Prof Roman Walczak: Publications

Measurement of dijet cross sections for events with a leading neutron in photoproduction at HERA

Nuclear Physics B 596:1-2 (2001) 3-29

Authors:

Abstract:

Differential cross sections for dijet photoproduction in association with a leading neutron using the reaction e⁺ + p → e⁺ + n + jet + jet + Xr have been measured with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb^-1. The fraction of dijet events with a leading neutron in the final state was studied as a function of the jet kinematic variables. The cross sections were measured for jet transverse energies E^jet T > 6 GeV, neutron energy En > 400 GeV, and neutron production angle θn < 0.8 mrad. The data are broadly consistent with factorization of the lepton and hadron vertices and with a simple one-pion-exchange model. © 2001 Elsevier Science B.V. All rights reserved.

Measurement of open beauty production in photoproduction at HERA

European Physical Journal C 18:4 (2001) 625-637

Authors:

Abstract:

The production and semi-leptonic decay of heavy quarks have been studied in the photoproduction process e⁺p → e⁺ + dijet + e^- + X with the ZEUS detector at HERA using an integrated luminosity of 38.5 pb^-1. Events with photon-proton centre-of-mass energies, Wγ��, between 134 and 269 GeV and a photon virtuality, Q², less than 1 GeV² were selected requiring at least two jets of transverse energy E^jet1(2) T > 7(6) GeV and an electron in the final state. The electrons were identified by employing the ionisation energy loss measurement. The contribution of beauty quarks was determined using the transverse momentum of the electron relative to the axis of the closest jet, p^rel T. The data, after background subtraction, were fit with a Monte Carlo simulation including beauty and charm decays. The measured beauty cross section was extrapolated to the parton level with the b quark restricted to the region of transverse momentum p^b T > = 5 GeV and pseudorapidity |η^b| < 2. The extrapolated cross section is 1.6 ± 0.4 (stat.)^+0.3 -0.5(syst.)^+0.2 -0.4(ext.) nb. The result is compared to a perturbative QCD calculation performed to next-to-leading order.

Measurement of dijet cross sections for events with a leading neutron in photoproduction at HERA

NUCLEAR PHYSICS B 596:1-2 (2001) 3-29

Authors:

