Measurement of the top quark pT distribution

Physical Review Letters 87:10 (2001)

Authors:

T Affolder, H Akimoto, A Akopian, MG Albrow, P Amaral, SR Amendolia, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, T Asakawa, W Ashmanskas, F Azfar, P Azzi-Bacchetta, N Bacchetta, MW Bailey, S Bailey, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, M Barone, G Bauer, F Bedeschi, S Belforte, WH Bell, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, B Bevensee, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, SR Blusk, A Bocci, A Bodek, W Bokhari, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, S van den Brink, C Bromberg, M Brozovic, N Bruner, E Buckley-Geer, J Budagov, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, P Calafiura, M Campbell, W Carithers, J Carlson, D Carlsmith, W Caskey, J Cassada, A Castro, D Cauz, A Cerri, AW Chan, PS Chang, PT Chang, J Chapman, C Chen, YC Chen, MT Cheng, M Chertok, G Chiarelli, I Chirikov-Zorin, G Chlachidze, F Chlebana, L Christofek, ML Chu, YS Chung, CI Ciobanu, AG Clark, A Connolly, J Conway, M Cordelli, J Cranshaw, D Cronin-Hennessy, R Cropp, R Culbertson, D Dagenhart, S D'Auria

Abstract:

The first measurement of the true top quark PT distributon was carried out. An attempt was also made to compute a 95% confidence level upper limit on the fraction of top quarks that are produced with 225 > PT > 425 GeV/c. It was found that R4 > 0.16 at 95% C.L.

Measurement of the quadratic slope parameter in the KL → 3π0 decay Dalitz plot

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 515:3-4 (2001) 261-268

Authors:

A Lai, D Marras, L Musa, A Bevan, RS Dosanjh, TJ Gershon, B Hay, GE Kalmus, DJ Munday, MD Needham, E Olaiya, MA Parker, TO White, SA Wotton, G Barr, H Blümer, G Bocquet, A Ceccucci, D Cundy, G D'Agostini, N Doble, V Falaleev, L Gatignon, A Gonidec, G Govi, P Grafström, W Kubischta, A Lacourt, M Lenti, S Luitz, JP Matheys, A Norton, S Palestini, B Panzer-Steindel, G Tatishvili, H Taureg, M Velasco, H Wahl, C Cheshkov, P Hristov, V Kekelidze, D Madigojine, N Molokanova, Y Potrebenikov, A Zinchenko, I Knowles, C Lazzeroni, V Martin, H Parsons, R Sacco, A Walker, M Contalbrigo, P Dalpiaz, J Duclos, PL Frabetti, A Gianoli, M Martini, F Petrucci, M Savrié, A Bizzeti, M Calvetti, G Collazuol, G Graziani, E Iacopini, HG Becker, M Eppard, H Fox, K Holtz, A Kalter, K Kleinknecht, U Koch, L Köpke, I Pellmann, A Peters, B Renk, SA Schmidt, V Schönharting, Y Schué, R Wanke, A Winhart, M Wittgen, JC Chollet, S Crépé, L Fayard, L Iconomidou-Fayard, J Ocariz, G Unal, I Wingerter, G Anzivino, P Cenci, E Imbergamo, P Lubrano, A Mestvirishvili, A Nappi, M Pepe, M Piccini, R Carosi, R Casali, C Cerri, M Cirilli

Abstract:

A value of (-6.1 ± 0.9stat ± 0.5syst) × 10-3 is obtained for the quadratic slope parameter h in the KL → 3π0 decay Dalitz plot at the NA48 experiment at the CERN SPS. The result is based on 14.7 × 106 fully reconstructed KL → 3π0 → 6γ decays. This is the most precise measurement of any of the Dalitz plot slope parameters in the charged and neutral kaon decays so far. © 2001 Elsevier Science B.V.

Search for the supersymmetric partner of the top quark in pp̄ collisions at √s=1.8 TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 63:9 (2001) 911011-911016

Authors:

T Affolder, H Akimoto, A Akopian, MG Albrow, P Amaral, SR Amendolia, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, T Asakawa, W Ashmanskas, F Azfar, P Azzi-Bacchetta, N Bacchetta, MW Bailey, S Bailey, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, M Barone, G Bauer, F Bedeschi, S Belforte, WH Bell, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, B Bevensee, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, SR Blusk, A Bocci, A Bodek, W Bokhari, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, S van den Brink, C Bromberg, M Brozovic, N Bruner, E Buckley-Geer, J Budagov, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, P Calafiura, M Campbell, W Carithers, J Carlson, D Carlsmith, W Caskey, J Cassada, A Castro, D Cauz, A Cerri, AW Chan, PS Chang, PT Chang, J Chapman, C Chen, YC Chen, MT Cheng, M Chertok, G Chiarelli, I Chirikov-Zorin, G Chlachidze, F Chlebana, L Christofek, ML Chu, YS Chung, CI Ciobanu, AG Clark, A Connolly, J Conway, M Cordelli, J Cranshaw, D Cronin-Hennessy, R Cropp, R Culbertson, D Dagenhart

