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Latest beam test results from RICH prototypes using hybrid photo detectors and multi anode PMTs

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 433:1 (1999) 159-163

Authors:

E Albrecht, M Alemi, G Barber, JH Bibby, NH Brook, A Duane, S Easo, L Eklund, V Gibson, T Gys, AW Halley, N Harnew, M John, D Piedigrossi, B Simmons, N Smale, P Teixeira-Dias, D Websdale, SA Wotton, K Wyllie

Abstract:

Beam tests were performed to investigate the performance of a prototype of the downstream ring imaging counter (RICH) of the LHCb using hybrid photodiodes and multi-anode photomultipliers. The Cerenkov angle resolution obtained for the three types of photodetectors tested agreed well with the expectations from simulations. Using 61-pixel hybrid photodiodes, a single photon resolution of 0.35 mrad was attained and the particle identification capability was demonstrated.
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Measurement of Charm Meson Lifetimes

Physical Review Letters American Physical Society (APS) 82:23 (1999) 4586-4590

Authors:

G Bonvicini, D Cinabro, R Greene, LP Perera, GJ Zhou, S Chan, G Eigen, E Lipeles, M Schmidtler, A Shapiro, WM Sun, J Urheim, AJ Weinstein, F Würthwein, DE Jaffe, G Masek, HP Paar, EM Potter, S Prell, V Sharma, DM Asner, A Eppich, J Gronberg, TS Hill, CM Korte, DJ Lange, RJ Morrison, HN Nelson, TK Nelson, D Roberts, H Tajima, BH Behrens, WT Ford, A Gritsan, H Krieg, J Roy, JG Smith, JP Alexander, R Baker, C Bebek, BE Berger, K Berkelman, V Boisvert, DG Cassel, DS Crowcroft, M Dickson, S von Dombrowski, PS Drell, DJ Dumas, KM Ecklund, R Ehrlich, AD Foland, P Gaidarev, L Gibbons, B Gittelman, SW Gray, DL Hartill, BK Heltsley, S Henderson, PI Hopman, N Katayama, DL Kreinick, T Lee, Y Liu, TO Meyer, NB Mistry, CR Ng, E Nordberg, M Ogg, JR Patterson, D Peterson, D Riley, A Soffer, JG Thayer, PG Thies, B Valant-Spaight, A Warburton, C Ward, M Athanas, P Avery, CD Jones, M Lohner, C Prescott, AI Rubiera, J Yelton, J Zheng, G Brandenburg, RA Briere, A Ershov, YS Gao, DY-J Kim, R Wilson, TE Browder, Y Li, JL Rodriguez, H Yamamoto, T Bergfeld, BI Eisenstein, J Ernst, GE Gladding, GD Gollin, RM Hans, E Johnson, I Karliner, MA Marsh, M Palmer, C Plager, C Sedlack, M Selen, JJ Thaler, J Williams, KW Edwards, A Bellerive, R Janicek, PM Patel, AJ Sadoff, R Ammar, P Baringer, A Bean, D Besson, D Coppage, R Davis, S Kotov, I Kravchenko, N Kwak, L Zhou, S Anderson, Y Kubota, SJ Lee, R Mahapatra, JJ O'Neill, R Poling, T Riehle, A Smith, MS Alam, SB Athar, Z Ling, AH Mahmood, S Timm, F Wappler, A Anastassov, JE Duboscq, KK Gan, C Gwon, T Hart, K Honscheid, H Kagan, R Kass, J Lee, J Lorenc, H Schwarthoff, A Wolf, MM Zoeller, SJ Richichi, H Severini, P Skubic, A Undrus, M Bishai, S Chen, J Fast, JW Hinson, N Menon, DH Miller, EI Shibata, IPJ Shipsey, S Glenn, Y Kwon, AL Lyon, EH Thorndike, CP Jessop, K Lingel, H Marsiske, ML Perl, V Savinov, D Ugolini, X Zhou, TE Coan, V Fadeyev, I Korolkov, Y Maravin, I Narsky, R Stroynowski, J Ye, T Wlodek, M Artuso, S Ayad, E Dambasuren, S Kopp, G Majumder, GC Moneti, R Mountain, S Schuh, T Skwarnicki, S Stone, A Titov, G Viehhauser, JC Wang, SE Csorna, KW McLean, S Marka, Z Xu, R Godang, K Kinoshita, IC Lai, P Pomianowski, S Schrenk
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A precise measurement of the partial decay width ratio Rb0 = Γbb̄/Γhad

European Physical Journal C 10:3 (1999) 415-442

Authors:

P Abreu, W Adam, T Adye, P Adzic, Z Albrecht, T Alderweireld, GD Alekseev, R Alemany, T Allmendinger, PP Allport, S Almehed, U Amaldi, S Amato, EG Anassontzis, P Andersson, A Andreazza, S Andringa, P Antilogus, WD Apel, Y Arnoud, B Åsman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, G Barbiellini, R Barbier, DY Bardin, G Barker, A Baroncelli, M Battaglia, M Baubillier, KH Becks, M Begalli, P Beilliere, Y Belokopytov, K Belous, AC Benvenuti, C Berat, M Berggren, D Bertini, D Bertrand, M Besancon, F Bianchi, M Bigi, MS Bilenky, MA Bizouard, D Bloch, HM Blom, M Bonesini, W Bonivento, M Boonekamp, PSL Booth, AW Borgland, G Borisov, C Bosio, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, I Boyko, I Bozovic, M Bozzo, P Branchini, T Brenke, RA Brenner, P Bruckman, JM Brunet, L Bugge, T Buran, T Burgsmueller, P Buschmann, S Cabrera, M Caccia, M Calvi, T Camporesi, V Canale, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, V Chabaud, M Chapkin, P Charpentier, L Chaussard, P Checchia, GA Chelkov, R Chierici, P Chliapnikov, P Chochula, V Chorowicz, J Chudoba, K Cieslik, P Collins, R Contri, E Cortina

