Time-resolved plasma temperature measurements in a laser-triggered hydrogen-filled capillary discharge waveguide

Plasma Sources Science and Technology 20:5 (2011)

Authors:

CJ Woolley, K O'Keeffe, HK Chung, SM Hooker

Abstract:

Temporally resolved, spatially integrated measurements of the temperature of the plasma channel formed by a hydrogen-filled discharge capillary waveguide are presented. Plasma temperatures of 4-7 eV are measured for peak discharge currents between 80 and 150 A. It is demonstrated that laser-triggering the capillary discharge enables capillary discharges with a peak current as low as 23 A to be driven, reducing the plasma temperature to approximately 3 eV. This plasma temperature meets the requirements of a recently proposed soft x-ray recombination laser. © 2011 IOP Publishing Ltd.

Simulation of free-electron lasers seeded with broadband radiation

Physical Review Special Topics - Accelerators and Beams 14:6 (2011)

Authors:

SI Bajlekov, WM Fawley, CB Schroeder, R Bartolini, SM Hooker

Abstract:

The longitudinal coherence of free-electron laser (FEL) radiation can be enhanced by seeding the FEL with high harmonics of an optical laser pulse. The radiation produced by high-harmonic generation (HHG), however, has a fast-varying temporal profile that can violate the slowly varying envelope approximation and limited frequency window that is employed in conventional free-electron laser simulation codes. Here we investigate the implications of violating this approximation on the accuracy of simulations. On the basis of both analytical considerations and 1D numerical studies, it is concluded that, for most realistic scenarios, conventional FEL codes are capable of accurately simulating the FEL process even when the seed radiation violates the slowly varying envelope approximation. We additionally discuss the significance of filtering the harmonic content of broadband HHG seeds. © 2011 American Physical Society.

Measurement of heavy-quark jet photoproduction at HERA

(2011)

Authors:

