Study of the effective transverse momentum of partons in the proton using prompt photons in photoproduction at HERA

Chekanov, S Derrick, M Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, GC Cifarelli, L Cindolo, F Contin, A Corradi, M De Pasquale, S Giusti, P Iacobucci, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Sartorelli, G Zichichi, A Aghuzumtsyan, G Brock, I Goers, S Hartmann, H Hilger, E Irrgang, P Jakob, HP Kappes, A Katz, UF Kerger, R Kind, O Paul, E Rautenberg, J Schnurbusch, H Stifutkin, A Tandler, J Voss, KC Weber, A Wieber, H Bailey, DS Brook, NH Cole, JE Foster, B Heath, GP Heath, HF Robins, S Rodrigues, E Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Helbich, M Liu, W Liu, X Mellado, B Paganis, S Sampson, S Schmidke, WB Sciulli, F Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Przybycien, MB Stopa, P Zawiejski, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Szuba, D Kotanski, A Bauerdick, LAT Behrens, U Borras, K Chiochia, V Crittenden, J Dannheim, D Desler, K Drews, G Fox-Murphy, A Fricke, U Geiser, A Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hebbel, K Hillert, S Koch, W Kotz, U Kowalski, H Labes, H Lohr, B Mankel, R Martens, J Martinez, M Milite, M Moritz, M Notz, D Petrucci, MC Polini, A Savin, AA Schneekloth, U Selonke, F Stonjek, S Wolf, G Wollmer, U Whitmore, JJ Wichmann, R Youngman, C Zeuner, W Coldewey, C Viani, ALD Meyer, A Schlenstedt, S Barbagli, G Gallo, E Parenti, A Pelfer, PG Bamberger, A Benen, A Coppola, N Markun, P Raach, H Wolfle, S Bell, M Bussey, PJ Doyle, AT Glasman, C Lee, SW Lupi, A McCance, GJ Saxon, DH Skillicorn, IO Bodmann, B Gendner, N Holm, U Salehi, H Wick, K Yildirim, A Ziegler, A Carli, T Garfagnini, A Gialas, I Lohrmann, E Foudas, C Goncalo, R Long, KR Metlica, F Miller, DB Tapper, AD Walker, R Cloth, P Filges, D Ishii, T Kuze, M Nagano, K Tokushuku, K Yamada, S Yamazaki, Y Barakbaev, AN Boos, EG Pokrovskiy, NS Zhautykov, BO Ahn, SH Lee, SB Park, SK Lim, H Son, D Barreiro, F Garcia, G Gonzalez, O Labarga, L del Peso, J Redondo, I Terron, J Vazquez, M Barbi, M Corriveau, F Padhi, S Stairs, DG Wing, M Tsurugai, T Antonov, A Bashkirov, V Danilov, P Dolgoshein, BA Gladkov, D Sosnovtsev, V Suchkov, S Dementiev, RK Ermolov, PF Golubkov, YA Katkov, II Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Levchenko, BB Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Vlasov, NN Zotkin, SA Bokel, C Botje, M Engelen, J Grijpink, S Koffeman, E Kooijman, P Schagen, S van Sighem, A Tassi, E Tiecke, H Tuning, N Velthuis, JJ Vossebeld, J Wiggers, L de Wolf, E Brummer, N Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Boogert, S Cooper-Sarkar, AM Devenish, RCE Ferrando, J Grosse-Knetter, J Matsushita, T Rigby, M Ruske, O Sutton, MR Walczak, R Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dusini, S Limentani, S Longhin, A Posocco, M Stanco, L Turcato, M Adamczyk, L Iannotti, L Oh, BY Saull, PRB Toothacker, WS Iga, Y D'Agostini, G Marini, G Nigro, A Cormack, C Hart, JC McCubbin, NA Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Williams, DC Park, IH Pavel, N Abramowicz, H Dagan, S Gabareen, A Kananov, S Kreisel, A Levy, A Abe, T Fusayasu, T Kohno, T Umemori, K Yamashita, T Hamatsu, R Hirose, T Inuzuka, M Kitamura, S Matsuzawa, K Nishimura, T Arneodo, M Cartiglia, N Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Ruspa, M Sacchi, R Solano, A Staiano, A Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Mirea, A Sabetfakhri, A Butterworth, JM Gwenlan, C Hayes, ME Heaphy, EA Jones, TW Lane, JB West, BJ Ciborowski, J Ciesielski, R Grzelak, G Nowak, RJ Pawlak, JM Plucinski, P Smalska, B Sztuk, J Tymieniecka, T Ukleja, J Zakrzewski, JA Zarnecki, AF Adamus, M Deppe, O Eisenberg, Y Gladilin, LK Hochman, D Karshon, U Breitweg, J Chapin, D Cross, R Kcira, D Lammers, S Reeder, DD Smith, WH Deshpande, A Dhawan, S Hughes, VW Straub, PB Bhadra, S Catterall, CD Frisken, WR Hall-Wilton, R Khakzad, M Menary, S

S. Chekanov et al., Study of the effective transverse momentum of partons in the proton using prompt photons in photoproduction at HERA, PHYS LETT B, 511(1), 2001, pp. 19-32

42

INGLESE

Article

Physics

PHYSICS LETTERS B

0370-2693 → ACNP

511

1

2001

19 - 32

ISI

0370-2693(20010628)511:1<19:SOTETM>2.0.ZU;2-O

The photoproduction of prompt photons, together with an accompanying jet, h as been measured with the ZEUS detector at HERA using an integrated luminos ity of 38.6 pb(-1). A study of the effective transverse momentum. (k(T)), o f partons in the proton, as modelled within the framework of the PYTHIA Mon te Carlo. gives a value of (k(T)) = 1.69 +/- 0.18(-0.20)(+0.18) GeV for the gammap centre-of-mass energy range 134 < W < 251 GeV. This result is in ag reement with the previously observed trend in hadron-hadron scattering for (k(T)) to rise with interaction energy. (C) 2001 Elsevier Science B.V. All rights reserved.