Abstract:

We report on a search for the supersymmetric partner of the top quark (top squark) produced in tt̄ events using 110 pb-1 of pp̄ collisions at √s = 1.8 TeV recorded with the Collider Detector at Fermilab. In the case of a light top squark, the decay of the top quark into a top squark plus the lightest supersymmetric particle (LSP) could have a significant branching ratio. The observed events are consistent with standard model tt̄ production and decay. Hence, we set limits on the branching ratio of the top quark decaying into a top squark plus LSP, excluding branching ratios above 45% for a LSP mass up to 40 GeV/c2.

Tests of enhanced leading order QCD in W boson plus jets events from 1.8 TeV p̄p collisions

Physical Review D - Particles, Fields, Gravitation and Cosmology 63:7 (2001) 720031-7200329

Authors:

T Affolder, H Akimoto, A Akopian, MG Albrow, P Amaral, SR Amendolia, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, T Asakawa, W Ashmanskas, F Azfar, P Azzi-Bacchetta, N Bacchetta, MW Bailey, S Bailey, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, M Barone, G Bauer, F Bedeschi, S Belforte, WH Bell, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, B Bevensee, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, SR Blusk, A Bocci, A Bodek, W Bokhari, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, S van den Brink, C Bromberg, M Brozovic, N Bruner, E Buckley-Geer, J Budagov, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, P Calafiura, M Campbell, W Carithers, J Carlson, D Carlsmith, J Cassada, A Castro, D Cauz, A Cerri, AW Chan, PS Chang, PT Chang, J Chapman, C Chen, YC Chen, MT Cheng, M Chertok, G Chiarelli, I Chirikov-Zorin, G Chlachidze, F Chlebana, L Christofek, ML Chu, YS Chung, CI Ciobanu, AG Clark, A Connolly, J Conway, J Cooper, M Cordelli, J Cranshaw, D Cronin-Hennessy, R Cropp, R Culbertson, D Dagenhart, S D'Auria

Abstract:

We present a study of events with W bosons and hadronic jets produced in p̄p collisions at a center of mass energy of 1.8 TeV. The data consist of 51400 W → e ν decay candidates from 108 pb-1 of integrated luminosity collected using the CDF detector at the Fermilab Tevatron collider. Cross sections and jet production properties have been measured for W + ≥ 1 to ≥ 4 jet events. The data compare well to predictions of leading-order QCD matrix element calculations with added gluon radiation and simulated parton fragmentation.

Search for heavy particles decaying into electron-positron pairs in pp̄ collisions

Physical Review Letters 87:6 (2001) 618021-618026

Authors:

VM Abazov, B Abbott, A Abdesselam, M Abolins, V Abramov, BS Acharya, DL Adams, M Adams, SN Ahmed, GD Alexeev, GA Alves, N Amos, EW Anderson, MM Baarmand, VV Babintsev, L Babukhadia, TC Bacon, A Baden, B Baldin, PW Balm, S Banerjee, E Barberis, P Baringer, J Barreto, JF Bartlett, U Bassler, D Bauer, A Bean, M Begel, A Belyaev, SB Beri, G Bernardi, I Bertram, A Besson, R Beuselinck, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, G Blazey, S Blessing, A Boehnlein, NI Bojko, F Borcherding, K Bos, A Brandt, R Breedon, G Briskin, R Brock, G Brooijmans, A Bross, D Buchholz, M Buehler, V Buescher, VS Burtovoi, JM Butler, F Canelli, W Carvalho, D Casey, Z Casilum, H Castilla-Valdez, D Chakraborty, KM Chan, SV Chekulaev, DK Cho, S Choi, S Chopra, JH Christenson, M Chung, D Claes, AR Clark, J Cochran, L Coney, B Connolly, WE Cooper, D Coppage, MAC Cummings, D Cutts, GA Davis, K Davis, K De, SJ De Jong, K Del Signore, M Demarteau, R Demina, P Demine, D Denisov, SP Denisov, S Desai, HT Diehl, M Diesburg, G Di Loreto, S Doulas, P Draper, Y Ducros, LV Dudko, S Duensing, L Duflot, SR Dugad, A Dyshkant

Abstract:

The data collected by DO detector was used to study the decay of heavy particles into electron-positron pairs during collisions. The dielectron invariant mass spectra for the events with both electrons in central region and with one electron in central region and other in forward region of central calorimeter (CC)/end calorimeter (EC) were also studied. PYTHIA was used to determine the product of cross section and branching ratio for the system. The superimposed histograms represented the estimated spectrum from standard model processes and instrumental effects.