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Kinematics of tt̄ events at CDF

Physical Review D - Particles, Fields, Gravitation and Cosmology 59:9 (1999) 1-20

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, A Amadon, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, T Arisawa, T Asakawa, W Ashmanskas, M Atac, P Azzi-Bacchetta, N Bacchetta, S Bagdasarov, MW Bailey, P De Barbara, A Barbaro-Galtieri, VE Barnes, BA Barnett, M Barone, G Bauer, T Baumann, F Bedeschi, S Behrends, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, S Bertolucci, S Bettelli, B Bevensee, A Bhatti, K Biery, C Bigongiari, M Binkley, D Bisello, RE Blair, C Blocker, K Bloom, S Blusk, A Bodek, W Bikhari, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, L Breccia, C Bromberg, N Burner, R Brunetti, E Buckley-Geer, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, M Campbell, A Caner, W Carithers, D Carlsmith, J Cassada, A Castro, D Cauz, A Cerri, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, M Chertok, G Chiarelli, CN Chiou, F Chlebana, L Christofek, R Cropp, ML Chu, S Cihangir, AG Clark, M Cobal, E Cocca, M Contreras, J Conway, J Cooper, M Cordelli, D Costanzo, C Couyoumtzelis, D Cronin-Hennessy, R Culbertson, D Dagenhart, T Daniels, F DeJongh, S Dell'Agnello, M Dell'Orso

Abstract:

The kinematic properties of tt̄ events are studied in the W+ multijet channel using data collected with the CDF detector during the 1992-1995 runs at the Fermilab Tevatron collider corresponding to an integrated luminosity of 109 pb-1. Distributions of a variety of kinematic variables chosen to be sensitive to different aspects of tt̄ production are compared with those expected from Monte Carlo calculations. A sample of 34 events rich in tt̄ pairs is obtained by requiring at least one jet identified by the silicon vertex detector (SVX) as having a displaced vertex consistent with the decay of a b hadron. The data are found to be in good agreement with predictions of the leading order tt̄ matrix element with color coherent parton shower evolution. ©1999 The American Physical Society.
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Searches for new physics in diphoton events in pp̄ collisions at √s = 1.8 TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 59:9 (1999) 1-29

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, A Amadon, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, T Arisawa, T Asakawa, W Ashmanskas, M Atac, P Azzi-Bacchetta, N Bacchetta, S Bagdasarov, MW Bailey, P De Barbara, A Barbaro-Galtieri, VE Barnes, BA Barnett, M Barone, G Bauer, T Baumann, F Bedeschi, S Behrends, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, S Bertolucci, S Bettelli, B Bevensee, A Bhatti, K Biery, C Bigongiari, M Binkley, D Bisello, RE Blair, C Blocker, K Bloom, S Blusk, A Bodek, W Bikhari, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, L Breccia, C Bromberg, N Burner, R Brunetti, E Buckley-Geer, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, M Campbell, A Caner, W Carithers, D Carlsmith, J Cassada, A Castro, D Cauz, A Cerri, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, M Chertok, G Chiarelli, CN Chiou, F Chlebana, L Christofek, R Cropp, ML Chu, S Cihangir, AG Clark, M Cobal, E Cocca, M Contreras, J Conway, J Cooper, M Cordelli, D Costanzo, C Couyoumtzelis, D Cronin-Hennessy, R Culbertson, D Dagenhart, T Daniels, F DeJongh, S Dell'Agnello, M Dell'Orso

Abstract:

We present a detailed description of a search for anomalous production of missing ET (Slashed E signT), jets, leptons (e, μ, τ), b quarks, or additional photons in events containing two isolated, central (|η|<1.0) photons with ET>12 GeV. The results are consistent with standard model expectations, with the possible exception of one event that has, in addition to the two photons, a central electron, a high-ET electromagnetic cluster, and large Slashed E signT. We set limits using two specific SUSY scenarios for production of diphoton events with Slashed E signT. ©1999 The American Physical Society.
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Measurement of multiplicity and momentum spectra in the current and target regions of the Breit frame in Deep Inelastic Scattering at HERA

ArXiv hep-ex/9903056 (1999)
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Determination of the absolute jet energy scale in the DO calorimeters

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 424:2 (1999) 352-394

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, L Babukhadia, A Baden, V Balamurali, J Balderston, B Baldin, S Banerjee, J Bantly, E Barberis, 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 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 Elvirai, R Engelmann, S Eno, G Eppley, P Ermolov, OV Eroshin, VN Evdokimov, T Fahland, MK Fatyga, S Feherg, D Fein, T Ferbel, G Finocchiaro, HE Fisk, Y Fisyak, E Flattum, GE Forden

Abstract:

The DO detector is used to study pp collisions at the 1800 and 630 GeV center-of-mass energies available at the Fermilab Tevatron. To measure jets, the detector uses a sampling calorimeter composed of uranium and liquid argon as the passive and active media, respectively, Understanding the jet energy calibration is not only crucial for precision tests of QCD, but also for the measurement of particle masses and the determination of physics backgrounds associated with new phenomena. This paper describes the energy calibration of jets observed with the DO detector at the two pp center-of-mass energies in the transverse energy and pseudorapidity range ET>8 GeV and |η|<3.
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Irradiation tests of photodiodes for the ATLAS SCT readout

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 424:2 (1999) 483-494

Authors:

JD Dowell, RJ Homer, IR Kenyon, G Mahout, SJ Oglesby, HR Shaylor, JA Wilson, RB Nickerson, R Wastie, AR Weidberg

Abstract:

Two kinds of photodiodes have been investigated for the ATLAS SCT readout. We present in this paper the results of irradiating bulk and epitaxial Si PIN diodes with 1 MeV-equivalent neutrons and 24 GeV protons. The devices were biased during some of the tests. They were exposed to a fluence of around 2.5×1014 n cm-2 followed by a fluence of approximately 2.5×1014 p cm-2.
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