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Second generation leptoquark search in pp̄ collisions at s=1.8 TeV

Physical Review Letters 75:20 (1995) 3618-3623

Authors:

S Abachi, B Abbott, M Abolins, BS Acharya, I Adam, DL Adams, M Adams, S Ahn, H Aihara, J Alitti, G Alvarez, GA Alves, E Amidi, N Amos, EW Anderson, SH Aronson, R Astur, RE Avery, A Baden, V Balamurali, J Balderston, B Baldin, J Bantly, JF Bartlett, K Bazizi, J Bendich, SB Beri, I Bertram, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, A Bischoff, N Biswas, G Blazey, S Blessing, P Bloom, A Boehnlein, NI Bojko, F Borcherding, J Borders, C Boswell, A Brandt, R Brock, A Bross, D Buchholz, VS Burtovoi, JM Butler, D Casey, H Castilla-Valdez, D Chakraborty, SM Chang, SV Chekulaev, LP Chen, W Chen, L Chevalier, S Chopra, BC Choudhary, JH Christenson, M Chung, D Claes, AR Clark, WG Cobau, J Cochran, WE Cooper, C Cretsinger, D Cullen-Vidal, MAC Cummings, D Cutts, OI Dahl, K De, M Demarteau, R Demina, K Denisenko, D Denisov, SP Denisov, W Dharmaratna, HT Diehl, M Diesburg, G Di Loreto, R Dixon, P Draper, J Drinkard, Y Ducros, SR Dugad, S Durston-Johnson, D Edmunds, J Ellison, VD Elvira, R Engelmann, S Eno, G Eppley, P Ermolov, OV Eroshin, VN Evdokimov, S Fahey, T Fahland, M Fatyga, MK Fatyga, J Featherly

Abstract:

We report on a search for second generation scalar leptoquarks with the DO detector at the Fermilab Tevatron pp̄ collider at s=1.8 TeV. This search is based on 12.7 pb-1 of data. Second generation leptoquarks are assumed to be produced in pairs and to decay into a muon and quark with branching ratio β or into a neutrino and quark with branching ratio 1-β. We obtain cross section times branching ratio limits as a function of leptoquark mass and set lower limits on the leptoquark mass at the 95% confidence level. © 1995 The American Physical Society.

Study of the strong coupling constant using W+Jet processes

Physical Review Letters 75:18 (1995) 3226-3231

Authors:

S Abachi, B Abbott, M Abolins, BS Acharya, I Adam, DL Adams, M Adams, S Ahn, H Aihara, J Alitti, G Lvarez, GA Alves, E Amidi, N Amos, EW Anderson, SH Aronson, R Astur, RE Avery, A Baden, V Balamurali, J Balderston, B Baldin, J Bantly, JF Bartlett, K Bazizi, J Bendich, SB Beri, I Bertram, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, A Bischoff, N Biswas, G Blazey, S Blessing, P Bloom, A Boehnlein, NI Bojko, F Borcherding, J Borders, C Boswell, A Brandt, R Brock, A Bross, D Buchholz, VS Burtovoi, JM Butler, W Carvalho, D Casey, H Castilla-Valdez, D Chakraborty, SM Chang, SV Chekulaev, LP Chen, W Chen, L Chevalier, S Chopra, BC Choudhary, JH Christenson, M Chung, D Claes, AR Clark, WG Cobau, J Cochran, WE Cooper, C Cretsinger, D Cullen-Vidal, MAC Cummings, D Cutts, OI Dahl, K De, M Demarteau, R Demina, K Denisenko, N Denisenko, D Denisov, SP Denisov, W Dharmaratna, HT Diehl, M Diesburg, G Di Loreto, R Dixon, P Draper, J Drinkard, Y Ducros, SR Dugad, S Durston-Johnson, D Edmunds, J Ellison, VD Elvira, R Engelmann, S Eno, G Eppley, P Ermolov, OV Eroshin, VN Evdokimov, S Fahey, T Fahland, M Fatyga

Abstract:

The ratio of the number of W+1 jet to W+0 jet events is measured with the D0 detector using data from the 1992-93 Tevatron Collider run. For the W→eν channel with a minimum jet ET cutoff of 25 GeV, the experimental ratio is 0.065±0.003stat±0.007syst. Next-to-leading order QCD predictions for various parton distributions agree well with each other and are all over 1 standard deviation below the measurement. Varying the strong coupling constant αs in both the parton distributions and the partonic cross sections simultaneously does not remove this discrepancy. © 1995 The American Physical Society.

Top quark search with the D0 1992-1993 data sample

Physical Review D 52:9 (1995) 4877-4919

Authors:

S Abachi, B Abbott, M Abolins, BS Acharya, I Adam, DL Adams, M Adams, S Ahn, H Aihara, J Alitti, G Álvarez, GA Alves, E Amidi, N Amos, EW Anderson, SH Aronson, R Astur, RE Avery, A Baden, V Balamurali, J Balderston, B Baldin, J Bantly, JF Bartlett, K Bazizi, J Bendich, SB Beri, I Bertram, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, A Bischoff, N Biswas, G Blazey, S Blessing, P Bloom, A Boehnlein, NI Bojko, F Borcherding, J Borders, C Boswell, A Brandt, R Brock, A Bross, D Buchholz, VS Burtovoi, JM Butler, D Casey, H Castilla-Valdez, D Chakraborty, SM Chang, SV Chekulaev, LP Chen, W Chen, L Chevalier, S Chopra, BC Choudhary, JH Christenson, M Chung, D Claes, AR Clark, WG Cobau, J Cochran, WE Cooper, C Cretsinger, D Cullen-Vidal, MAC Cummings, D Cutts, OI Dahl, K De, M Demarteau, R Demina, K Denisenko, N Denisenko, D Denisov, SP Denisov, W Dharmaratna, HT Diehl, M Diesburg, G Di Loreto, R Dixon, P Draper, J Drinkard, Y Ducros, SR Dugad, S Durston-Johnson, D Edmunds, J Ellison, VD Elvira, R Engelmann, S Eno, G Eppley, P Ermolov, OV Eroshin, VN Evdokimov, S Fahey, T Fahland, M Fatyga, MK Fatyga

