251. Dijet angular distributions in photoproduction of charm at HERA
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Chekanov, S, Derrick, M, Krakauer, D, Loizides, J H, Magill, S, Musgrave, B, Repond, J, Yoshida, R, Mattingly, M C K, Antonioli, P, Bari, G, Basile, M, Bellagamba, L, Boscherini, D, Bruni, A, Bruni, G, Romeo, G C, Cifarelli, L, Cindolo, F, Contin, A, Corradi, M, De Pasquale, S, Giusti, P, Iacobucci, G, Margotti, A, Nania, R, Palmonari, F, Pesci, A, Sartorelli, G, Zichichi, A, Aghuzumtsyan, G, Bartsch, D, Brock, I, Goers, S, Hartmann, H, Hilger, E, Irrgang, P, Jakob, H P, Kappes, A, Katz, U F, Kind, O, Meyer, U, Paul, E, Rautenberg, J, Renner, R, Stifutkin, A, Tandler, J, Voss, K C, Wang, M, Weber, A, Bailey, D S, Brook, N H, Cole, J E, Foster, B, Heath, G P, Heath, H F, Robins, S, Rodrigues, E, Scott, J, Tapper, R J, Wing, M, Capua, M, Mastroberardino, A, Schioppa, M, Susinno, G, Kim, J Y, Kim, Y K, Lee, J H, Lim, I T, Pac, M Y, Caldwell, A, Helbich, M, Liu, X, Mellado, B, Ning, Y, Paganis, S, Ren, Z, Schmidke, W, Sciulli, F, Chwastowski, J, Eskreys, A, Figiel, J, Olkiewicz, K, Stopa, P, Zawiejski, L, Adamczyk, L, Bold, T, Grabowska-Bold, I, Kisielewska, D, Kowal, A M, Kowal, M, Kowalski, T, Przybycien, M, Suszycki, L, Szuba, D, Szuba, J, Kotanski, A, Slominski, W, Bauerdick, L A T, Behrens, U, Boch, I, Borras, K, Chiochia, V, Dannheim, D, Drews, G, Fourletova, J, Fricke, U, Geiser, A, Goebel, F, Gottlicher, P, Gutsche, O, Haas, T, Hain, W, Hartner, G F, Hillert, S, Kahle, B, Kotz, U, Kowalski, H, Kramberger, G, Labes, H, Lelas, D, Lohr, B, Mankel, R, Melzer-Pellmann, I A, Moritz, M, Nguyen, C N, Notz, D, Petrucci, M C, Polini, A, Raval, A, Schneekloth, U, Selonke, F, Wessoleck, H, Wolf, G, Youngman, C, Zeuner, W, Schlenstedt, S, Barbagli, G, Gallo, E, Genta, C, Pelfer, P G, Bamberger, A, Benen, A, Coppola, N, Bell, M, Bussey, P J, Doyle, A T, Glasman, C, Hamilton, J, Hanlon, S, Lee, S W, Lupi, A, Saxon, D, Skillicorn, O I, Gialas, I, Bodmann, B, Carli, T, Holm, U, Klimek, K, Krumnack, N, Lohrmann, E, Milite, M, Salehi, H, Stonjek, S, Wick, K, Ziegler, A, Collins-Tooth, C, Foudas, C, Goncalo, R, Long, K R, Tapper, A D, Cloth, P, Filges, D, Kuze, M, Nagano, K, Tokushuku, K, Yamada, S, Yamazaki, Y, Barakbaev, A, Boos, E G, Pokrovskiy, N S, Zhautykov, B O, Lim, H, Son, D, Piotrzkowski, K, Barreiro, F, Gonzalez, O, Labarga, L, Del Peso, J, Tassi, E, Terron, J, Vazquez, M, Barbi, M, Corriveau, F, Gliga, S, Lainesse, J, Padhi, S, Stairs, D G, Tsurugai, T, Antonov, A, Danilov, P, Dolgoshein, B A, Gladkov, D, Sosnovtsev, V, Suchkov, S, Dementiev, R K, Ermolov, R, Golubkov, Y A, Katkov, I I, Khein, L A, Korzhavina, I A, Kuzmin, V A, Levchenko, B B, Lukina, O Y, Proskuryakov, A S, Shcheglova, L M, Vlasov, N N, Zotkin, S A, Grijpink, S, Koffeman, E, Kooijman, K, Maddox, E, Pellegrino, A, Schagen, S, Tiecke, H, Tuning, N, Velthuis, J J, Wiggers, L, De Wolf, E, Brummer, N, Bylsma, B, Durkin, L S, Ling, T Y, Boogert, S, Cooper-Sarkar, A M, Devenish, R C