ZEUS Collaboration, H Abramowicz, I Abt, L Adamczyk, M Adamus, R Aggarwal, S Antonelli, P Antonioli, A Antonov, M Arneodo, V Aushev, Y Aushev, O Bachynska, A Bamberger, AN Barakbaev, G Barbagli, G Bari, F Barreiro, N Bartosik, D Bartsch, M Basile, O Behnke, J Behr, U Behrens, L Bellagamba, A Bertolin, S Bhadra, M Bindi, C Blohm, V Bokhonov, T Bołd, O Bolilyi, K Bondarenko, EG Boos, K Borras, D Boscherini, D Bot, I Brock, E Brownson, R Brugnera, N Brümmer, A Bruni, G Bruni, B Brzozowska, PJ Bussey, B Bylsma, A Caldwell, M Capua, R Carlin, CD Catterall, S Chekanov, J Chwastowski, J Ciborowski, R Ciesielski, L Cifarelli, F Cindolo, A Contin, AM Cooper-Sarkar, N Coppola, M Corradi, F Corriveau, M Costa, G D'Agostini, F Dal Corso, J del Peso, RK Dementiev, S De Pasquale, M Derrick, RCE Devenish, D Dobur, BA Dolgoshein, G Dolinska, AT Doyle, V Drugakov, LS Durkin, S Dusini, Y Eisenberg, PF Ermolov, A Eskreys, S Fang, S Fazio, J Ferrando, MI Ferrero, J Figiel, M Forrest, B Foster, S Fourletov, G Gach, A Galas, E Gallo, A Garfagnini, A Geiser, I Gialas, LK Gladilin, D Gladkov, C Glasman, O Gogota, Yu A Golubkov, P Göttlicher, I Grabowska-Bołd, J Grebenyuk, I Gregor, G Grigorescu, G Grzelak, O Gueta, C Gwenlan, T Haas, W Hain, R Hamatsu, JC Hart, H Hartmann, G Hartner, E Hilger, D Hochman, R Hori, K Horton, A Hüttmann, ZA Ibrahim, Y Iga, R Ingbir, M Ishitsuka, H-P Jakob, F Januschek, M Jimenez, TW Jones, M Jüngst, I Kadenko, B Kahle, B Kamaluddin, S Kananov, T Kanno, U Karshon, F Karstens, II Katkov, M Kaur, P Kaur, A Keramidas, LA Khein, JY Kim, D Kisielewska, S Kitamura, R Klanner, U Klein, E Koffeman, P Kooijman, Ie Korol, IA Korzhavina, A Kotański, U Kötz, H Kowalski, P Kulinski, O Kuprash, M Kuze, A Lee, BB Levchenko, A Levy, V Libov, S Limentani, TY Ling, M Lisovyi, E Lobodzinska, W Lohmann, B Löhr, E Lohrmann, KR Long, A Longhin, D Lontkovskyi, O Yu Lukina, P Łużniak, J Maeda, S Magill, I Makarenko, J Malka, R Mankel, A Margotti, G Marini, JF Martin, A Mastroberardino, MCK Mattingly, I-A Melzer-Pellmann, S Mergelmeyer, S Miglioranzi, F Mohamad Idris, V Monaco, A Montanari, JD Morris, K Mujkic, B Musgrave, K Nagano, T Namsoo, R Nania, D Nicholass, A Nigro, Y Ning, T Nobe, U Noor, D Notz, RJ Nowak, AE Nuncio-Quiroz, BY Oh, N Okazaki, K Oliver, K Olkiewicz, Yu Onishchuk, K Papageorgiu, A Parenti, E Paul, JM Pawlak, B Pawlik, PG Pelfer, A Pellegrino, W Perlanski, H Perrey, K Piotrzkowski, P Plucinski, NS Pokrovskiy, A Polini, AS Proskuryakov, M Przybycień, A Raval, DD Reeder, B Reisert, Z Ren, J Repond, YD Ri, A Robertson, P Roloff, E Ron, I Rubinsky, M Ruspa, R Sacchi, A Salii, U Samson, G Sartorelli, AA Savin, DH Saxon, M Schioppa, S Schlenstedt, P Schleper, WB Schmidke, U Schneekloth, V Schönberg, T Schörner-Sadenius, J Schwartz, F Sciulli, LM Shcheglova, R Shehzadi, S Shimizu, I Singh, IO Skillicorn, W Słomiński, WH Smith, V Sola, A Solano, D Son, V Sosnovtsev, A Spiridonov, H Stadie, L Stanco, A Stern, TP Stewart, A Stifutkin, P Stopa, S Suchkov, G Susinno, L Suszycki, J Sztuk-Dambietz, D Szuba, J Szuba, AD Tapper, E Tassi, J Terrón, T Theedt, H Tiecke, K Tokushuku, O Tomalak, J Tomaszewska, T Tsurugai, M Turcato, T Tymieniecka, C Uribe-Estrada, M Vázquez, A Verbytskyi, O Viazlo, NN Vlasov, O Volynets, R Walczak, WAT Wan Abdullah, JJ Whitmore, J Whyte, L Wiggers, M Wing, M Wlasenko, G Wolf, H Wolfe, K Wrona, AG Yagües-Molina, S Yamada, Y Yamazaki, R Yoshida, C Youngman, AF Żarnecki, L Zawiejski, O Zenaiev, W Zeuner, BO Zhautykov, N Zhmak, C Zhou, A Zichichi, M Zolko, DS Zotkin, Z Zulkapli

Measurement of the energy dependence of the total photon-proton cross section at HERA

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 697:3 (2011) 184-193

Authors:

H Abramowicz, I Abt, L Adamczyk, M Adamus, R Aggarwal, S Antonelli, P Antonioli, A Antonov, M Arneodo, V Aushev, Y Aushev, O Bachynska, A Bamberger, AN Barakbaev, G Barbagli, G Bari, F Barreiro, D Bartsch, M Basile, O Behnke, J Behr, U Behrens, L Bellagamba, A Bertolin, S Bhadra, M Bindi, C Blohm, V Bokhonov, T Bold, EG Boos, K Borras, D Boscherini, D Bot, SK Boutle, I Brock, E Brownson, R Brugnera, N Brümmer, A Bruni, G Bruni, B Brzozowska, PJ Bussey, JM Butterworth, B Bylsma, A Caldwell, M Capua, R Carlin, CD Catterall, S Chekanov, J Chwastowski, J Ciborowski, R Ciesielski, L Cifarelli, F Cindolo, A Contin, AM Cooper-Sarkar, N Coppola, M Corradi, F Corriveau, M Costa, G D'Agostini, F Dal Corso, J del Peso, RK Dementiev, S De Pasquale, M Derrick, RCE Devenish, D Dobur, BA Dolgoshein, G Dolinska, AT Doyle, V Drugakov, LS Durkin, S Dusini, Y Eisenberg, PF Ermolov, A Eskreys, S Fang, S Fazio, J Ferrando, MI Ferrero, J Figiel, M Forrest, B Foster, S Fourletov, G Gach, A Galas, E Gallo, A Garfagnini, A Geiser, I Gialas, LK Gladilin, D Gladkov, C Glasman, O Gogota, Y Golubkov, P Göttlicher, I Grabowska-Bold, J Grebenyuk, I Gregor

Abstract:

The energy dependence of the photon-proton total cross section, σtotγp, was determined from e+p scattering data collected with the ZEUS detector at HERA at three values of the center-of-mass energy, W, of the γp system in the range 194

Study of tau-pair production at HERA

Journal of High Energy Physics 2011:2 (2011)

Authors:

A Levy, H Abramowicz, L Adamczyk, M Adamus, R Aggarwal, S Antonelli, P Antonioli, A Antonov, M Arneodo, V Aushev, Y Aushev, O Bachynska, A Bamberger, AN Barakbaev, G Barbagli, G Bari, F Barreiro, N Bartosik, D Bartsch, M Basile, O Behnke, J Behr, U Behrens, L Bellagamba, A Bertolin, S Bhadra, M Bindi, C Blohm, V Bokhonov, T Bold, O Bolilyi, EG Boos, K Borras, D Boscherini, D Bot, SK Boutle, I Brock, E Brownson, R Brugnera, N Brümmer, A Bruni, G Bruni, B Brzozowska, PJ Bussey, JM Butterworth, B Bylsma, A Caldwell, M Capua, R Carlin, CD Catterall, S Chekanov, J Chwastowski, J Ciborowski, R Ciesielski, L Cifarelli, F Cindolo, A Contin, AM Cooper-Sarkar, N Coppola, M Corradi, F Corriveau, M Costa, G D'Agostini, F Dal Corso, J Dal Peso, RK Dementiev, S De Pasquale, M Derrick, RCE Devenish, D Dobur, BA Dolgoshein, G Dolinska, AT Doyle, V Drugakov, LS Durkin, S Dusini, Y Eisenberg, PF Ermolov, A Eskreys, S Fang, S Fazio, J Ferrando, MI Ferrero, J Figiel, M Forrest, B Foster, S Fourletov, G Gach, A Galas, E Gallo, A Garfagnini, A Geiser, I Gialas, LK Gladilin, D Gladkov, C Glasman, O Gogota, YA Golubkov, P Göttlicher, I Grabowska-Bołd

Abstract:

A study of events containing two tau leptons with high transverse momentum has been performed with the ZEUS detector at HERA, using a data sample corresponding to an integrated luminosity of 0.33 fb-1. The tau candidates were identified from their decays into electrons, muons or hadronic jets. The number of tau-pair candidates has been compared with the prediction from the Standard Model, where the largest contribution is expected from Bethe-Heitler processes. The total visible cross section was extracted. Standard Model expectations agree well with the measured distributions, also at high invariant mass of the tau pair.