Abstract:

We present results on the search for the top quark in pp̄ collisions at s =1.8 TeV with an integrated luminosity of 13.5±1.6 pb-1. We have considered tt̄ production in the standard model using electron and muon dilepton decay channels (tt̄→eμ+jets, ee+jets, and μμ+jets) and single-lepton decay channels (tt̄→e+jets and μ+jets) with and without tagging of b quark jets. An analysis of these data optimized for top quark masses below 140 GeV/c2 gives a lower top quark mass limit of 128 GeV/c2. An analysis optimized for higher top quark masses yields 9 events with an expected background of 3.8±0.9. If we assume that the excess is due to tt̄ production, and assuming a top quark mass of 180 GeV/c2, we obtain a cross section of 8.2±5.1 pb.

Ultrahigh energy cosmic ray composition from surface air shower and underground muon measurements at Soudan 2

Physical Review D 52:5 (1995) 2760-2765

Authors:

NP Longley, CR Bode, PM Border, H Courant, DM Demuth, RN Gray, K Johns, SMS Kasahara, MJ Lowe, ML Marshak, WH Miller, L Mualem, EA Peterson, DM Roback, K Ruddick, DJ Schmid, MH Schub, MA Shupe, V Vassiliev, G Villaume, SJ Werkema, DS Ayres, TH Fields, HM Gallagher, MC Goodman, FV Lopez, EN May, LE Price, RV Seidlein, JL Thron, HJ Trost, JL Uretsky, WWM Allison, GD Barr, CB Brooks, JH Cobb, GL Giller, A Stassinakis, MA Thomson, N West, U Wielgosz, GJ Alner, DJA Cockerill, RJ Cotton, C Garcia-Garcia, PJ Litchfield, GF Pearce, B Ewen, T Kafka, J Kochocki, W Leeson, WA Mann, RH Milburn, A Napier, W Oliver, B Saitta, J Schneps, N Sundaralingam, WL Barrett

Abstract:

The Soudan 2 experiment has performed time-coincident cosmic ray air shower and underground muon measurements. Comparisons to Monte Carlo predictions show that such measurements can make statistically significant tests of the primary composition in the knee region of the cosmic ray spectrum. The results do not 91̽ any significant increase in the average primary mass with energy in the range of 104 TeV per nucleus. Some systematic uncertainties remain, however, particularly in the Monte Carlo modeling of the cosmic ray shower. © 1995 The American Physical Society.

W and Z boson production in pp̄ collisions at s=1.8 TeV

Physical Review Letters 75:8 (1995) 1456-1461

Authors:

S Abachi, B Abbott, M Abolins, BS Acharya, I Adam, DL Adams, M Adams, S Ahn, H Aihara, J Alitti, G Alvarez, GA Alves, E Amidi, N Amos, EW Anderson, SH Aronson, R Astur, RE Avery, A Baden, V Balamurali, J Balderston, B Baldin, J Bantly, JF Bartlett, K Bazizi, J Bendich, SB Beri, I Bertram, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, A Bischoff, N Biswas, G Blazey, S Blessing, P Bloom, A Boehnlein, NI Bojko, F Borcherding, J Borders, C Boswell, A Brandt, R Brock, A Bross, D Buchholz, VS Burtovoi, JM Butler, D Casey, H Castilla-Valdez, D Chakraborty, SM Chang, SV Chekulaev, LP Chen, W Chen, L Chevalier, S Chopra, BC Choudhary, JH Christenson, M Chung, D Claes, AR Clark, WG Cobau, J Cochran, WE Cooper, C Cretsinger, D Cullen-Vidal, MAC Cummings, D Cutts, OI Dahl, K De, M Demarteau, R Demina, K Denisenko, N Denisenko, D Denisov, SP Denisov, W Dharmaratna, HT Diehl, M Diesburg, G Di Loreto, R Dixon, P Draper, J Drinkard, Y Ducros, SR Dugad, S Durston-Johnson, D Edmunds, J Ellison, VD Elvira, R Engelmann, S Eno, G Eppley, P Ermolov, OV Eroshin, VN Evdokimov, S Fahey, T Fahland, M Fatyga, MK Fatyga

Abstract:

The inclusive cross sections times leptonic branching ratios for W and Z boson production in pp̄ collisions at s=1.8 TeV were measured using the D0 detector at the Fermilab Tevatron collider: σWB(W→eν)=2. 36±0.07±0.13 nb, σWBW→μν=2.09±0. 23±0.11 nb, σZBZ→e+e-=0.218±0.011±0.012 nb, and σZBZ→μ+μ-=0.178±0.030±0.009 nb. The first error is the combined statistical and systematic uncertainty, and the second reflects the uncertainty in the luminosity. For the combined electron and muon analyses we find σWB(W→lν)/σZB(Z→l+l-)=10.90±0.49. Assuming standard model couplings, this result is used to determine the width of the W boson, γ(W)=2.044±0.093 GeV. © 1995 The American Physical Society.