E, Ferrando, J, Grzelak, G, Patel, S, Rigby, M, Sutton, M R, Walczak, R, Bertolin, A, Brugnera, R, Carlin, R, Dal Corso, F, Dusini, S, Garfagnini, A, Limentani, S, Longhin, A, Parenti, A, Posocco, P, Stanco, L, Turcato, M, Heaphy, E A, Metlica, F, Oh, B Y, Saull, P R B, Whitmore, J J, Iga, Y, D'Agostini, G D, Marini, G, Nigro, A, Cormack, C, Hart, J C, McCubbin, N A, Heusch, C, Park, I H, Pavel, N, Abramowicz, H, Gabareen, A, Kananov, S, Kreisel, A, Levy, A, Abe, T, Fusayasu, T, Kagawa, S, Kohno, T, Tawara, T, Yamashita, T, Hamatsu, R, Hirose, T, Inuzuka, M, Kitamura, S, Matsuzawa, K, Nishimura, T, Arneodo, M, Ferrero, M I, Monaco, V, Ruspa, M, Sacchi, R, Solano, A, Koop, T, Levman, G M, Martin, J F, Mirea, A, Butterworth, J M, Gwenlan, C, Hall-Wilton, R, Jones, T W, Lightwood, M S, West, B J, Ciborowski, J, Ciesielski, R, Nowak, R J, Pawlak, J M, Sztuk, J, Tymieniecka, T, Ukleja, A, Ukleja, J, Zarnecki, A F, Adamus, M, Plucinski, P, Eisenberg, Y, Gladilin, L K, Hochman, D, Karshon, U, Kcira, D, Lammers, S, Li, L, Reeder, D D, Savin, A A, Smith, W H, Deshpande, A, Dhawan, S, Hughes, V W, Straub, P B, Bhadra, S, Catterall, C D, Fourletov, S, Menary, S, Soares, M, Standage, J, ZEUS Collaborat, Chekanov, S, Derrick, M, Krakauer, D, Loizides, J H, Magill, S, Musgrave, B, Repond, J, Yoshida, R, Mattingly, M C K, Antonioli, P, Bari, G, Basile, M, Bellagamba, L, Boscherini, D, Bruni, A, Bruni, G, Romeo, G C, Cifarelli, L, Cindolo, F, Contin, A, Corradi, M, De Pasquale, S, Giusti, P, Iacobucci, G, Margotti, A, Nania, R, Palmonari, F, Pesci, A, Sartorelli, G, Zichichi, A, Aghuzumtsyan, G, Bartsch, D, Brock, I, Goers, S, Hartmann, H, Hilger, E, Irrgang, P, Jakob, H P, Kappes, A, Katz, U F, Kind, O, Meyer, U, Paul, E, Rautenberg, J, Renner, R, Stifutkin, A, Tandler, J, Voss, K C, Wang, M, Weber, A, Bailey, D S, Brook, N H, Cole, J E, Foster, B, Heath, G P, Heath, H F, Robins, S, Rodrigues, E, Scott, J, Tapper, R J, Wing, M, Capua, M, Mastroberardino, A, Schioppa, M, Susinno, G, Kim, J Y, Kim, Y K, Lee, J H, Lim, I T, Pac, M Y, Caldwell, A, Helbich, M, Liu, X, Mellado, B, Ning, Y, Paganis, S, Ren, Z, Schmidke, W, Sciulli, F, Chwastowski, J, Eskreys, A, Figiel, J, Olkiewicz, K, Stopa, P, Zawiejski, L, Adamczyk, L, Bold, T, Grabowska-Bold, I, Kisielewska, D, Kowal, A M, Kowal, M, Kowalski, T, Przybycien, M, Suszycki, L, Szuba, D, Szuba, J, Kotanski, A, Slominski, W, Bauerdick, L A T, Behrens, U, Boch, I, Borras, K, Chiochia, V, Dannheim, D, Drews, G, Fourletova, J, Fricke, U, Geiser, A, Goebel, F, Gottlicher, P, Gutsche, O, Haas, T, Hain, W, Hartner, G F, Hillert, S, Kahle, B, Kotz, U, Kowalski, H, Kramberger, G, Labes, H, Lelas, D, Lohr, B, Mankel, R, Melzer-Pellmann, I A, Moritz, M, Nguyen, C N, Notz, D, Petrucci, M C, Polini, A, Raval, A, Schneekloth, U, Selonke, F, Wessoleck, H, Wolf, G, Youngman, C, Zeuner, W, Schlenstedt, S, Barbagli, G, Gallo, E, Genta, C, Pelfer, P G, Bamberger, A, Benen, A, Coppola, N, Bell, M, Bussey, P J, Doyle, A T, Glasman, C, Hamilton, J, Hanlon, S, Lee, S