Y Kato, TA Keaffaber, K Kelley, M Kelly, RD Kennedy, R Kephart, D Khazins, T Kikuchi, M Kirk, BJ Kim, HS Kim, MJ Kim, SH Kim, YK Kim, L Kirsch, S Klimenko, P Koehn, A Köngeter, K Kondo, J Konigsberg, K Kordas, A Korn, A Korytov, E Kovacs, J Kroll, M Kruse, SE Kuhlmann, K Kurino, T Kuwabara, AT Laasanen, N Lai, S Lami, S Lammel, JI Lamoureux, M Lancaster, G Latino, T LeCompte, AM Lee, S Leone, JD Lewis, M Lindgren, TM Liss, JB Liu, YC Liu, N Lockyer, J Loken, M Loreti, D Lucchesi, P Lukens, S Lusin, L Lyons, J Lys, R Madrak, K Maeshima, P Maksimovic, L Malferrari, M Mangano, M Mariotti, G Martignon, A Martin, JAJ Matthews, J Mayer, P Mazzanti, KS McFarland, P McIntyre, E McKigney, P Melese, M Menguzzato, A Menzione, C Mesropian, T Miao, R Miller, JS Miller, H Minato, S Miscetti, M Mishina, G Mitselmakher, N Moggi, C Moore, E Moore, R Moore, Y Morita, A Mukherjee, T Muller, A Munar, P Murat, S Murgia, M Musy, J Nachtman, S Nahn, H Nakada, T Nakaya, I Nakano, C Nelson, D Neuberger, C Newman-Holmes, C-YP Ngan, P Nicolaidi, H Niu, L Nodulman, A Nomerotski, SH Oh, T Ohmoto, T Ohsugi, R Oishi, T Okusawa, J Olsen, C Pagliarone, F Palmonari, R Paoletti, V Papadimitriou, SP Pappas, D Partos, J Patrick, G Pauletta, M Paulini, C Paus, L Pescara, TJ Phillips, G Piacentino, KT Pitts, R Plunkett, A Pompos, L Pondrom, G Pope, M Popovic, F Prokoshin, J Proudfoot, F Ptohos, G Punzi, K Ragan, A Rakitine, D Reher, A Reichold, W Riegler, A Ribon, F Rimondi, L Ristori, WJ Robertson, A Robinson, T Rodrigo, S Rolli, L Rosenson, R Roser, R Rossin, WK Sakumoto, D Saltzberg, A Sansoni, L Santi, H Sato, P Savard, P Schlabach, EE Schmidt, MP Schmidt, M Schmitt, L Scodellaro, A Scott, A Scribano, S Segler, S Seidel, Y Seiya, A Semenov, F Semeria, T Shah, MD Shapiro, PF Shepard, T Shibayama, M Shimojima, M Shochet, J Siegrist, G Signorelli, A Sill, P Sinervo, P Singh, AJ Slaughter, K Sliwa, C Smith, FD Snider, A Solodsky, J Spalding, T Speer, P Sphicas, F Spinella, M Spiropulu, L Spiegel, J Steele, A Stefanini, J Strologas, F Strumia, D Stuart, K Sumorok, T Suzuki, T Takano, R Takashima, K Takikawa, P Tamburello, M Tanaka, B Tannenbaum, W Taylor, M Tecchio, PK Teng, K Terashi, S Tether, D Theriot, R Thurman-Keup, P Tipton, S Tkaczyk, K Tollefson, A Tollestrup, H Toyoda, W Trischuk, JF de Troconiz, J Tseng, N Turini, F Ukegawa, T Vaiciulis, J Valls, S Vejcik, G Velev, R Vidal, R Vilar, I Volobouev, D Vucinic, RG Wagner, RL Wagner, J Wahl, NB Wallace, AM Walsh, C Wang, CH Wang, MJ Wang, T Watanabe, D Waters, T Watts, R Webb, H Wenzel, WC Wester, AB Wicklund, E Wicklund, HH Williams, P Wilson, BL Winer, D Winn, S Wolbers, D Wolinski, J Wolinski, S Wolinski, S Worm, X Wu, J Wyss, A Yagil, W Yao, GP Yeh, P Yeh, J Yoh, C Yosef, T Yoshida, I Yu, S Yu, A Zanetti, F Zetti, S Zucchelli

Measurement of azimuthal asymmetries in deep inelastic scattering

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 481:2-4 (2000) 199-212

Authors:

J Breitweg, S Chekanov, M Derrick, D Krakauer, S Magill, B Musgrave, A Pellegrino, J Repond, R Stanek, R Yoshida, MCK Mattingly, G Abbiendi, F Anselmo, P Antonioli, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, G Cara Romeo, G Castellini, L Cifarelli, F Cindolo, A Contin, N Coppola, M Corradi, S de Pasquale, P Giusti, G Iacobucci, G Laurenti, G Levi, A Margotti, T Massam, R Nania, F Palmonari, A Pesci, A Polini, G Sartorelli, Y Zamora Garcia, A Zichichi, C Amelung, A Bornheim, I Brock, K Coböken, J Crittenden, R Deffner, H Hartmann, K Heinloth, E Hilger, P Irrgang, HP Jakob, A Kappes, UF Katz, R Kerger, E Paul, H Schnurbusch, A Stifutkin, J Tandler, KC Voss, A Weber, H Wieber, DS Bailey, O Barret, NH Brook, B Foster, GP Heath, HF Heath, JD McFall, D Piccioni, E Rodrigues, J Scott, RJ Tapper, M Capua, A Mastroberardino, M Schioppa, G Susinno, HY Jeoung, JY Kim, JH Lee, IT Lim, KJ Ma, MY Pac, A Caldwell, W Liu, X Liu, B Mellado, S Paganis, S Sampson, WB Schmidke, F Sciulli, J Chwastowski, A Eskreys, J Figiel, K Klimek, K Olkiewicz, K Piotrzkowski, MB Przybycień, P Stopa, L Zawiejski

Abstract:

The distribution of the azimuthal angle for the charged hadrons has been studied in the hadronic centre-of-mass system for neutral current deep inelastic positron-proton scattering with the ZEUS detector at HERA. Measurements of the dependence of the moments of this distribution on the transverse momenta of the charged hadrons are presented. Asymmetries that can be unambiguously attributed to perturbative QCD processes have been observed for the first time. (C) 2000 Elsevier Science B.V.