Subjet distributions in deep inelastic scattering at HERA

European Physical Journal C 63:4 (2009) 527-548

Authors:

S Chekanov, M Derrick, S Magill, B Musgrave, D Nicholass, J Repond, R Yoshida, MCK Mattingly, P Antonioli, G Bari, L Bellagamba, D Boscherini, A Bruni, G Bruni, F Cindolo, M Corradi, G Iacobucci, A Margotti, R Nania, A Polini, S Antonelli, M Basile, M Bindi, L Cifarelli, A Contin, S De Pasquale, G Sartorelli, A Zichichi, D Bartsch, I Brock, H Hartmann, E Hilger, HP Jakob, M Jüngst, AE Nuncio-Quiroz, E Paul, U Samson, V Schönberg, R Shehzadi, M Wlasenko, NH Brook, GP Heath, JD Morris, M Kaur, P Kaur, I Singh, M Capua, S Fazio, A Mastroberardino, M Schioppa, G Susinno, E Tassi, JY Kim, ZA Ibrahim, F Mohamad Idris, B Kamaluddin, WAT Wan Abdullah, Y Ning, Z Ren, F Sciulli, J Chwastowski, A Eskreys, J Figiel, A Galas, K Olkiewicz, B Pawlik, P Stopa, L Zawiejski, L Adamczyk, T Bołd, I Grabowska-Bołd, D Kisielewska, J Łukasik, M Przybycień, L Suszycki, A Kotański, W Słomiński, O Behnke, U Behrens, C Blohm, A Bonato, K Borras, D Bot, R Ciesielski, N Coppola, S Fang, J Fourletova, A Geiser, P Göttlicher, J Grebenyuk, I Gregor, T Haas, W Hain, A Hüttmann, F Januschek, B Kahle, II Katkov, U Klein, U Kötz, H Kowalski

Abstract:

Subjet distributions were measured in neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 81.7 pb-1. Jets were identified using the k T cluster algorithm in the laboratory frame. Subjets were defined as jet-like substructures identified by a reapplication of the cluster algorithm at a smaller value of the resolution parameter ycut. Measurements of subjet distributions for jets with exactly two subjets for ycut=0.05 are presented as functions of observables sensitive to the pattern of parton radiation and to the colour coherence between the initial and final states. Perturbative QCD predictions give an adequate description of the data. © 2009 Springer-Verlag / Società Italiana di Fisica.

Measurement of D (+/-) and D (0) production in deep inelastic scattering using a lifetime tag at HERA

EUR PHYS J C 63:3 (2009) 171-188

Authors:

