Accelerator Neutrinos

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Dijet production by color-singlet exchange at the fermilab tevatron

Physical Review Letters 80:6 (1998) 1156-1161

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, T Arisawa, T Asakawa, W Ashmanskas, M Atac, F Azfar, P Azzi-Bacchetta, N Bacchetta, W Badgett, S Bagdasarov, MW Bailey, J Bao, P De Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, E Barzi, B Barzi, G Bauer, T Baumann, F Bedeschi, S Behrends, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Benlloch, J Bensinger, D Benton, A Beretvas, JP Berge, J Berryhill, S Bertolucci, S Bettelli, B Bevensee, A Bhatti, K Biery, M Binkley, D Bisello, RE Blair, C Blocker, S Blusk, A Bodek, W Bokhari, G Bolla, V Bolognesi, Y Bonushkin, D Bortoletto, J Boudreau, L Breccia, C Bromberg, N Bruner, E Buckley-Geer, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, C Campagnari, M Campbell, A Caner, W Carithers, D Carlsmith, J Cassada, A Castro, D Cauz, Y Cen, A Cerri, F Cervelli, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, M Chertok, G Chiarelli, T Chikamatsu, CN Chiou, L Christofek, S Cihangir, AG Clark, M Cobal, E Cocca, M Contreras, J Conway, J Cooper, M Cordelli, C Couyoumtzelis, D Crane, D Cronin-Hennessy, R Culbertson, T Daniels

Abstract:

We report a new measurement of dijet production by color-singlet exchange in pp® collisions at √s = 1.8 TeV at the Fermilab Tevatron. In a sample of events with two jets of transverse energy EjetT > 20 GeV, pseudorapidity in the range 1.8 < |ηjet| < 3.5, and η1η2 < 0, we find that a fraction R = [1.13 ± 0.12(stat) ± 0.11(syst)]% has a pseudorapidity gap within |η| < 1 between the jets that can be attributed to color-singlet exchnage. The fraction R shows no significant dependence on EjetT or on the pseudorapidity separation between the jets. © 1998 American Physical Society.
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Direct measurement of the top quark mass by the DØ Collaboration

Physical Review D - Particles, Fields, Gravitation and Cosmology 58:5 (1998)

Authors:

B Abbott, M Abolins, BS Acharya, I Adam, DL Adams, M Adams, S Ahn, H Aihara, GA Alves, N Amos, EW Anderson, R Astur, MM Baarmand, A Baden, V Balamurali, J Balderston, B Baldin, S Banerjee, J Bantly, E Barberis, JF Bartlett, K Bazizi, 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 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, 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, GE Forden

Abstract:

We determine the top quark mass [Formula Presented] using [Formula Presented] pairs produced in the DØ detector by [Formula Presented] [Formula Presented] collisions in a [Formula Presented] exposure at the Fermilab Tevatron. We make a two constraint fit to [Formula Presented] in [Formula Presented] final states with one W boson decaying to [Formula Presented] and the other to [Formula Presented] or [Formula Presented] Likelihood fits to the data yield [Formula Presented] When this result is combined with an analysis of events in which both W bosons decay into leptons, we obtain [Formula Presented] An alternate analysis, using three constraint fits to fixed top quark masses, gives [Formula Presented] consistent with the above result. Studies of kinematic distributions of the top quark candidates are also presented. 14.65.Ha, 13.85.Ni, 13.85.Qk. © 1998 The American Physical Society.
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First search for CP violation in tau lepton decay

Physical Review Letters 81:18 (1998) 3823-3827

Authors:

S Anderson, Y Kubota, SJ Lee, 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, D Fujino, KK Gan, T Hart, K Honscheid, H Kagan, R Kass, J Lee, H Schwarthoff, MB Spencer, M Sung, A Undrus, A Wolf, MM Zoeller, SJ Richichi, H Severini, P Skubic, M Bishai, J Fast, JW Hinson, N Menson, DH Miller, EI Shibata, IPJ Shipsey, M Yurko, S Glenn, Y Kwon, AL Lyon, S Roberts, 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, V Shelkov, J Staeck, R Stroynowski, I Volobouev, J Ye, M Artuso, F Azfar, A Efimov, M Goldberg, D He, S Kopp, GC Moneti, R Mountain, S Schuh, T Skwarnicki, S Stone, G Viehhauser, JC Wang, X Xing, J Bartelt, SE Csorna, V Jain, KW McLean, S Marka, R Godang, K Kinoshita, IC Lai, P Pomianowski, S Schrenk, G Bonvicini, D Cinabro, R Greene, LP Perera, GJ Zhou, M Chadha, S Chan, G Eigen, JS Miller, M Schmidtler, J Urheim, AJ Weinstein, F Würthwein, DW Bliss, DE Jaffe

Abstract:

