The Q2 evolution of the hadronic photon structure function F2γ at LEP

PHYSICS LETTERS B 447:1-2 (1999) 147-156

Authors:

M Acciarri, P Achard, O Adriani, M Aguilar-Benitez, J Alcaraz, G Alemanni, J Allaby, A Aloisio, MG Alviggi, G Ambrosi, H Anderhub, VP Andreev, T Angelescu, F Anselmo, A Arefiev, T Azemoon, T Aziz, P Bagnaia, L Baksay, A Balandras, RC Ball, S Banerjee, S Banerjee, K Banicz, A Barczyk, R Barillère, L Barone, P Bartalini, M Basile, R Battiston, A Bay, F Becattini, U Becker, F Behner, J Berdugo, P Berges, B Bertucci, BL Betev, S Bhattacharya, M Biasini, A Biland, GM Bilei, JJ Blaising, SC Blyth, GJ Bobbink, R Bock, A Böhm, L Boldizsar, B Borgia, D Bourilkov, M Bourquin, S Braccini, JG Branson, V Brigljevic, F Brochu, IC Brock, A Buffini, A Buijs, JD Burger, WJ Burger, J Busenitz, A Button, XD Cai, M Campanelli, M Capell, GC Romeo, G Carlino, AM Cartacci, J Casaus, G Castellini, F Cavallari, N Cavallo, C Cecchi, M Cerrada, F Cesaroni, M Chamizo, YH Chang, UK Chaturvedi, M Chemarin, A Chen, G Chen, GM Chen, HF Chen, HS Chen, X Chereau, G Chiefari, L Cifarelli, F Cindolo, C Civinini, I Clare, R Clare, G Coignet, AP Colijn, N Colino, S Costantini, F Cotorobai, B de la Cruz, A Csilling, TS Dai, JA van Dalen, R D'Alessandro, R de Asmundis, P Deglon, A Degré, K Deiters, D della Volpe, P Denes, F DeNotaristefani, A De Salvo, M Diemoz, D van Dierendonck, F Di Lodovico, C Dionisi, M Dittmar, A Dominguez, A Doria, MT Dova, D Duchesneau, D Dufournand, P Duinker, I Duran, S Easo, H El Mamouni, A Engler, FJ Eppling, FC Erné, P Extermann, M Fabre, R Faccini, MA Falagan, S Falciano, A Favara, J Fay, O Fedin, M Felcini, T Ferguson, F Ferroni, H Fesefeldt, E Fiandrini, JH Field, F Filthaut, PH Fisher, I Fisk, G Forconi, L Fredj, K Freudenreich, C Furetta, Y Galaktionov, SN Ganguli, P Garcia-Abia, M Gataullin, SS Gau, S Gentile, N Gheordanescu, S Giagu, S Goldfarb, ZF Gong, G Gratta, MW Gruenewald, R van Gulik, VK Gupta, A Gurtu, LJ Gutay, D Haas, B Hartmann, A Hasan, D Hatzifotiadou, T Hebbeker, A Hervé, P Hidas, J Hirschfelder, H Hofer, G Holzner, H Hoorani, SR Hou, I Iashvili, BN Jin, LW Jones, P de Jong, I Josa-Mutuberría, RA Khan, D Kamrad, JS Kapustinsky, M Kaur, MN Kienzle-Focacci, D Kim, DH Kim, JK Kim, SC Kim, WW Kinnison, A Kirkby, D Kirkby, J Kirkby, D Kiss, W Kittel, A Klimentov, AC König, A Kopp, I Korolko, V Koutsenko, RW Kraemer, W Krenz, A Kunin, P Lacentre, PL de Guevara, I Laktineh, G Landi, C Lapoint, K Lassila-Perini, P Laurikainen, A Lavorato, M Lebeau, A Lebedev, P Lebrun, P Lecomte, P Lecoq, P Le Coultre, HJ Lee, JM Le Goff, R Leiste, E Leonardi, P Levtchenko, C Li, CH Lin, WT Lin, FL Linde, L Lista, ZA Liu, W Lohmann, E Longo, W Lu, YS Lu, K Lübelsmeyer, C Luci, D Luckey, L Luminari, W Lustermann, WG Ma, M Maity, G Majumder, L Malgeri, A Malinin, C Maña, D Mangeol, P Marchesini, G Marian, JP Martin, F Marzano, GGG Massaro, K Mazumdar, RR McNeil, S Mele, L Merola, M Meschini, WJ Metzger, M von der Mey, D Migani, A Mihul, H Milcent, G Mirabelli, J Mnich, P Molnar, B Monteleoni, T Moulik, R Mount, GS Muanza, F Muheim, AJM Muijs, S Nahn, M Napolitano, F Nessi-Tedaldi, H Newman, T Niessen, A Nippe, A Nisati, H Nowak, YD Oh, G Organtini, R Ostonen, C Palomares, D Pandoulas, S Paoletti, P Paolucci, HK Park, IH Park, G Pascale, G Passaleva, S Patricelli, T Paul, M Pauluzzi, C Paus, F Pauss, D Peach, M Pedace, YJ Pei, S Pensotti, D Perret-Gallix, B Petersen, S Petrak, A Pevsner, D Piccolo, M Pieri, PA Piroué, E Pistolesi, V Plyaskin, M Pohl, V Pojidaev, H Postema, J Pothier, N Produit, D Prokofiev, J Quartieri, G Rahal-Callot, N Raja, PG Raacoita, M Rattaggi, G Raven, P Razis, D Ren, M Rescigno, S Reucroft, T van Rhee, S Riemann, K Riles, A Robohm, J Rodin, BP Roe, L Romero, S Rosier-Lees, S Roth, JA Rubio, D Ruschmeier, H Rykaczewski, S Sakar, J Salicio, E Sanchez, MP Sanders, ME Sarakinos, C Schäfer, V Schegelsky, S Schmidt-Kaerst, D Schmitz, N Scholz, H Schopper, DJ Schotanus, J Schwenke, G Schwering, C Sciacca, D Sciarrino, L Servoli, S Shevchenko, N Shivarov, V Shoutko, J Shukla, E Shumilov, A Shvorob, T Siedenburg, D Son, B Smith, P Spillantini, M Steuer, DP Stickland, A Stone, H Stone, B Stoyanov, A Straessner, K Sudhakar, G Sultanov, LZ Sun, H Suter, JD Swain, Z Szillasi, XW Tang, L Tauscher, L Taylor, C Timmermans, SCC Ting, SM Ting, SC Tonwar, J Tóth, C Tully, KL Tung, Y Uchida, J Ulbricht, E Valente, G Vesztergombi, I Vetlitsky, G Viertel, S Villa, M Vivargent, S Vlachos, H Vogel, H Vogt, I Vorobiev, AA Vorobyov, A Vorvolakos, M Wadhwa, W Wallraff, JC Wang, XL Wang, ZM Wang, A Weber, SX Wu, S Wynhoff, ZZ Xu, BZ Yang, CG Yang, HJ Yang, M Yang, JB Ye, SC Yeh, JM You, A Zalite, Y Zalite, P Zemp, Y Zeng, ZP Zhang, GY Zhu, RY Zhu, A Zichichi, F Ziegler, G Zilizi

