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Search for excited quarks in ep collisions at HERA

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 678:4 (2009) 335-343

Authors:

FD Aaron, C Alexa, K Alimujiang, V Andreev, B Antunovic, A Asmone, S Backovic, A Baghdasaryan, E Barrelet, W Bartel, K Begzsuren, A Belousov, JC Bizot, V Boudry, I Bozovic-Jelisavcic, J Bracinik, G Brandt, M Brinkmann, V Brisson, D Bruncko, A Bunyatyan, G Buschhorn, L Bystritskaya, AJ Campbell, KBC Avila, F Cassol-Brunner, K Cerny, V Cerny, V Chekelian, A Cholewa, JG Contreras, JA Coughlan, G Cozzika, J Cvach, JB Dainton, K Daum, M Deák, Y de Boer, B Delcourt, M Del Degan, J Delvax, A De Roeck, EA De Wolf, C Diaconu, V Dodonov, A Dossanov, A Dubak, G Eckerlin, V Efremenko, S Egli, A Eliseev, E Elsen, A Falkiewicz, PJW Faulkner, L Favart, A Fedotov, R Felst, J Feltesse, J Ferencei, DJ Fischer, M Fleischer, A Fomenko, E Gabathuler, J Gayler, S Ghazaryan, A Glazov, I Glushkov, L Goerlich, N Gogitidze, M Gouzevitch, C Grab, T Greenshaw, BR Grell, G Grindhammer, S Habib, D Haidt, C Helebrant, RCW Henderson, E Hennekemper, H Henschel, M Herbst, G Herrera, M Hildebrandt, KH Hiller, D Hoffmann, R Horisberger, T Hreus, M Jacquet, ME Janssen, X Janssen, V Jemanov, L Jönsson, AW Jung, H Jung, M Kapichine, J Katzy, IR Kenyon, C Kiesling, M Klein, C Kleinwort

Abstract:

A search for excited quarks is performed using the full e ± p data sample collected by the H1 experiment at HERA, corresponding to a total integrated luminosity of 475   pb - 1. The electroweak decays of excited quarks q * → q γ, q * → q Z and q * → q W with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for first generation excited quark production is found. Mass dependent exclusion limits on q * production cross sections and on the ratio f / Λ of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited quark searches. © 2009 Elsevier B.V.
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Deep inelastic scattering with leading protons or large rapidity gaps at HERA

Nuclear Physics B 816:1-2 (2009) 1-61

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, G Cara Romeo, F Cindolo, M Corradi, G Iacobucci, A Margotti, T Massam, R Nania, A Polini, S Antonelli, M Basile, M Bindi, L Cifarelli, A Contin, F Palmonari, 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, 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, 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

Abstract:

The dissociation of virtual photons, γ{star operator} p → X p, in events with a large rapidity gap between X and the outgoing proton, as well as in events in which the leading proton was directly measured, has been studied with the ZEUS detector at HERA. The data cover photon virtualities Q2 > 2   GeV2 and γ{star operator} p centre-of-mass energies 40 < W < 240   GeV, with MX > 2   GeV, where MX is the mass of the hadronic final state, X. Leading protons were detected in the ZEUS leading proton spectrometer. The cross section is presented as a function of t, the squared four-momentum transfer at the proton vertex and Φ, the azimuthal angle between the positron scattering plane and the proton scattering plane. It is also shown as a function of Q2 and xP, the fraction of the proton's momentum carried by the diffractive exchange, as well as β, the Bjorken variable defined with respect to the diffractive exchange. © 2009 Elsevier B.V.
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Measurement of beauty production from dimuon events at HERA

Journal of High Energy Physics 2009:2 (2009)

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, B Kamaluddin, WAT Wan Abdullah, Y Ning, Z Ren, F Sciulli, J Chwastowski, A Eskreys, J Figiel, A Galas, K Olkiewicz, P Stopa, L Zawiejski, L Adamczyk, T Bold, I Grabowska-Bold, D Kisielewska, J Lukasik, M Przybycien, L Suszycki, A Kotanski, WS Lominski, O Behnke, U Behrens, I Bloch, C Blohm, A Bonato, K Borras, D Bot, R Ciesielski, N Coppola, S Fang, J Fourletova, A Geiser, P Gottlicher, J Grebenyuk, I Gregor, O Gutsche, T Haas, W Hain, A Huttmann, F Januschek, B Kahle, II Katkov, U Klein, U Kotz, H Kowalski

Abstract:

Beauty production in events containing two muons in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb-1. A low transverse-momentum threshold for muon identification, in combination with the large rapidity coverage of the ZEUS muon system, gives access to almost the full phase space for beauty production. The total cross section for beauty production in ep collisions at (s)1/2 = 318 GeV has been measured to be σtot(ep bX) = 13.9 1.5(stat.)+4.0-4.3(syst.)nb. Differential cross sections and a measurement of b correlations are also obtained, and compared to other beauty cross-section measurements, Monte Carlo models and next-to-leading-order QCD predictions. © 2009 SISSA.
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Measurement of charged current deep inelastic scattering cross sections with a longitudinally polarised electron beam at HERA

European Physical Journal C 61:2 (2009) 223-235

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:

Measurements of the cross sections for charged current deep inelastic scattering in e - p collisions with longitudinally polarised electron beams are presented. The measurements are based on a data sample with an integrated luminosity of 175 pb-1 collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is given for positively and negatively polarised electron beams. The differential cross-sections d σ/dQ 2, d σ/dx and d σ/dy are presented for Q 2>200 GeV2. The double-differential cross-section d 2 σ/dxdQ 2 is presented in the kinematic range 280
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Production of excited charm and charm-strange mesons at HERA

European Physical Journal C 60:1 (2009) 25-45

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 Capua, S Fazio, A Mastroberardino, M Schioppa, G Susinno, E Tassi, JY Kim, ZA Ibrahim, B Kamaluddin, WAT Wan Abdullah, Y Ning, Z Ren, F Sciulli, J Chwastowski, A Eskreys, J Figiel, A Galas, M Gil, K Olkiewicz, P Stopa, L Zawiejski, L Adamczyk, T Bołd, I Grabowska-Bołd, D Kisielewska, J Łukasik, M Przybycień, L Suszycki, A Kotański, W Słomiński, U Behrens, C Blohm, A Bonato, K Borras, 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, E Lobodzinska, B Löhr, R Mankel, IA Melzer-Pellmann, S Miglioranzi, A Montanari

Abstract:

The production of excited charm, D 1(2420)0 and D 2* (2460)0, and charm-strange, D s1(2536)±, mesons in ep collisions was measured with the ZEUS detector at HERA using an integrated luminosity of 126 pb -1. Masses, widths and helicity parameters were determined. The measured yields were converted to the rates of c quarks hadronising as a given excited charm meson and to the ratios of the dominant D 2* (2460)0 and D s1(2536) ± branching fractions. A search for the radially excited charm meson, D *(2640)±, was also performed. The results are compared with those measured previously and with theoretical expectations. © 2009 Springer-Verlag / Società Italiana di Fisica.
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