J Breitweg, S Chekanov, M Derrick, D Krakauer, S Magill, B Musgrave, A Pellegrino, J Repond, R Stanek, R Yoshida, MCK Mattingly, P Antonioli, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, GC Romeo, L Cifarelli, F Cindolo, A Contin, M Corradi, S De Pasquale, P Giusti, G Iacobucci, G Levi, A Margotti, T Massam, R Nania, F Palmonari, A Pesci, G Sartorelli, 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, J Rautenberg, H Schnurbusch, A Stifutkin, J Tandler, KC Voss, A Weber, H Wieber, DS Bailey, O Barret, NH Brook, B Foster, GP Heath, HF Heath, 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 Przybycien, P Stopa, L Zawiejski, B Bednarek, K Jelen, D Kisielewska, AM Kowal, T Kowalski, M Przybycien, E Rulikowska-Zarebska, L Suszycki, D Szuba, A Kotanski, LAT Bauerdick, U Behrens, JK Bienlein, K Borras, V Chiochia, D Dannheim, K Desler, G Drews, A Fox-Murphy, U Fricke, F Goebel, S Goers, P Göttlicher, R Graciani, T Haas, W Hain, GF Hartner, K Hebbel, S Hillert, W Koch, U Kötz, H Kowalski, H Labes, B Löhr, R Mankel, J Martens, M Martínez, M Milite, M Moritz, D Notz, MC Petrucci, A Polini, M Rohde, AA Savin, U Schneekloth, F Selonke, M Sievers, S Stonjek, G Wolf, U Wollmer, C Youngman, W Zeuner, C Coldewey, ALD Viani, A Meyer, S Schlenstedt, PB Straub, G Barbagli, E Gallo, A Parenti, PG Pelfer, A Bamberger, A Benen, N Coppola, S Eisenhardt, P Markun, H Raach, S Wölfle, PJ Bussey, M Bell, AT Doyle, C Glasman, SW Lee, A Lupi, N Macdonald, GJ McCance, DH Saxon, LE Sinclair, IO Skillicorn, R Waugh, I Bohnet, N Gendner, U Holm, A Meyer-Larsen, H Salehi, K Wick, T Carli, A Garfagnini, I Gialas, LK Gladilin, D Kçira, R Klanner, E Lohrmann, R Gonçalo, KR Long, DB Miller, AD Tapper, R Walker, P Cloth, D Filges, T Ishii, M Kuze, K Nagano, K Tokushuku, S Yamada, Y Yamazaki, SH Ahn, SB Lee, SK Park, H Lim, D Son, F Barreiro, G García, O González, L Labarga, J del Peso, I Redondo, J Terrón, M Vázquez, M Barbi, F Corriveau, DS Hanna, A Ochs, S Padhi, DG Stairs, M Wing, T Tsurugai, A Antonov, V Bashkirov, M Danilov, BA Dolgoshein, D Gladkov, V Sosnovtsev, S Suchkov, RK Dementiev, PF Ermolov, YA Golubkov, II Katkov, LA Khein, NA Korotkova, IA Korzhavina, VA Kuzmin, OY Lukina, AS Proskuryakov, LM Shcheglova, AN Solomin, NN Vlasov, SA Zotkin, C Bokel, M Botje, N Brümmer, J Engelen, S Grijpink, E Koffeman, P Kooijman, S Schagen, A van Sighem, E Tassi, H Tiecke, N Tuning, JJ Velthuis, J Vossebeld, L Wiggers, E de Wolf, B Bylsma, LS Durkin, J Gilmore, CM Ginsburg, CL Kim, TY Ling, S Boogert, AM Cooper-Sarkar, RCE Devenish, J Grosse-Knetter, T Matsushita, O Ruske, MR Sutton, R Walczak, A Bertolin, R Brugnera, R Carlin, F Dal Corso, S Dusini, S Limentani, A Longhin, M Posocco, L Stanco, M Turcato, L Adamczyk, L Iannotti, BY Oh, JR Okrasinski, PRB Saull, WS Toothacker, JJ Whitmore, Y Iga, G D'Agostini, G Marini, A Nigro, C Cormack, JC Hart, NA McCubbin, TP Shah, D Epperson, C Heusch, HFW Sadrozinski, A Seiden, R Wichmann, DC Williams, IH Park, N Pavel, H Abramowicz, S Dagan, S Kananov, A Kreisel, A Levy, T Abe, T Fusayasu, T Kohno, K Umemori, T Yamashita, R Hamatsu, T Hirose, M Inuzuka, S Kitamura, K Matsuzawa, T Nishimura, M Arneodo, N Cartiglia, R Cirio, M Costa, MI Ferrero, S Maselli, V Monaco, C Peroni, M Ruspa, R Sacchi, A Solano, A Staiano, DC Bailey, CP Fagerstroem, R Galea, T Koop, GM Levman, JF Martin, A Mirea, A Sabetfakhri, JM Butterworth, ME Hayes, EA Heaphy, TW Jones, JB Lane, BJ West, J Ciborowski, R Ciesielski, G Grzelak, RJ Nowak, JM Pawlak, R Pawlak, B Smalska, T Tymieniecka, AK Wróblewski, JA Zakrzewski, AF Zarnecki, M Adamus, T Gadaj, O Deppe, Y Eisenberg, D Hochman, U Karshon, WF Badgett, D Chapin, R Cross, C Foudas, S Mattingly, DD Reeder, WH Smith, A Vaiciulis, T Wildschek, M Wodarczyk, A Deshpande, S Dhawan, VW Hughes, S Bhadra, C Catterall, JE Cole, WR Frisken, R Hall-Wilton, M Khakzad, S Menary

Search for resonance decays to a (ν)over-bar plus jet in e⁺p scattering at DESY HERA - art. no. 052002

PHYSICAL REVIEW D 63:5 (2001) ARTN 052002

Authors:

