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THE PERFORMANCE OF THE ZEUS CENTRAL TRACKING DETECTOR Z-BY-TIMING ELECTRONICS IN A TRANSPUTER-BASED DATA-ACQUISITION SYSTEM

NUCL PHYS B (1993) 181-188

Authors:

B FOSTER, GP HEATH, TJ LLEWELLYN, DM GINGRICH, N HARNEW, PM HALLAMBAKER, T KHATRI, IC MCARTHUR, P MORAWITZ, J NASH, PD SHIELD, S TOPPJORGENSEN, FF WILSON, DB ALLEN, RC CARTER, MD JEFFS, MC MORRISSEY, SPH QUINTON, JB LANE, M POSTRANECKY

Initial study of deep inelastic scattering with ZEUS at HERA

Physics Letters B 303:1-2 (1993) 183-197

Authors:

M Derrick, D Krakauer, S Magill, B Musgrave, J Repond, S Repond, R Stanek, RL Talaga, J Thron, F Arzarello, R Ayad, G Barbagli, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, P Bruni, G Cara Romeo, G Castellini, M Chiarini, L Cifarelli, F Cindolo, F Ciralli, A Contin, S D'Auria, C Del Papa, F Frasconi, P Giusti, G Iacobucci, G Laurenti, G Levi, Q Lin, B Lisowski, G Maccarrone, A Margotti, T Massam, R Nania, C Nemoz, F Palmonari, G Sartorelli, R Timellini, Y Zamora Garcia, A Zichichi, A Bargende, J Crittenden, H Dabbous, K Desch, B Diekmann, T Doeker, M Geerts, G Geitz, B Gutjahr, H Hartmann, J Hartmann, D Haun, K Heinloth, E Hilger, HP Jakob, S Kramarczyk, M K眉ckes, A Mass, S Mengel, J Mollen, D Monaldi, H M眉sch, E Paul, R Schattevoy, JL Schneider, R Wedemeyer, A Cassidy, DG Cussans, N Dyce, HF Fawcett, B Foster, R Gilmore, GP Heath, M Lancaster, TJ Llewellyn, J Malos, CJS Morgado, RJ Tapper, SS Wilson, RR Rau, T Barillari, M Schioppa, G Susinno, A Bernstein, A Caldwell, I Gialas, JA Parsons, S Ritz, F Sciulli, PB Straub, L Wai, S Yang, W Burkot, A Eskreys, K Piotrzkowski

Abstract:

Results are presented on neutral current, deep inelastic scattering measured in collisions of 26.7 GeV electrons and 820 GeV protons. The events typically populate a range in Q2 from 10 to 100 GeV2. The values of x extend down to x 鈭 10-4 which is two orders of magnitude lower than previously measured at such Q2 values in fixed target experiments. The measured cross sections are in accord with the extrapolations of current parametrisations of parton distributions. 漏 1993.

Determination of 伪s using the next-to-leading-log approximation of QCD

Zeitschrift f眉r Physik C: Particles and Fields 59:1 (1993) 21-33

Authors:

P Abreu, W Adam, T Adye, E Agasi, R Aleksan, GD Alekseev, A Algeri, P Allen, A Almehed, SJ Alvsvaag, U Amaldi, A Andreazza, P Antilogus, WD Apel, RJ Apsimon, Y Arnoud, B 脜sman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, R Barate, G Barbiellini, DY Bardin, GJ Barker, A Baroncelli, O Barring, JA Barrio, W Bartl, MJ Bates, M Battaglia, M Baubillier, KH Becks, CJ Beeston, M Begalli, P Beilliere, Y Belokopyptov, P Beltran, D Benedic, AC Benvenuti, M Berggren, D Bertrand, F Bianchi, MS Bilenky, P Billoir, J Bjarne, D Bloch, S Blyth, V Bocci, PN Bogolubov, T Bolognese, M Bonesini, W Bonivento, PSL Booth, G Borisov, H Borner, C Bosio, B Bostjancic, S Bosworth, O Botner, B Bouquet, C Bourdarios, TJV Bowcock, M Bozzo, S Braibant, P Branchini, KD Brand, RA Brenner, H Briand, C Bricman, RCA Brown, N Brummer, JM Brunet, L Bugge, T Buran, H Burmeister, JAMA Buytaert, M Caccia, M Calvi, AJ Camacho Rozas, R Campion, T Camporesi, V Canale, F Cao, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, L Cerrito, V Chabaud, A Chan, M Chapkin, P Charpentier, L Chaussard, J Chauveau, P Checchia, GA Chelkov

Abstract:

A new measurement of 伪s is obtained from the distributions in thrust, heavy jet mass, energy-energy correlation and two recently introduced jet broadening variables following a method proposed by Catani, Trentadue, Turnock and Webber. This method includes the full calculation of O(s2) terms and leading and next-to-leading logarithms resummed to all orders of 伪s. The analysis is based on data taken with the DELPHI detector at LEP during 1991. I its found that the inclusion of the resummed leading and next-to-leading logarithms reduces the scale dependence of 伪s and allows an extension of the fit range towards the infrared limit of the kinematical range. The combined value for 伪s obtained at the scale 渭2=MZ2 is: {Mathematical expression} 漏 1993 Springer-Verlag.