Abstract:

The partial decay width of the Z to bb̄ quark pairs has been measured by the DELPHI detector at LEP using data taken in the years 1992 to 1995. Decays of b-hadrons were tagged by several methods using tracks with large impact parameters and/or reconstructed secondary vertices, complemented by event shape variables. Combining these methods in a multivariate analysis the value Γ(Z → bb̄)/Γ(Z → had) = 0.21634 ± 0.00067 (stat) ± 0.00060 (syst) was obtained, where the cc̄ production fraction was fixed to its Standard Model value.
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A search for invisible Higgs bosons produced in e+e- interactions at LEP 2 energies

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 459:1-3 (1999) 367-381

Authors:

P Abreu, W Adam, T Adye, P Adzic, Z Albrecht, T Alderweireld, GD Alekseev, R Alemany, T Allmendinger, PP Allport, S Almehed, U Amaldi, N Amapane, S Amato, EG Anassontzis, P Andersson, A Andreazza, S Andringa, P Antilogus, WD Apel, Y Arnoud, B Åsman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, G Barbiellini, R Barbier, DY Bardin, G Barker, A Baroncelli, M Battaglia, M Baubillier, KH Becks, M Begalli, A Behrmann, P Beilliere, Y Belokopytov, K Belous, NC Benekos, AC Benvenuti, C Berat, M Berggren, D Bertini, D Bertrand, M Besancon, M Bigi, MS Bilenky, MA Bizouard, D Bloch, HM Blom, M Bonesini, W Bonivento, M Boonekamp, PSL Booth, AW Borgland, G Borisov, C Bosio, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, I Boyko, I Bozovic, M Bozzo, P Branchini, T Brenke, RA Brenner, P Bruckman, JM Brunet, L Bugge, T Buran, T Burgsmueller, B Buschbeck, P Buschmann, S Cabrera, M Caccia, M Calvi, T Camporesi, V Canale, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, V Chabaud, M Chapkin, P Charpentier, L Chaussard, P Checchia, GA Chelkov, R Chierici, P Chliapnikov, P Chochula, V Chorowicz, J Chudoba, K Cieslik

Abstract:

Searches for HZ production with the Higgs boson decaying into an invisible final state have been performed with the data collected by the DELPHI experiment up to the centre-of-mass energy of 183 GeV. The hadronic and muon pair final states of the Z boson were analysed. From the absence of signal, upper limits on the cross-section and the corresponding Higgs boson mass limits were set at 95% confidence level. The results are interpreted as excluded parameter regions in the framework of the minimal supersymmetric standard model and in the simplest Majoron model with one Higgs doublet and one Higgs singlet field. © 1999 Elsevier Science B.V. All rights reserved.
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Energy dependence of event shapes and of αs at LEP 2

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 456:2-4 (1999) 322-340

Authors:

P Abreu, W Adam, T Adye, P Adzic, Z Albrecht, T Alderweireld, GD Alekseev, R Alemany, T Allmendinger, PP Allport, S Almehed, U Amaldi, N Amapane, S Amato, EG Anassontzis, P Andersson, A Andreazza, S Andringa, P Antilogus, WD Apel, Y Arnoud, B Asman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, G Barbiellini, R Barbier, DY Bardin, G Barker, A Baroncelli, M Battaglia, M Baubillier, KH Becks, M Begalli, A Behrmann, P Beilliere, Y Belokopytov, K Belous, NC Benekos, AC Benvenuti, C Berat, M Berggren, D Bertini, D Bertrand, M Besancon, F Bianchi, M Bigi, MS Bilenky, MA Bizouard, D Bloch, HM Blom, M Bonesini, W Bonivento, M Boonekamp, PSL Booth, AW Borgland, G Borisov, C Bosio, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, I Boyko, I Bozovic, M Bozzo, P Branchini, T Brenke, RA Brenner, P Bruckman, JM Brunet, L Bugge, T Buran, T Burgsmueller, B Buschbeck, P Buschmann, S Cabrera, M Caccia, M Calvi, T Camporesi, V Canale, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, V Chabaud, M Chapkin, P Charpentier, L Chaussard, P Checchia, GA Chelkov, R Chierici, P Chliapnikov, P Chochula, V Chorowicz, J Chudoba

Abstract:

Infrared and collinear safe event shape distributions and their mean values are determined using the data taken at five different centre of mass energies above MZ with the DELPHI detector at LEP. From the event shapes, the strong coupling αS is extracted in θ(αS2), NLLA and a combined scheme using hadronisation corrections evaluated with fragmentation model generators as well as using an analytical power ansatz. Comparing these measurements to those obtained at MZ, the energy dependence (running) of αS is accessible. The logarithmic energy slope of the inverse strong coupling is measured to be d αS-1/d log (Ecm) = 1.39 + 0.34(stat) + 0.17(syst), in good agreement with the QCD expectation of 1.27. © 1999 Published by Elsevier Science B.V. All rights reserved.
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