A 40 MHz-pipelined trigger for K-0 -> 2 pi(0) decays for the CERN NA48 experiment

NUCL INSTRUM METH A 419:2-3 (1998) 695-700

Authors:

G Fischer, C Avanzini, GD Barr, P Calafiura, M Cirilli, F Costantini, D Cundy, H Dibon, F Formenti, B Gorini, B Hallgren, W Iwanski, M Jeitler, P Kapusta, F Laico, G Laverriere, G Magazzu, M Markytan, I Mikulec, F Morsani, G Neuhofer, M Pernicka, GM Pierazzini, M Porcu, D Rizzi, F Rossi, M Sozzi, A Taurok, R Tripiccione, M Velasco, O Vossnack, H Wahl, M Ziolkowski

Abstract:

The "neutral" trigger system for the selection of K-o --> 2 pi(o) --> 4 gamma decays of the NA48 CP-violation experiment is described. The trigger system has been implemented in a 40 MHz "dead-time free" pipeline to allow large rate reduction and high-trigger efficiency. The trigger decision is based on the information from 13340 cells of the electro-magnetic calorimeter. Every 25 ns the energy, the centre of gravity, the kaon lifetime and the number of peaks in calorimeter projections are calculated in the trigger. The pipeline system is described and the performance of the trigger during the 1997 data-taking period is discussed. (C) 1998 Published by Elsevier Science B.V. All rights reserved.