A search for lepton flavour violation in Z0 decays

Physics Letters B 298:1-2 (1993) 247-256

Authors:

P Abreu, W Adam, T Adye, E Agasi, GD Alekseev, A Algeri, P Allen, S Almehed, SJ Alvsvaag, U Amaldi, EG Anassontzis, A Andreazza, P Antilogus, WD Apel, RJ Apsimon, B 脜sman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, R Barate, G Barbiellini, DY Bardin, G Barker, A Baroncelli, O Barring, JA Barrio, W Bartl, MJ Bates, M Battaglia, M Baubillier, KH Becks, CJ Beeston, M Begalli, P Beilliere, Y Belokopytov, P Beltran, D Benedic, AC Benvenuti, M Berggren, D Bertrand, F Bianchi, MS Bilenky, P Billoir, J Bjarne, D Bloch, S Blyth, V Bocci, PN Bogolubov, T Bolognese, M Bonesini, W Bonivento, PSL Booth, P Borgeaud, G Borisov, H Borner, C Bosio, B Bostjancic, S Bosworth, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, M Bozzo, S Braibantc, P Branchini, KD Brand, RA Brenner, H Briand, C Bricman, RCA Brown, N Brummer, JM Brunet, L Bugge, T Buran, H Burmeister, JAMA Buytaert, M Caccia, M Calvi, AJ Camacho Rozas, R Campion, T Camporesi, V Canale, F Cao, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, L Cerrito, V Chabaud, A Chan, P Charpentier, L Chaussard, J Chauveau, P Checchia, GA Chelkov

Abstract:

A search for lepton flavour violation through the decays Z0 鈫 e渭, e蟿 and 渭蟿 was made with the DELPHI detector at LEP, using a sample corresponding to an integrated luminosity of 11.2 pb-1. The number of candidates was consistent with the estimated background. The upper limit on the branching ratio (at 95% confidence level) for Z0 鈫 e渭 was 3.2 脳 10-5, for Z0 鈫 e蟿 was 10.8 脳 10-5 and for Z0 鈫 渭蟿 was 13.5 脳 10-5. 漏 1993.

Measurement of inclusive production of light meson resonances in hadronic decays of the Z0

Physics Letters B 298:1-2 (1993) 236-246

Authors:

P Abreu, W Adam, T Adye, E Agasi, GD Alekseev, A Algeri, P Allen, S Almehed, SJ Alvsvaag, U Amaldi, EG Anassontzis, A Andreazza, P Antilogus, WD Apel, RJ Apsimon, B 脜sman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, R Barate, G Barbiellini, DY Bardin, G Barker, A Baroncelli, O Barring, JA Barrio, W Bartl, MJ Bates, M Battaglia, M Baubillier, KH Becks, CJ Beeston, M Begalli, P Beilliere, Y Belokopytov, P Beltran, D Benedic, AC Benvenuti, M Berggren, D Bertrand, F Bianchi, MS Bilenky, P Billior, J Bjarne, D Bloch, S Blyth, V Bocci, PN Bogolubov, T Bolognese, M Bonesini, W Bonivento, PSL Booth, P Borgeaud, G Borisov, H Borner, C Bosio, B Bostjancic, S Bosworth, O Botner, B Bouquet, C Bourdarion, TJV Bowcock, M Bozzo, S Braibant, P Branchini, KD Brand, RA Brenner, H Briand, C Bricman, RCA Brown, N Brummer, JM Brunet, L Bugge, T Buran, H Burmeister, JAMA Buytaert, M Caccia, M Calvi, AJ Camacho Rozas, R Campion, T Camporesi, V Canale, F Cao, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, L Cerrito, V Chabaud, A Chan, M Chapkin, L Chaussard, J Chauveau, P Checchia, GA Chelkov, L Chevalier

Abstract:

A study of inclusive production of the meson resonances 蟻0, K*0 (892), f{hook}0 (975) and f{hook}2 (1270) in hadronic decays of the Z0 is presented. The measured mean meson multiplicity per hadronic event is 0.83 卤 0.14 for the 蟻0 0.64 卤 0.24 for the K*0 (892), 0.10 卤 0.04 for the f{hook}0 (975) in the momentum range p > 0.05pbeam (xp > 0.05) and 0.11 卤 0.05 for the f{hook}2 (1270) for xp > 0.1. These values and the corresponding differential cross sections ( 1 蟽hadr) d蟽 dxp for the vector mesons are in good agreement with the predictions of the JETSET 7.3 PS and HERWIG 5.4 models. The f{hook}2 (1270) production is overestimated by HERWIG but its xp-shape is correctly reproduced. The measured ratios of the production cross sections 蟽(f{hook}2(1270)) 蟽(蟻0) = 0.22 卤 0.08 and 蟽(f{hook}2(1270)) 蟽(f{hook}0(975)) = 3-1+7 for xp > 0.1 are consistent with the results obtained in hadronic reactions. 漏 1993.