S Chekanov, M Derrick, S Magill, B Musgrave, D Nicholass, J Repond, R Yoshida, MCK Mattingly, P Antonioli, G Bari, L Bellagamba, D Boscherini, A Bruni, G Bruni, F Cindolo, M Corradi, G Iacobucci, A Margotti, R Nania, A Polini, S Antonelli, M Basile, M Bindi, L Cifarelli, A Contin, S De Pasquale, G Sartorelli, A Zichichi, D Bartsch, I Brock, H Hartmann, E Hilger, HP Jakob, M Jungst, AE Nuncio-Quiroz, E Paul, U Samson, V Schonberg, R Shehzadi, M Wlasenko, NH Brook, GP Heath, JD Morris, M Kaur, P Kaur, I Singh, M Capua, S Fazio, A Mastroberardino, M Schioppa, G Susinno, E Tassi, JY Kim, ZA Ibrahim, F Idris, B Kamaluddin, WATW Abdullah, Y Ning, Z Ren, F Sciulli, J Chwastowski, A Eskreys, J Figiel, A Galas, K Olkiewicz, B Pawlik, P Stopa, L Zawiejski, L Adamczyk, T Bold, I Grabowska-Bold, D Kisielewska, J Laukasik, M Przybycien, L Suszycki, A Kotanski, W Sominski, O Behnke, U Behrens, C Blohm, A Bonato, K Borras, D Bot, R Ciesielski, N Coppola, S Fang, J Fourletova, A Geiser, P Gottlicher, J Grebenyuk, I Gregor, T Haas, W Hain, A Huttmann, F Januschek, B Kahle, II Katkov, U Klein, U Kotz, H Kowalski, M Lisovyi, E Lobodzinska, B Lohr, R Mankel, IA Melzer-Pellmann, S Miglioranzi, A Montanari, T Namsoo, D Notz, A Parenti, L Rinaldi, P Roloff, I Rubinsky, U Schneekloth, A Spiridonov, D Szuba, J Szuba, T Theedt, J Ukleja, G Wolf, K Wrona, AGY Molina, C Youngman, W Zeuner, V Drugakov, W Lohmann, S Schlenstedt, G Barbagli, E Gallo, PG Pelfer, A Bamberger, D Dobur, F Karstens, NN Vlasov, PJ Bussey, AT Doyle, W Dunne, M Forrest, M Rosin, DH Saxon, IO Skillicorn, I Gialas, K Papageorgiu, U Holm, R Klanner, E Lohrmann, H Perrey, P Schleper, T Schorner-Sadenius, J Sztuk, H Stadie, M Turcato, C Foudas, C Fry, KR Long, AD Tapper, T Matsumoto, K Nagano, K Tokushuku, S Yamada, Y Yamazaki, AN Barakbaev, EG Boos, NS Pokrovskiy, BO Zhautykov, V Aushev, O Bachynska, M Borodin, I Kadenko, A Kozulia, V Libov, D Lontkovskyi, I Makarenko, I Sorokin, A Verbytskyi, O Volynets, D Son, J de Favereau, K Piotrzkowski, F Barreiro, C Glasman, M Jimenez, L Labarga, J del Peso, E Ron, M Soares, J Terron, C Uribe-Estrada, M Zambrana, F Corriveau, C Liu, J Schwartz, R Walsh, C Zhou, T Tsurugai, A Antonov, BA Dolgoshein, D Gladkov, V Sosnovtsev, A Stifutkin, S Suchkov, RK Dementiev, PF Ermolov, LK Gladilin, YA Golubkov, LA Khein, IA Korzhavina, VA Kuzmin, BB Levchenko, OY Lukina, AS Proskuryakov, LM Shcheglova, DS Zotkin, I Abt, A Caldwell, D Kollar, B Reisert, WB Schmidke, G Grigorescu, A Keramidas, E Koffeman, P Kooijman, A Pellegrino, H Tiecke, M Vazquez, L Wiggers, N Brummer, B Bylsma, LS Durkin, A Lee, TY Ling, PD Allfrey, MA Bell, AM Cooper-Sarkar, RCE Devenish, J Ferrando, B Foster, C Gwenlan, K Horton, K Oliver, A Robertson, R Walczak, A Bertolin, F Dal Corso, S Dusini, A Longhin, L Stanco, P Bellan, R Brugnera, R Carlin, A Garfagnini, S Limentani, BY Oh, A Raval, JJ Whitmore, Y Iga, G D'Agostini, G Marini, A Nigro, JE Cole, JC Hart, H Abramowicz, R Ingbir, S Kananov, A Levy, A Stern, M Kuze, J Maeda, R Hori, S Kagawa, N Okazaki, S Shimizu, T Tawara, R Hamatsu, H Kaji, S Kitamura, O Ota, YD Ri, M Costa, MI Ferrero, V Monaco, R Sacchi, V Sola, A Solano, M Arneodo, M Ruspa, S Fourletov, JF Martin, TP Stewart, SK Boutle, JM Butterworth, R Hall-Wilton, TW Jones, JH Loizides, MR Sutton, M Wing, B Brzozowska, J Ciborowski, G Grzelak, P Kulinski, P Luzniak, J Malka, RJ Nowak, JM Pawlak, W Perlanski, T Tymieniecka, AF Zarnecki, M Adamus, P Plucinski, A Ukleja, Y Eisenberg, D Hochman, U Karshon, E Brownson, DD Reeder, AA Savin, WH Smith, H Wolfe, S Bhadra, CD Catterall, Y Cui, G Hartner, S Menary, U Noor, J Standage, J Whyte, ZEUS Collaboration