The NA48 LKr calorimeter digitizer electronics chain

NUCL INSTRUM METH A 419:2-3 (1998) 680-685

Authors:

B Hallgren, F Bal, G Barr, P Buchholz, A Ceccucci, F Formenti, W Funk, A Gianoli, Y Kozhevnikov, A Lacourt, G Laverriere, M Martini, A Papi, M Sozzi, JC Tarle, O Vossnack, H Wahl

Abstract:

The 13500 channels of the NA48 liquid-krypton electromagnetic calorimeter readout electronics were put into operation in 1997. The digitizer electronics employs a new gain switching technique that expands the dynamic range of a standard 10-bit ADC to 14 bits at 40 MHz sampling rate employing a custom-developed integrated circuit (KRYPTON). The KRYPTON has been fabricated in 1.2 mu m BiCMOS technology and was successfully developed together with industry on a short timescale. The performance and the experience from the first year of the operation of the liquid-krypton calorimeter electronics will also be briefly discussed. (C) 1998 Elsevier Science B.V. All rights reserved.

Test beam results from the CLEO III LiF-TEA RICH

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment Elsevier 419:2-3 (1998) 577-583

Authors:

M Artuso, F Azfar, A Efimov, S Kopp, R Mountain, S Schuh, T Skwarnicki, S Stone, G Viehhauser, S Anderson, A Smith, Y Kubota, E Lipeles, T Coan, J Staeck, V Fadeyev, I Volobouev, J Ye

Probing hard color-singlet exchange in pp̄ collisions at √s = 630 GeV and 1800 GeV

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 440:1-2 (1998) 189-202

Authors:

B Abbott, M Abolins, V Abramov, BS Acharya, I Adam, DL Adams, M Adams, S Ahn, H Aihara, GA Alves, N Amos, EW Anderson, R Astur, MM Baarmand, VV Babintsev, L Babukhadia, A Baden, B Baldin, S Banerjee, J Bantly, E Barberis, P Baringer, JF Bartlett, A Belyaev, SB Beri, I Bertram, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, N Biswas, G Blazey, S Blessing, P Bloom, A Boehnlein, NI Bojko, F Borcherding, C Boswell, A Brandt, R Breedon, R Brock, A Bross, D Buchholz, VS Burtovoi, JM Butler, W Carvalho, D Casey, Z Casilum, H Castilla-Valdez, D Chakraborty, SM Chang, SV Chekulaev, W Chen, S Choi, S Chopra, BC Choudhary, JH Christenson, M Chung, D Claes, AR Clark, WG Cobau, J Cochran, L Coney, WE Cooper, C Cretsinger, D Cullen-Vidal, MAC Cummings, D Cutts, OI Dahl, K Davis, K De, K Del Signore, M Demarteau, D Denisov, SP Denisov, HT Diehl, M Diesburg, G di Loreto, P Draper, Y Ducros, LV Dudko, SR Dugad, A Dyshkant, D Edmunds, J Ellison, VD Elvira, R Engelmann, S Eno, G Eppley, P Ermolov, OV Eroshin, VN Evdokimov, T Fahland, MK Fatyga, S Feher, D Fein, T Ferbel, G Finocchiaro, HE Fisk, Y Fisyak

Abstract:

We present results on dijet production via hard color-singlet exchange in proton-antiproton collisions at √s = 630 GeV and 1800 GeV using the DØ detector. The fraction of dijet events produced via color-singlet exchange is measured as a function of jet transverse energy, separation in pseudorapidity between the two highest transverse energy jets, and proton-antiproton center-of-mass energy. The results are consistent with a color-singlet fraction that increases with an increasing fraction of quark-initiated processes and inconsistent with two-gluon models for the hard color-singlet. © 1998 Published by Elsevier Science B.V. All rights reserved.