Accelerator Neutrinos

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Evaluation of the LEP centre-of-mass energy above the W-pair production threshold

European Physical Journal C 11:4 (1999) 573-585

Authors:

A Blondel, M Bœge, E Bravin, P Bright-Thomas, T Camporesi, B Dehning, M Heemskerk, M Hildreth, M Koratzinos, E Lançon, G Mugnai, A Müller, E Peschardt, M Placidi, N Qi, G Quast, P Renton, F Sonnemann, E Torrence, A Weber, PS Wells, J Wenninger, G Wilkinson

Abstract:

Knowledge of the centre-of-mass energy at LEP2 is of primary importance to set the absolute energy scale for the measurement of the W-boson mass. The beam energy above 80 GeV is derived from continuous measurements of the magnetic bending field by 16 NMR probes situated in a number of the LEP dipoles. The relationship between the fields measured by the probes and the beam energy is calibrated against precise measurements of the average beam energy between 41 and 55GeV made using the resonant depolarisation technique. The linearity of the relationship is tested by comparing the fields measured by the probes with the total bending field measured by a flux loop. This test results in the largest contribution to the systematic uncertainty. Several further corrections are applied to derive the centre-of-mass energies at each interaction point. In addition, the centre-of-mass energy spread is evaluated. The beam energy has been determined with a precision of 25 MeV for the data taken in 1997, corresponding to a relative precision of 2.7 × 10-4. This is small in comparison to the present uncertainty on the W mass measurement at LEP. However, the ultimate statistical precision on the W mass with the full LEP2 data sample should be around 25 MeV, and a smaller uncertainty on the beam energy is desirable. Prospects for improvements are outlined.
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Evidence of color coherence effects in W + jets events from pp collisions at √s = 1.8 TeV

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 464:1-2 (1999) 145-155

Authors:

B Abbott, M Abolins, V Abramov, BS Acharya, I Adam, DL Adams, M Adams, S Ahn, V Akimov, GA Alves, N Amos, EW Anderson, 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, G Blazey, S Blessing, P Bloom, A Boehnlein, NI Bojko, F Borcherding, C Boswell, A Brandt, R Breedon, G Briskin, R Brock, A Bross, D Buchholz, VS Burtovoi, JM Butler, W Carvalho, D Casey, Z Casilum, H Castilla-Valdez, D Chakraborty, KM Chan, SV Chekulaev, W Chen, DK Cho, S Choi, S Chopra, BC Choudhary, JH Christenson, M Chung, D Claes, AR Clark, WG Cobau, J Cochran, L Coney, WE Cooper, D Coppage, 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, J Estrada, H Evans, VN Evdokimov, T Fahland, MK Fatyga, S Feher, D Fein, T Ferbel

Abstract:

We report the results of a study of color coherence effects in pp collisions based on data collected by the DØ detector during the 1994-1995 run of the Fermilab Tevatron Collider, at a center of mass energy √s = 1.8 TeV. Initial-to-final state color interference effects are observed by examining particle distribution patterns in events with a W boson and at least one jet. The data are compared to Monte Carlo simulations with different color coherence implementations and to an analytic modified-leading-logarithm perturbative calculation based on the local parton-hadron duality hypothesis. © 1999 Published by Elsevier Science B.V. All rights reserved.
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Inclusive jet cross section in p̄p collisions at √ = 1.8 TeV

Physical Review Letters 82:12 (1999) 2451-2456

Authors:

B Abbott, M Abolins, V Abramov, BS Acharya, I Adam, DL Adams, M Adams, S Ahn, H Aihara, H Alves, N Amos, EW Anderson, R Astur, MM Baarmand, VV Babintsev, L Babukhadia, A Baden, V Balamurali, 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, LP Chen, 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

Abstract:

We have made a precise measurement of the central inclusive jet cross section at √s = 1.8 TeV. The measurement is based on an integrated luminosity of 92pb-1 collected at the Fermilab Tevatron p̄p Collider with the D0 detector. The cross section, reported as a function of jet transverse energy (ET ≥ 60 GeV) in the pseudorapidity interval |±| ≤ 0.5, is in good agreement with predictions from next-to-leading order quantum chromodynamics. © 1999 The American Physical Society.
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Measurement of the decay rate and form factor parameter αK* in the decay KL → e+e-γ

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 458:4 (1999) 553-563

Authors:

V Fanti, A Lai, L Musa, D Marras, A Nappi, B Hay, RW Moore, KN Moore, DJ Munday, MD Needham, MA Parker, TO White, SA Wotton, G Barr, G Bocquet, J Bremer, A Ceccucci, D Cundy, N Doble, W Funk, L Gatignon, A Gianoli, A Gonidec, G Govi, P Grafström, W Kubischta, A Lacourt, S Luitz, G Kesseler, JP Matheys, A Norton, S Palestini, B Panzer-Steindel, D Schinzel, H Taureg, M Velasco, O Vossnack, H Wahl, G Wirrer, V Kekelidze, A Mestvirishvili, G Tatishvili, I Potrebenikov, A Tkatchev, A Zinchenko, O Boyle, VJ Martin, IG Knowles, HLC Parsons, P Dalpiaz, J Duclos, PL Frabetti, M Martini, F Petrucci, M Porcu, M Savrié, A Bizzeti, M Calvetti, G Collazuol, G Graziani, E Iacopini, M Lenti, A Michetti, HG Becker, H Blümer, P Buchholz, D Coward, C Ebersberger, H Fox, A Kalter, K Kleinknecht, U Koch, L Köpke, B Renk, J Scheidt, J Schmidt, V Schönharting, Y Schué, R Wilhelm, A Winhart, M Wittgen, JC Chollet, S Crépé, L Iconomidou-Fayard, L Fayard, J Ocariz, G Unal, D Vattolo, I Wingerter, G Anzivino, P Cenci, P Lubrano, M Pepe, B Gorini, P Calafiura, R Carosi, C Cerri, M Cirilli, F Costantini, R Fantechi

Abstract:

The decay rate of the neutral K meson KL → e+e-γ has been measured with the NA48 detector at the CERN SPS. A total of 6864 events has been observed with an estimated background of 10 events. The branching ratio is Γ(KL → e+e-γ)/Γ(KL → all) = (1.06 ± 0.02stat ± 0.02sys ± 0.04calc) × 10-5 The parameter αK* describing the relative strength of the two contributing amplitudes to this decay through intermediate pseudoscalar or vector mesons was measured to be αK* = -0.36 ± 0.06stat ± 0.02sys. © 1999 Published by Elsevier Science B.V. All rights reserved.
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Measurement of the high-mass drell-yan cross section and limits on quark-electron compositeness scales

Physical Review Letters 82:24 (1999) 4769-4774

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, 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, E Flattum

Abstract:

We present a measurement of the Drell-Yan cross section at high dielectron invariant mass using 120 pb-1 of data collected in pp collisions at √ s = 1.8 TeV by the D0 Collaboration during 1992-1996. No deviation from standard model expectations is observed. We use the data to set limits on the quark-electron compositeness scale. The 95% confidence level lower limits on the compositeness scale vary between 3.3 and 6.1 TeV depending on the assumed form of the effective contact interaction. © 1999 The American Physical Society.
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