Abstract:

The production of D-+/-- and D-0-mesons has been measured with the ZEUS detector at HERA using an integrated luminosity of 133.6 pb(-1). The measurements cover the kinematic range 5 < Q(2) < 1000 GeV2, 0.02 < y < 0.7, 1.5 < p(T)(D) < 15 GeV and |eta(D)| < 1.6. Combinatorial background to the D-meson signals is reduced by using the ZEUS microvertex detector to reconstruct displaced secondary vertices. Production cross sections are compared with the predictions of next-to-leading-order QCD, which is found to describe the data well. Measurements are extrapolated to the full kinematic phase space in order to obtain the open-charm contribution, F-2(c (c) over bar), to the proton structure function, F-2.

Exclusive photoproduction of ϒmesons at HERA

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 680:1 (2009) 4-12

Authors:

S Chekanov, M Derrick, S Magill, B Musgrave, D Nicholass, J Repond, R Yoshida, MCK Mattingly, P Antonioli, G Bari, L Bellagamba, D Boscherini, G Bruni, F Cindolo, M Corradi, G Iacobucci, A Margotti, R Nania, A Polini, S Antonelli, M Basile, M Bindi, L Cifarelli, A Contin, S De Pasquale, G Sartorelli, A Zichichi, D Bartsch, I Brock, H Hartmann, E Hilger, HP Jakob, M Jüngst, AE Nuncio-Quiroz, E Paul, U Samson, V Schönberg, R Shehzadi, M Wlasenko, NH Brook, GP Heath, JD Morris, M Kaur, P Kaur, I Singh, M Capua, S Fazio, A Mastroberardino, M Schioppa, G Susinno, E Tassi, JY Kim, ZA Ibrahim, FM Idris, B Kamaluddin, WAT Wan Abdullah, Y Ning, Z Ren, F Sciulli, J Chwastowski, A Eskreys, J Figiel, A Galas, K Olkiewicz, B Pawlik, P Stopa, L Zawiejski, L Adamczyk, T Bołd, I Grabowska-Bołd, D Kisielewska, J Łukasik, M Przybycień, L Suszycki, A Kotański, W Słomiński, O Behnke, J Behr, U Behrens, C Blohm, K Borras, D Bot, R Ciesielski, N Coppola, S Fang, A Geiser, P Göttlicher, J Grebenyuk, I Gregor, T Haas, W Hain, A Hüttmann, F Januschek, B Kahle, II Katkov, U Klein, U Kötz, H Kowalski, M Lisovyi, E Lobodzinska

Abstract:

The exclusive photoproduction reaction γ p → Υ{hooked} p has been studied with the ZEUS experiment in ep collisions at HERA using an integrated luminosity of 468 pb-1. The measurement covers the kinematic range 60 < W < 220 GeV and Q2 < 1   GeV2, where W is the photon-proton centre-of-mass energy and Q2 is the photon virtuality. These results, which represent the analysis of the full ZEUS data sample for this channel, are compared to predictions based on perturbative QCD. © 2009 Elsevier B.V.

