Measurement of dijet cross-sections in low Q(2) ep collisions and the extraction of an effective parton density for the virtual photon

Authors
Adloff, C Andreev, V Andrieu, B Arkadov, V Astvatsatourov, A Ayyaz, I Babaev, A Bahr, J Baranov, P Barrelet, E Bartel, T Bassler, U Bate, P Beglarian, A Behnke, O Behrend, HJ Beier, C Belousov, A Berger, C Bernardi, G Berndt, T Bertrand-Coremans, G Biddulph, P Bizot, JC Boudry, V Braunschweig, W Brisson, V Brown, DP Bruckner, W Bruel, P Bruncko, D Burger, J Busser, FW Buniatian, A Burke, S Burrage, A Buschhorn, G Calvet, D Campbell, AJ Carli, T Chabert, E Charlet, M Chyla, J Clarke, D Clerbaux, B Contreras, JG Cormack, C Coughlan, JA Cousinou, MC Cox, BE Cozzika, G Cvach, J Dainton, JB Dau, WD Daum, K David, M Davidsson, M De Roeck, A De Wolf, EA Delcourt, B Demirchyan, R Diaconu, C Dirkmann, M Dixon, P Dlugosz, W Donovan, KT Dowell, JD Droutskoi, A Ebert, J Eckerlin, G Eckstein, D Efremenko, V Egli, S Eichler, R Eisele, F Eisenhandler, E Elsen, E Enzenberger, M Erdmann, M Fahr, AB Faulkner, PJW Favart, L Fedotov, A Felst, R Feltesse, J Ferencei, J Ferrarotto, F Fleischer, M Flugge, G Fomenko, A Formanek, J Foster, JM Franke, G Gabathuler, E Gabathuler, K Gaede, F Garvey, J Gassner, J Gayler, J Gerhards, R Ghazaryan, S Glazov, A Goerlich, L Gogitidze, N Goldberg, M Gorelov, I Grab, C Grassler, H Greenshaw, T Griffiths, RK Grindhammer, G Hadig, T Haidt, D Hajduk, L Hampel, M Haustein, V Haynes, WJ Heinemann, B Heinzelmann, G Henderson, RCW Hengstmann, S Henschel, H Heremans, R Herynek, I Hewitt, K Hiller, KH Hilton, CD Hladky, J Hoffmann, D Horisberger, R Hurling, S Ibbotson, M Issever, C Jacquet, M Jaffre, M Janauschek, L Jansen, DM Jonsson, L Johnson, DP Jones, M Jung, H Kastli, HK Kander, M Kant, D Kapichine, M Karlsson, M Karschnik, O Katzy, J Kaufmann, O Kausch, M Keller, N Kenyon, IR Kermiche, S Keuker, C Kiesling, C Klein, M Kleinwort, C Knies, G Kohne, JH Kolanoski, H Kolya, SD Korbel, V Kostka, P Kotelnikov, SK Kramerkamper, T Krasny, MW Krehbiel, H Krucker, D Kruger, K Kupper, A Kuster, H Kuhlen, M Kurca, T Lachnit, W Lahmann, R Lamb, D Landon, MPJ Lange, W Langenegger, U Lebedev, A Lehner, F Lemaitre, V Lemrani, R Lendermann, V Levonian, S Lindstroem, M Lobo, G Lobodzinska, E Lubimov, V Luders, S Luke, D Lytkin, L Magnussen, N Mahlke-Kruger, H Malden, N Malinovski, E Malinovski, I Maracek, R Marage, P Marks, J Marshall, R Martyn, HU Martyniak, J Maxfield, SJ McMahon, TR Mehta, A Meier, K Merkel, P Metlica, F Meyer, A Meyer, A Meyer, H Meyer, J Meyer, PO Mikocki, S Milstead, D Mohr, R Mohrdieck, S Mondragon, M Moreau, F Morozov, A Morris, JV Muller, D Muller, K Murin, P Nagovizin, V Naroska, B Naumann, J Naumann, T Negri, I Newman, PR Nguyen, HK Nicholls, TC Niebergall, F Niebuhr, C Niedzballa, C Niggli, H Nix, O Nowak, G Nunnemann, T Oberlack, H Olsson, JE Ozerov, D Palmen, P Panassik, V Pascaud, C Passaggio, S Patel, GD