Professor Brian Foster OBE, FRS: Publications

Multi-leptons with high transverse momentum at HERA

Journal of High Energy Physics 2009:10 (2009)

Authors:

FD Aaron, H Abramowicz, I Abt, L Adamczyk, M Adamus, M Aldaya Martin, C Alexa, K Alimujiang, V Andreev, S Antonelli, P Antonioli, A Antonov, B Antunovic, M Arneodo, A Asmone, V Aushev, O Bachynska, S Backovic, A Baghdasaryan, A Bamberger, AN Barakbaev, G Barbagli, G Bari, F Barreiro, E Barrelet, W Bartel, D Bartsch, M Basile, K Begzsuren, O Behnke, J Behr, U Behrens, L Bellagamba, A Belousov, A Bertolin, S Bhadra, M Bindi, JC Bizot, C Blohm, T Bold, EG Boos, M Borodin, K Borras, D Boscherini, D Bot, V Boudry, SK Boutle, I Bozovic-Jelisavcic, J Bracinik, G Brandt, M Brinkmann, V Brisson, I Brock, E Brownson, R Brugnera, N Brümmer, D Bruncko, A Bruni, G Bruni, B Brzozowska, A Bunyatyan, G Buschhorn, PJ Bussey, JM Butterworth, B Bylsma, L Bystritskaya, A Caldwell, AJ Campbell, KB Cantun Avila, M Capua, R Carlin, F Cassol-Brunner, CD Catterall, K Cerny, V Cerny, S Chekanov, V Chekelian, A Cholewa, J Chwastowski, J Ciborowski, R Ciesielski, L Cifarelli, F Cindolo, A Contin, JG Contreras, AM Cooper-Sarkar, N Coppola, M Corradi, F Corriveau, M Costa, JA Coughlan, G Cozzika, J Cvach, G D'Agostini, JB Dainton, F Dal Corso, K Daum, M Deák, Y De Boer, J De Favereau

Abstract:

Events with at least two high transverse momentum leptons (electrons or muons) are studied using the H1 and ZEUS detectors at HERA with an integrated luminosity of 0.94 fb-1. The observed numbers of events are in general agreement with the Standard Model predictions. Seven di- and tri-lepton events are observed in e+p collision data with a scalar sum of the lepton transverse momenta above 100GeV while 1.94 ± 0.17 events are expected. Such events are not observed in e-p collisions for which 1.19 ± 0.12 are predicted. Total visible and differential di-electron and di-muon photoproduction cross sections are extracted in a restricted phase space dominated by photon-photon collisions. © SISSA 2009.

Measurement of the longitudinal proton structure function at HERA

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 682:1 (2009) 8-22

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, 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

Abstract:

The reduced cross sections for ep deep inelastic scattering have been measured with the ZEUS detector at HERA at three different centre-of-mass energies, 318, 251 and 225 GeV. From the cross sections, measured double differentially in Bjorken x and the virtuality, Q ², the proton structure functions F L and F 2 have been extracted in the region 5 × 10 ^{- 4} < x < 0.007 and 20 < Q ² < 130 GeV ². © 2009 Elsevier B.V.

The LCFIVertex package: Vertexing, flavour tagging and vertex charge reconstruction with an ILC vertex detector

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 610:2 (2009) 573-589

Authors:

D Bailey, E Devetak, M Grimes, K Harder, S Hillert, D Jackson, T Pinto Jayawardena, B Jeffery, T Lastovicka, C Lynch, V Martin, R Walsh, P Allport, Y Banda, C Buttar, A Cheplakov, D Cussans, C Damerell, N De Groot, J Fopma, B Foster, S Galagedera, R Gao, A Gillman, J Goldstein, T Greenshaw, R Halsall, B Hawes, K Hayrapetyan, H Heath, J John, E Johnson, N Kundu, A Laing, G Lastovicka-Medin, W Lau, Y Li, A Lintern, S Mandry, P Murray, A Nichols, A Nomerotski, R Page, C Parkes, C Perry, V O'Shea, A Sopczak, K Stefanov, H Tabassam, S Thomas, T Tikkanen, R Turchetta, M Tyndel, J Velthuis, G Villani, T Wijnen, T Woolliscroft, S Worm, S Yang, Z Zhang

Abstract:

The precision measurements envisaged at the International Linear Collider (ILC) depend on excellent instrumentation and reconstruction software. The correct identification of heavy flavour jets, placing unprecedented requirements on the quality of the vertex detector, will be central for the ILC programme. This paper describes the LCFIVertex software, which provides tools for vertex finding and for identification of the flavour and charge of the leading hadron in heavy flavour jets. These tools are essential for the ongoing optimisation of the vertex detector design for linear colliders such as the ILC. The paper describes the algorithms implemented in the LCFIVertex package as well as the scope of the code and its performance for a typical vertex detector design. Crown Copyright © 2009.

Scaled momentum distributions of charged particles in dijet photoproduction at HERA

Journal of High Energy Physics 2009:8 (2009)

Authors:

O Behnke, J Behr, U Behrens, C Blohm, K Borras, D Bot, R Ciesielski, N Coppola, S Fang, A Geiser, P Gölttlicher, 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, R Mankel, IA Melzer-Pellmann, S Miglioranzi, A Montanari, T Namsoo, D Notz, A Parenti, P Roloff, I Rubinsky, U Schneekloth, A Spiridonov, D Szuba, J Szuba, T Theedt, J Tomaszewska, G Wolf, K Wrona, AG Yagües-Molina, C Youngman, W Zeuner, 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

Abstract:

The scaled momentum distributions of charged particles in jets have been measured for dijet photoproduction with the ZEUS detector at HERA using an integrated luminosity of 359 pb^-1. The distributions are compared to predictions based on perturbative QCD carried out in the framework of the modified leading-logarithmic approximation (MLLA) and assuming local parton-hadron duality (LPHD). The universal MLLA scale, Λeff, and the LPHD parameter, κ^ch, are extracted. © SISSA 2009.

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.

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