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First observation of the all-hadronic decay of tt― pairs

Physical Review Letters 79:11 (1997) 1992-1997

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, 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, M Barone, E 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, B Bevensee, A Bhatti, K Biery, M Binkley, D Bisello, RE Blair, C Blocker, A Bodek, W Bokhari, V Bolognesi, G Bolla, D Bortoletto, J Boudreau, L Breccia, C Bromberg, N Bruner, 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, D Cauz, Y Cen, F Cervelli, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, 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, F DeJongh, S Delchamps, S Dell’agnello, M Dell’orso, R Demina, L Demortier

Abstract:

We present the first observation of the all hadronic decay of tt― pairs. The analysis is performed using 109 pb−1 of pp― collisions at s = 1.8 TeV collected with the Collider Detector at Fermilab. We observe an excess of events with five or more jets, including one or two b jets, relative to background expectations. Based on this excess we evaluate the production cross section to be in agreement with previous results. We measure the top mass to be 186±10±12 GeV/c2. © 1997 The American Physical Society.

Limits on quark-lepton compositeness scales from dileptons produced in 1.8 TeV pp-collisions

Physical Review Letters 79:12 (1997) 2198-2203

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, 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, M Barone, E 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, B Bevensee, A Bhatti, K Biery, M Binkley, D Bisello, RE Blair, C Blocker, A Bodek, W Bokhari, V Bolognesi, G Bolla, D Bortoletto, J Boudreau, L Breccia, C Bromberg, N Bruner, 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, D Cauz, Y Cen, F Cervelli, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, 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, F DeJongh, S Delchamps, S Dell’agnello, M Dell’orso, R Demina, L Demortier

Abstract:

The dilepton mass spectrum in pp-→|+|-+X interactions is studied using dielectrons (ee) and dimuons (μμ) in 100 pb- of data collected with the Collider Detector at Fermilab. The data are consistent with standard model predictions. The mass spectrum, being a probe for new physics, is examined for new interactions of quarks and leptons from a common composite structure. Assuming a contact interaction with the conventional coupling g20/4π = 1, limits on chiral quark-electron and quark-muon compositeness scales in the range of 2.5 to 4.2 TeV are obtained. © 1997 The American Physical Society.

Measurement of Diffractive Dijet Production at the Fermilab Tevatron

Physical Review Letters 79:14 (1997) 2636-2641

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, 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, M Barone, E 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, B Bevensee, A Bhatti, K Biery, M Binkley, D Bisello, RE Blair, C Blocker, A Bodek, W Bokhari, V Bolognesi, G Bolla, D Bortoletto, J Boudreau, L Breccia, C Bromberg, N Bruner, 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, D Cauz, Y Cen, F Cervelli, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, 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, F DeJongh, S Delchamps, S Dell'Agnello, M Dell'Orso, R Demina, L Demortier

Abstract:

We report the observation and measurement of the rate of diffractive dijet production at the Fermilab Tevatron p¯p collider at √s=1.8TeV. In events with two jets of ET>20GeV, 1.8<|η|<3.5, and η1η2>0, we find that the diffractive to nondiffractive production ratio is RJJ=[0.75±0.05(stat)±0.09(syst)]%. By comparing this result, in combination with our measured rate for diffractive W boson production reported previously, with predictions based on a hard partonic pomeron structure, we determine the pomeron gluon fraction to be fg=0.7±0.2. © 1997 American Physical Society.

Measurement of the B¯→D¯ partial width and form factor parameters

Physical Review Letters 79:12 (1997) 2208-2212

Authors:

M Athanas, P Avery, CD Jones, M Lohner, C Prescott, J Yelton, J Zheng, G Brandenburg, RA Briere, A Ershov, YS Gao, DYJ Kim, R Wilson, H Yamamoto, TE Browder, F Li, Y Li, JL Rodriguez, T Bergfeld, BI Eisenstein, J Ernst, GE Gladding, GD Gollin, RM Hans, E Johnson, I Karliner, MA Marsh, M Palmer, M Selen, JJ Thaler, KW Edwards, A Bellerive, R Janicek, DB MacFarlane, PM Patel, AJ Sadoff, R Ammar, P Baringer, A Bean, D Besson, D Coppage, C Darling, R Davis, N Hancock, S Kotov, I Kravchenko, N Kwak, Y Kubota, SJ Lee, JJ O’neill, S Patton, R Poling, T Riehle, V Savinov, A Smith, MS Alam, SB Athar, Z Ling, AH Mahmood, H Severini, S Timm, F Wappler, A Anastassov, S Blinov, JE Duboscq, D Fujino, KK Gan, T Hart, K Honscheid, H Kagan, R Kass, J Lee, MB Spencer, M Sung, A Undrus, R Wanke, A Wolf, MM Zoeller, B Nemati, SJ Richichi, WR Ross, P Skubic, M Bishai, J Fast, E Gerndt, JW Hinson, N Menon, DH Miller, EI Shibata, IPJ Shipsey, M Yurko, L Gibbons, S Glenn, SD Johnson, Y Kwon, S Roberts, EH Thorndike, CP Jessop, K Lingel, H Marsiske

Abstract:

We have studied the decayB¯→Dlν¯ where l = e or μ. From a fit to the differential decay ratedγ/dwwe measure the rate normalizationFD(1) |V cb | and form factor slopeρˆ2D, and, using measured values ofτB, findγ(B¯→D¯) = (12.0 ± 0.9 ± 2.1) ns−1 . The resulting branching fractions areB (B¯0 → D+ l−ν¯) = (1.87 ± 0.15 ± 0.32)% and B (B− → D0l−ν¯) = (1.94 ± 0.15 ± 0.34)% . The form factor parameters are in agreement with those measured in B¯ → D*l−ν¯ decays, as predicted by heavy quark effective theory. © 1997 The American Physical Society.

Measurement of the direct photon spectrum in [Formula presented] decays

Physical Review D - Particles, Fields, Gravitation and Cosmology 55:9 (1997) 5273-5281

Authors:

B Nemati, SJ Richichi, WR Ross, P Skubic, M Wood, M Bishai, J Fast, E Gerndt, JW Hinson, N Menon, DH Miller, EI Shibata, IPJ Shipsey, M Yurko, L Gibbons, SD Johnson, Y Kwon, S Roberts, EH Thorndike, CP Jessop, K Lingel, H Marsiske, ML Perl, SF Schaffner, D Ugolini, R Wang, X Zhou, TE Coan, V Fadeyev, I Korolkov, Y Maravin, I Narsky, V Shelkov, J Staeck, R Stroynowski, I Volobouev, J Ye, M Artuso, A Efimov, F Frasconi, M Gao, M Goldberg, D He, S Kopp, GC Moneti, R Mountain, Y Mukhin, S Schuh, T Skwarnicki, S Stone, G Viehhauser, X Xing, J Bartelt, SE Csorna, V Jain, S Marka, A Freyberger, D Gibaut, R Godang, K Kinoshita, IC Lai, P Pomianowski, S Schrenk, G Bonvicini, D Cinabro, R Greene, LP Perera, B Barish, M Chadha, S Chan, G Eigen, JS Miller, C O’Grady, M Schmidtler, J Urheim, AJ Weinstein, F Würthwein, DM Asner, DW Bliss, WS Brower, G Masek, HP Paar, M Sivertz, V Sharma, J Gronberg, R Kutschke, DJ Lange, S Menary, RJ Morrison, HN Nelson, TK Nelson, C Qiao, JD Richman, D Roberts, A Ryd, MS Witherell, R Balest, BH Behrens, K Cho, WT Ford

Abstract:

Using data taken with the CLEO II detector at the Cornell Electron Storage Ring, we have determined the ratio of branching fractions: [Formula presented]. From this ratio, we have determined the QCD scale parameter [Formula presented] (defined in the modified minimal subtraction scheme) to be [Formula presented] MeV, from which we determine a value for the strong coupling constant [Formula presented], or [Formula presented]. © 1997 The American Physical Society.