J Breitweg, S Chekanov, M Derrick, D Krakauer, S Magill, B Musgrave, A Pellegrino, J Repond, R Stanek, R Yoshida, MCK Mattingly, P Antonioli, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, GC Romeo, L Cifarelli, F Cindolo, A Contin, M Corradi, S De Pasquale, P Giusti, G Iacobucci, G Levi, A Margotti, T Massam, R Nania, F Palmonari, A Pesci, G Sartorelli, 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, J Rautenberg, H Schnurbusch, A Stifutkin, J Tandler, KC Voss, A Weber, H Wieber, DS Bailey, O Barret, NH Brook, B Foster, GP Heath, HF Heath, 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 Przybycien, P Stopa, L Zawiejski, B Bednarek, K Jelen, D Kisielewska, AM Kowal, T Kowalski, M Przybycien, E Rulikowska-Zarebska, L Suszycki, D Szuba, A Kotanski, LAT Bauerdick, U Behrens, JK Bienlein, K Borras, V Chiochia, D Dannheim, K Desler, G Drews, A Fox-Murphy, U Fricke, F Goebel, S Goers, P Göttlicher, R Graciani, T Haas, W Hain, GF Hartner, D Hasell, K Hebbel, S Hillert, M Kasemann, W Koch, U Kötz, H Kowalski, H Labes, L Lindemann, B Löhr, R Mankel, J Martens, M Martínez, M Milite, M Moritz, D Notz, MC Petrucci, A Polini, M Rohde, AA Savin, U Schneekloth, F Selonke, M Sievers, S Stonjek, G Wolf, U Wollmer, C Youngman, W Zeuner, C Coldewey, ALD Viani, A Meyer, S Schlenstedt, PB Straub, G Barbagli, E Gallo, A Parenti, PG Pelfer, A Bamberger, A Benen, N Coppola, S Eisenhardt, P Markun, H Raach, S Wölfle, PJ Bussey, M Bell, AT Doyle, C Glasman, SW Lee, A Lupi, N Macdonald, GJ McCance, DH Saxon, LE Sinclair, IO Skillicorn, R Waugh, I Bohnet, N Gendner, U Holm, A Meyer-Larsen, H Salehi, K Wick, T Carli, A Garfagnini, I Gialas, LK Gladilin, D Kçira, R Klanner, E Lohrmann, R Gonçalo, KR Long, DB Miller, AD Tapper, R Walker, U Mallik, P Cloth, D Filges, T Ishii, M Kuze, K Nagano, K Tokushuku, S Yamada, Y Yamazaki, SH Ahn, SB Lee, SK Park, H Lim, IH Park, D Son, F Barreiro, G García, O González, L Labarga, J del Peso, I Redondo, J Terrón, M Vázquez, M Barbi, F Corriveau, DS Hanna, A Ochs, S Padhi, DG Stairs, M Wing, T Tsurugai, A Antonov, V Bashkirov, M Danilov, BA Dolgoshein, D Gladkov, V Sosnovtsev, S Suchkov, RK Dementiev, PF Ermolov, YA Golubkov, II Katkov, LA Khein, NA Korotkova, IA Korzhavina, VA Kuzmin, OY Lukina, AS Proskuryakov, LM Shcheglova, AN Solomin, NN Vlasov, SA Zotkin, C Bokel, M Botje, N Brümmer, J Engelen, S Grijpink, E Koffeman, P Kooijman, S Schagen, A van Sighem, E Tassi, H Tiecke, N Tuning, JJ Velthuis, J Vossebeld, L Wiggers, E de Wolf, B Bylsma, LS Durkin, J Gilmore, CM Ginsburg, CL Kim, TY Ling, S Boogert, AM Cooper-Sarkar, RCE Devenish, J Grosse-Knetter, T Matsushita, O Ruske, MR Sutton, R Walczak, A Bertolin, R Brugnera, R Carlin, F Dal Corso, U Dosselli, S Dusini, S Limentani, M Morandin, M Posocco, L Stanco, R Stroili, M Turcato, C Voci, L Adamczyk, L Iannotti, BY Oh, JR Okrasinski, PRB Saull, WS Toothacker, JJ Whitmore, Y Iga, G D'Agostini, G Marini, A Nigro, C Cormack, JC Hart, NA McCubbin, TP Shah, D Epperson, C Heusch, HFW Sadrozinski, A Seiden, R Wichmann, DC Williams, N Pavel, H Abramowicz, S Dagan, S Kananov, A Kreisel, A Levy, T Abe, T Fusayasu, K Umemori, T Yamashita, R Hamatsu, T Hirose, M Inuzuka, S Kitamura, T Nishimura, M Arneodo, N Cartiglia, R Cirio, M Costa, MI Ferrero, S Maselli, V Monaco, C Peroni, M Ruspa, R Sacchi, A Solano, A Staiano, DC Bailey, CP Fagerstroem, R Galea, T Koop, GM Levman, JF Martin, RS Orr, S Polenz, A Sabetfakhri, D Simmons, JM Butterworth, ME Hayes, EA Heaphy, TW Jones, JB Lane, BJ West, J Ciborowski, R Ciesielski, G Grzelak, RJ Nowak, JM Pawlak, R Pawlak, B Smalska, T Tymieniecka, AK Wróblewski, JA Zakrzewski, AF Zarnecki, M Adamus, T Gadaj, O Deppe, Y Eisenberg, D Hochman, U Karshon, WF Badgett, D Chapin, R Cross, C Foudas, S Mattingly, DD Reeder, WH Smith, A Vaiciulis, T Wildschek, M Wodarczyk, A Deshpande, S Dhawan, VW Hughes, S Bhadra, C Catterall, JE Cole, WR Frisken, R Hall-Wilton, M Khakzad, S Menary

Measurement of exclusive ω electroproduction at HERA

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 487:3-4 (2000) 273-288

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, J Rautenberg, 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, 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 exclusive electroproduction of ω mesons, ep → e ω p, has been studied in the kinematic range 3 < Q2 < 20 GeV2, 40 < W < 120 GeV and |t| < 0.6 GeV2 with the ZEUS detector at HERA using an integrated luminosity of 37.7 pb-1. The ω mesons were identified via the decay ω → π+ π- π0. The exclusive cross section in the above kinematic region is σ(ep) → e ω p = 0.108 ± 0.014 (stat.) ± 0.026(syst.) nb. The reaction ep → e φ p, φ → π+ π- π0, has also been measured. The cross sections, as well as the ratios σ γ·p → ωp/σ γ · p → p0p and σ γ · p → ωp/σγ·p → φp, are presented as a function of W and Q2. Thus, for the first time, the properties of ω electroproduction can be compared to those of p0,φ and J/ψ electroproduction at high W. (C) 2000 Elsevier Science B.V.

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