Pawletta, H Perez, E Phillips, JP Pieuchot, A Pitzl, D Poschl, R Pope, G Povh, B Rabbertz, K Rauschenberger, J Reimer, P Reisert, B Reyna, D Rick, H Riess, S Rizvi, E Robmann, P Roosen, R Rosenbauer, K Rostovtsev, A Rouse, F Royon, C Rusakov, S Rybicki, K Sankey, DPC Schacht, P Scheins, J Schilling, FP Schleif, S Schleper, P Schmidt, D Schmidt, D Schoeffel, L Schroder, V Schultz-Coulon, HC Sefkow, F Semenov, A Shekelyan, V Sheviakov, I Shtarkov, LN Siegmon, G Sirois, Y Sloan, T Smirnov, P Smith, M Solochenko, V Soloviev, Y Spaskov, V Specka, A Spitzer, H Squinabol, F Stamen, R Steffen, P Steinberg, R Steinhart, J Stella, B Stellberger, A Stiewe, J Straumann, U Struczinski, W Sutton, JP Swart, M Tapprogge, S Tasevsky, M Tchernyshov, V Tchetchelnitski, S Theissen, J Thompson, G Thompson, PD Tobien, N Todenhagen, R Traynor, D Truol, P Tsipolitis, G Turnau, J Tzamariudaki, E Udluft, S Usik, A Valkar, S Valkarova, A Vallee, C Van Esch, P Van Haecke, A Van Mechelen, P Vazdik, Y Villet, G Wacker, K Wallny, R Walter, T Waugh, B Weber, G Weber, M Wegener, D Wegner, A Wengler, T Werner, M West, LR White, G Wiesand, S Wilksen, T Willard, S Winde, M Winter, GG Wissing, C Wittek, C Wittmann, E Wobisch, M Wollatz, H Wunsch, E Zacek, J Zalesak, J Zhang, Z Zhokin, A Zini, P Zomer, F Zsembery, J zur Nedden, M
Citation
C. Adloff et al., Measurement of dijet cross-sections in low Q(2) ep collisions and the extraction of an effective parton density for the virtual photon, EUR PHY J C, 13(3), 2000, pp. 397-414
Citations number
54
Categorie Soggetti
Physics
Journal title
EUROPEAN PHYSICAL JOURNAL C
ISSN journal
14346044 → ACNP
Volume
13
Issue
3
Year of publication
2000
Pages
397 - 414
Database
ISI
SICI code
1434-6044(200004)13:3<397:MODCIL>2.0.ZU;2-F
Abstract
The triple-differential dijet cross-section, d(3)sigma(ep)/dQ(2)d (E) over bar(t)(2) dx(gamma)(jets), is measured with the H1 detector at HERA as a fu nction of the photon virtuality the fraction of the photon's momentum carri ed by the parton entering the hard scattering, x(gamma)(jets), and the squa re of the mean transverse energy, (E) over bar(t)(2), of the two highest E- t jets. Jets are found using a longitudinal boost-invariant k(T) clustering algorithm in the gamma*p center of mass frame. The measurements cover the ranges 1.6 < Q(2) < 80 GeV2 in virtuality and 0.1 < y < 0.7 in inelasticity y. The results are well described by leading order QCD models which includ e the effects of a resolved component to the virtual photon. Models which t reat the photon as point-like fail to describe the data. An effective leadi ng order parton density for the virtual photon is extracted as a function o f the photon virtuality, the probing scale and the parton momentum fraction . The a:, and probing scale dependences of the parton density show characte ristic features of photon structure, and a suppression of this structure wi th increasing Q(2) is seen.