W, Lupi, A, Saxon, D, Skillicorn, O I, Gialas, I, Bodmann, B, Carli, T, Holm, U, Klimek, K, Krumnack, N, Lohrmann, E, Milite, M, Salehi, H, Stonjek, S, Wick, K, Ziegler, A, Collins-Tooth, C, Foudas, C, Goncalo, R, Long, K R, Tapper, A D, Cloth, P, Filges, D, Kuze, M, Nagano, K, Tokushuku, K, Yamada, S, Yamazaki, Y, Barakbaev, A, Boos, E G, Pokrovskiy, N S, Zhautykov, B O, Lim, H, Son, D, Piotrzkowski, K, Barreiro, F, Gonzalez, O, Labarga, L, Del Peso, J, Tassi, E, Terron, J, Vazquez, M, Barbi, M, Corriveau, F, Gliga, S, Lainesse, J, Padhi, S, Stairs, D G, Tsurugai, T, Antonov, A, Danilov, P, Dolgoshein, B A, Gladkov, D, Sosnovtsev, V, Suchkov, S, Dementiev, R K, Ermolov, R, Golubkov, Y A, Katkov, I I, Khein, L A, Korzhavina, I A, Kuzmin, V A, Levchenko, B B, Lukina, O Y, Proskuryakov, A S, Shcheglova, L M, Vlasov, N N, Zotkin, S A, Grijpink, S, Koffeman, E, Kooijman, K, Maddox, E, Pellegrino, A, Schagen, S, Tiecke, H, Tuning, N, Velthuis, J J, Wiggers, L, De Wolf, E, Brummer, N, Bylsma, B, Durkin, L S, Ling, T Y, Boogert, S, Cooper-Sarkar, A M, Devenish, R C E, Ferrando, J, Grzelak, G, Patel, S, Rigby, M, Sutton, M R, Walczak, R, Bertolin, A, Brugnera, R, Carlin, R, Dal Corso, F, Dusini, S, Garfagnini, A, Limentani, S, Longhin, A, Parenti, A, Posocco, P, Stanco, L, Turcato, M, Heaphy, E A, Metlica, F, Oh, B Y, Saull, P R B, Whitmore, J J, Iga, Y, D'Agostini, G D, Marini, G, Nigro, A, Cormack, C, Hart, J C, McCubbin, N A, Heusch, C, Park, I H, Pavel, N, Abramowicz, H, Gabareen, A, Kananov, S, Kreisel, A, Levy, A, Abe, T, Fusayasu, T, Kagawa, S, Kohno, T, Tawara, T, Yamashita, T, Hamatsu, R, Hirose, T, Inuzuka, M, Kitamura, S, Matsuzawa, K, Nishimura, T, Arneodo, M, Ferrero, M I, Monaco, V, Ruspa, M, Sacchi, R, Solano, A, Koop, T, Levman, G M, Martin, J F, Mirea, A, Butterworth, J M, Gwenlan, C, Hall-Wilton, R, Jones, T W, Lightwood, M S, West, B J, Ciborowski, J, Ciesielski, R, Nowak, R J, Pawlak, J M, Sztuk, J, Tymieniecka, T, Ukleja, A, Ukleja, J, Zarnecki, A F, Adamus, M, Plucinski, P, Eisenberg, Y, Gladilin, L K, Hochman, D, Karshon, U, Kcira, D, Lammers, S, Li, L, Reeder, D D, Savin, A A, Smith, W H, Deshpande, A, Dhawan, S, Hughes, V W, Straub, P B, Bhadra, S, Catterall, C D, Fourletov, S, Menary, S, Soares, M, Standage, J, and ZEUS Collaborat
- Abstract
Dijet angular distributions of photoproduction events in which a D*(+/- ) meson is produced in association with one of two energetic jets have been measured with the ZEUS detector at HERA, using an integrated luminosity of 120 pb( -1). Differential cross sections as a function of the angle between the charm-jet and the proton-beam direction in the dijet rest frame have been measured for samples enriched in direct or resolved photon events. The results are compared with predictions from leading order parton-shower Monte Carlo models and with next-to-leading-order QCD calculations. The angular distributions show clear evidence for the existence of charm originating from the photon. (C) 2003 Published by Elsevier B.V.