Multi-lepton production at high transverse momentum at HERA

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 680:1 (2009) 13-23

Authors:

S Chekanov, M Derrick, S Magill, B Musgrave, D Nicholass, J Repond, R Yoshida, MCK Mattingly, P Antonioli, G Bari, L Bellagamba, D Boscherini, A Bruni, G Bruni, F Cindolo, M Corradi, G Iacobucci, A Margotti, R Nania, A Polini, S Antonelli, M Basile, M Bindi, L Cifarelli, A Contin, S De Pasquale, G Sartorelli, A Zichichi, D Bartsch, I Brock, H Hartmann, E Hilger, HP Jakob, M Jüngst, AE Nuncio-Quiroz, E Paul, U Samson, V Schönberg, R Shehzadi, M Wlasenko, JD Morris, M Kaur, P Kaur, I Singh, M Capua, S Fazio, A Mastroberardino, M Schioppa, G Susinno, E Tassi, JY Kim, ZA Ibrahim, FM Idris, B Kamaluddin, WATW Abdullah, Y Ning, Z Ren, F Sciulli, J Chwastowski, A Eskreys, J Figiel, A Galas, K Olkiewicz, B Pawlik, P Stopa, L Zawiejski, L Adamczyk, T Bołd, I Grabowska-Bołd, D Kisielewska, J Łukasik, M Przybycień, L Suszycki, A Kotański, W Słomiński, O Behnke, J Behr, U Behrens, C Blohm, K Borras, D Bot, R Ciesielski, N Coppola, S Fang, A Geiser, P Göttlicher, J Grebenyuk, I Gregor, T Haas, W Hain, A Hüttmann, F Januschek, B Kahle, II Katkov, U Klein, U Kötz, H Kowalski, M Lisovyi, E Lobodzinska, B Löhr

Abstract:

A search for events containing two or more high-transverse-momentum isolated leptons has been performed in ep collisions with the ZEUS detector at HERA using the full collected data sample, corresponding to an integrated luminosity of 480 pb -1. The number of observed events has been compared with the prediction from the Standard Model, searching for possible deviations, especially for multi-lepton events with invariant mass larger than 100 GeV. Good agreement with the Standard Model has been observed. Total and differential cross sections for di-lepton production have been measured in a restricted phase space dominated by photon-photon collisions. © 2009 Elsevier B.V.

Measurement of D ± and D 0 production in deep inelastic scattering using a lifetime tag at HERA

European Physical Journal C 63:2 (2009) 171-188

Authors:

S Chekanov, M Derrick, S Magill, B Musgrave, D Nicholass, J Repond, R Yoshida, MCK Mattingly, P Antonioli, G Bari, L Bellagamba, D Boscherini, A Bruni, G Bruni, F Cindolo, M Corradi, G Iacobucci, A Margotti, R Nania, A Polini, S Antonelli, M Basile, M Bindi, L Cifarelli, A Contin, S De Pasquale, G Sartorelli, A Zichichi, D Bartsch, I Brock, H Hartmann, E Hilger, HP Jakob, M Jüngst, AE Nuncio-Quiroz, E Paul, U Samson, V Schönberg, R Shehzadi, M Wlasenko, NH Brook, GP Heath, JD Morris, M Kaur, P Kaur, I Singh, M Capua, S Fazio, A Mastroberardino, M Schioppa, G Susinno, E Tassi, JY Kim, ZA Ibrahim, F Mohamad Idris, B Kamaluddin, WAT Wan Abdullah, Y Ning, Z Ren, F Sciulli, J Chwastowski, A Eskreys, J Figiel, A Galas, K Olkiewicz, B Pawlik, P Stopa, L Zawiejski, L Adamczyk, T Bołd, I Grabowska-Bołd, D Kisielewska, J Łukasik, M Przybycień, L Suszycki, A Kotański, W Słomiński, O Behnke, U Behrens, C Blohm, A Bonato, K Borras, D Bot, R Ciesielski, N Coppola, S Fang, J Fourletova, A Geiser, P Göttlicher, J Grebenyuk, I Gregor, T Haas, W Hain, A Hüttmann, F Januschek, B Kahle, II Katkov, U Klein, U Kötz, H Kowalski

Abstract:

The production of D ±- and D 0-mesons has been measured with the ZEUS detector at HERA using an integrated luminosity of 133.6 pb-1. The measurements cover the kinematic range 5