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High-ET dijet photoproduction at HERA

Physical Review D - Particles, Fields, Gravitation and Cosmology 76:7 (2007)

Authors:

S Chekanov, M Derrick, S Magill, B Musgrave, D Nicholass, J Repond, R Yoshida, MCK Mattingly, M Jechow, N Pavel, AG Yagües Molina, S Antonelli, P Antonioli, G Bari, M Basile, L Bellagamba, M Bindi, D Boscherini, A Bruni, G Bruni, L Cifarelli, F Cindolo, A Contin, M Corradi, S De Pasquale, G Iacobucci, A Margotti, R Nania, A Polini, G Sartorelli, A Zichichi, D Bartsch, I Brock, S Goers, H Hartmann, E Hilger, HP Jakob, M Jüngst, OM Kind, AE Nuncio-Quiroz, E Paul, R Renner, 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, KJ Ma, 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, V Adler, U Behrens, I Bloch, C Blohm, A Bonato, K Borras, R Ciesielski, N Coppola, A Dossanov, V Drugakov, J Fourletova, A Geiser, D Gladkov, P Göttlicher, J Grebenyuk, I Gregor, T Haas, W Hain, C Horn, A Hüttmann

Abstract:

The cross section for high-ET dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 81.8pb-1. The events were required to have a virtuality of the incoming photon, Q2, of less than 1GeV2 and a photon-proton center-of-mass energy in the range 14220GeV and ETjet2>15GeV and pseudorapidity (with respect to the proton beam direction) requirements of -1<ηjet1,2<3, with at least one of the jets satisfying -1<ηjet<2.5. The measurements show sensitivity to the parton distributions in the photon and proton and to effects beyond next-to-leading order in QCD. Hence these data can be used to constrain further the parton densities in the proton and photon. © 2007 The American Physical Society.
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The optical alignment system of the ZEUS microvertex detector

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 580:3 (2007) 1227-1242

Authors:

K Korcsak-Gorzo, G Grzelak, K Oliver, M Dawson, R Devenish, J Ferrando, T Matsushita, P Shield, R Walczak

Abstract:

The laser alignment system of the ZEUS microvertex detector is described. The detector was installed in 2001 as part of an upgrade programme in preparation for the second phase of electron-proton physics at the HERA collider. The alignment system monitors the position of the vertex detector support structure with respect to the central tracking detector using semi-transparent amorphous-silicon sensors and diode lasers. The system is fully integrated into the general environmental monitoring of the ZEUS detector and data has been collected over a period of 5 years. The primary aim of defining periods of stability for track-based alignment has been achieved and the system is able to measure movements of the support structure to a precision around 10 μ m. © 2007 Elsevier B.V. All rights reserved.
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Bright quasi-phase-matched soft-X-ray harmonic radiation from argon ions

Physical Review Letters 99:14 (2007)

Authors:

M Zepf, B Dromey, M Landreman, P Foster, SM Hooker

Abstract:

Selective enhancement (>103) of harmonics extending to the water window (∼4nm) generated in an argon gas filled straight bore capillary waveguide is demonstrated. This enhancement is in good agreement with modeling which indicates that multimode quasi-phase-matching is achieved by rapid axial intensity modulations caused by beating between the fundamental and higher-order capillary modes. Substantial pulse energies (>10nJ per pulse per harmonic order) at wavelengths beyond the carbon K edge (∼4.37nm, ∼284eV) up to ∼360eV are observed from argon ions for the first time. © 2007 The American Physical Society.
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The design and performance of the ZEUS Micro Vertex detector

(2007)

Authors:

A Polini, I Brock, S Goers, A Kappes, UF Katz, E Hilger, J Rautenberg, A Weber, A Mastroberardino, E Tassi, V Adler, LAT Bauerdick, I Bloch, T Haas, U Klein, U Koetz, G Kramberger, E Lobodzinska, R Mankel, J Ng, D Notz, MC Petrucci, B Surrow, G Watt, C Youngman, W Zeuner, C Coldewey, R Heller, E Gallo, T Carli, V Chiochia, D Dannheim, E Fretwurst, A Garfagnini, R Klanner, B Koppitz, J Martens, M Milite, K Tokushuku, I Redondo, H Boterenbrood, E Koffeman, P Kooijman, E Maddox, H Tiecke, M Vazquez, J Velthuis, L Wiggers, RCE Devenish, M Dawson, J Ferrando, G Grzelak, K Korcsak-Gorzo, T Matsushita, K Oliver, P Shield, R Walczak, A Bertolin, E Borsato, R Carlin, F Dal Corso, A Longhin, M Turcato, T Fusayasu, R Hori, T Kohno, S Shimizu, HE Larsen, R Sacchi, A Staiano, M Arneodo, M Ruspa, J Butterworth, C Gwenlan, J Fraser, D Hayes, M Hayes, J Lane, G Nixon, M Postranecky, M Sutton, M Warren
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Bose-Einstein correlations of charged and neutral kaons in deep inelastic scattering at HERA

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 652:1 (2007) 1-12

Authors:

S Chekanov, M Derrick, S Magill, B Musgrave, D Nicholass, J Repond, R Yoshida, MCK Mattingly, M Jechow, N Pavel, AG Yagües Molina, S Antonelli, P Antonioli, G Bari, M Basile, L Bellagamba, M Bindi, D Boscherini, A Bruni, G Bruni, L Cifarelli, F Cindolo, A Contin, M Corradi, S De Pasquale, G Iacobucci, A Margotti, R Nania, A Polini, G Sartorelli, A Zichichi, D Bartsch, I Brock, S Goers, H Hartmann, E Hilger, HP Jakob, M Jüngst, OM Kind, AE Nuncio-Quiroz, E Paul, R Renner, U Samson, V Schönberg, R Shehzadi, M Wlasenko, NH Brook, GP Heath, JD Morris, T Namsoo, M Capua, S Fazio, A Mastroberardino, M Schioppa, G Susinno, E Tassi, JY Kim, KJ Ma, 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, V Adler, U Behrens, I Bloch, C Blohm, A Bonato, K Borras, R Ciesielski, N Coppola, A Dossanov, V Drugakov, J Fourletova, A Geiser, D Gladkov, P Göttlicher, J Grebenyuk, I Gregor, T Haas, W Hain, C Horn

Abstract:

Bose-Einstein correlations of charged and neutral kaons have been measured in e ± p deep inelastic scattering with an integrated luminosity of 121   pb -1 using the ZEUS detector at HERA. The two-particle correlation function was studied as a function of the four-momentum difference of the kaon pairs, Q 12 = sqrt(- (p 1 - p 2) 2), assuming a Gaussian shape for the particle source. The values of the radius of the production volume, r, and of the correlation strength, λ, were obtained for both neutral and charged kaons. The radii for charged and neutral kaons are similar and are consistent with those obtained at LEP. © 2007 Elsevier B.V. All rights reserved.
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