We have performed the first search for CP violation in tau lepton decay. CP violation in lepton decay does not occur in the minimal standard model but can occur in extensions such as the multi-Higgs doublet model. It appears as a characteristic difference between the τ− and τ+ decay angular distributions for the semileptonic decay modes such as τ− → K0 π− ν. We define an observable asymmetry to exploit this and find no evidence for any CP violation. © 1998 The American Physical Society.
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Flavor-specific inclusive B decays to charm

Physical Review Letters 80:6 (1998) 1150-1155

Authors:

TE Coan, V Fadeyev, I Korolkov, Y Maravin, I Narsky, V Shelkov, J Staeck, R Stroynowski, I Volobouev, J Ye, M Artuso, F Azfar, A Efimov, M Goldberg, D He, S Kopp, GC Moneti, R Mountain, S Schuh, T Skwarnicki, S Stone, G Viehhauser, X Xing, J Bartelt, SE Csorna, V Jain, KW McLean, S Marka, R Godang, K Kinoshita, IC Lai, P Pomianowski, S Schrenk, G Bonvicini, D Cinabro, R Greene, LP Perera, GJ Zhou, B Barish, M Chadha, S Chan, G Eigen, JS Miller, C O’grady, M Schmidtler, J Urheim, AJ Weinstein, F Würthwein, DW Bliss, G Masek, HP Paar, S Prell, V Sharma, DM Asner, J Gronberg, TS Hill, DJ Lange, RJ Morrison, HN Nelson, TK Nelson, JD Richman, D Roberts, A Ryd, MS Witherell, R Balest, BH Behrens, WT Ford, A Gritsan, H Park, J Roy, JG Smith, JP Alexander, C Bebek, BE Berger, K Berkelman, K Bloom, V Boisvert, DG Cassel, HA Cho, DS Crowcroft, M Dickson, S von Dombrowski, PS Drell, KM Ecklund, R Ehrlich, AD Foland, P Gaidarev, L Gibbons, B Gittelman, SW Gray, DL Hartill, BK Heltsley, PI Hopman, J Kandaswamy, PC Kim, DL Kreinick, T Lee, Y Liu, NB Mistry, CR Ng

Abstract:

We have measured the branching fractions for B → D®X, B → D®X, and B → D®Xℓ+v. From these results and some previously measured branching fractions, we obtain B(b → cc®s) = (21.9 ± 3.7)%, B(b → sg) < 6.8% at 90% C.L., and B(D0 → K− π+ = (3.69 ± 0.20)%. Implications for the “B semileptonic decay problem” (measured branching fraction being below theoretical expectations) are discussed. With the increase in the value of B(b → cc®s) due to B → DX, the discrepancy is no longer statistically compelling. © 1998 American Physical Society.
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Jet pseudorapidity distribution in direct photon events in pp collisions at vs=1.8TeV

Physical Review D Particles Fields Gravitation and Cosmology 57:3 (1998) 1359-1365

Authors:

F Abe, MG Albrow, SR Amendolia, D Amidei, J Antos, C Anway-Wiese, G Apollinari, H Areti, M Atac, P Auchincloss, F Azfar, P Azzi, N Bacchetta, W Badgett, MW Bailey, J Bao, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, P Bartalini, G Bauer, T Baumann, F Bedeschi, S Behrends, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Benlloch, J Bensinger, D Benton, A Beretvas, JP Berge, S Bertolucci, A Bhatti, K Biery, M Binkley, F Bird, D Bisello, RE Blair, C Blocker, A Bodek, W Bokhari, V Bolognesi, D Bortoletto, C Boswell, T Boulos, G Brandenburg, C Bromberg, E Buckley-Geer, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, J Cammerata, C Campagnari, M Campbell, A Caner, W Carithers, D Carlsmith, A Castro, Y Cen, F Cervelli, HY Chao, J Chapman, MT Cheng, G Chiarelli, T Chikamatsu, CN Chiou, L Christofek, S Cihangir, AG Clark, M Cobal, M Contreras, J Conway, J Cooper, M Cordelli, C Couyoumtzelis, D Crane, JD Cunningham, T Daniels, F DeJongh, S Delchamps, S Dell’Agnello, M Dell’Orso, L Demortier, B Denby, M Deninno, PF Derwent, T Devlin, M Dickson, JR Dittmann, S Donati, RB Drucker, A Dunn, K Einsweiler, JE Elias, R Ely

Abstract:

We present the first measurement of the jet pseudorapidity distribution in direct photon events from a sample of (Formula presented) collisions at (Formula presented) recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily from hard quark-gluon Compton scattering, (Formula presented) with the final state quark producing the jet of hadrons. The jet pseudorapidity distribution in this model is sensitive to parton momentum fractions between 0.015 and 0.15. We find that the shape of the measured pseudorapidity distribution agrees well with next-to-leading order QCD calculations. © 1998 The American Physical Society.
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