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Measurement of [formula presented] rapidity correlations in [formula presented] collisions at [formula presented]

Physical Review D - Particles, Fields, Gravitation and Cosmology 61:3 (2000)

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 Barbaro, 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 Bokhari, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, L Breccia, C Bromberg, N Bruner, 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 report the first direct measurement of (Formula presented) rapidity correlations in (Formula presented) collisions at (Formula presented) We select events with a high transverse momentum muon accompanied by a jet, and a second jet associated with a decay vertex displaced from the (Formula presented) interaction vertex. Two independent samples are obtained corresponding to events with a forward (Formula presented) or central (Formula presented) muon. We measure the ratio of forward to central (Formula presented) production to be (Formula presented) in good agreement with the next-to-leading order QCD prediction (Formula presented) © 1999 The American Physical Society.
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Measurement of the helicity of W bosons in top quark decays

Physical review letters 84:2 (2000) 216-221

Authors:

F Ukegawa, J Valls, S Vejcik, G Velev, R Vidal, R Vilar, I Vologouev, D Vucinic, RG Wagner, RL Wagner, J Wahl, NB Wallace, AM Walsh, C Wang, CH Wang, MJ Wang, T Watanabe, T Watts, R Webb, H Wenzel, WC Wester, AB Wicklund, E Wicklund, HH Williams, P Wilson, BL Winer

Abstract:

We use the transverse momentum spectrum of leptons in the decay chain t-->bW with W-->lnu to measure the helicity of the W bosons in the top quark rest frame. Our measurement uses a t&tmacr; sample isolated in 106+/-4 pb(-1) of data collected in p&pmacr; collisions at sqrt[s] = 1.8 TeV with the CDF detector at the Fermilab Tevatron. Assuming a standard V-A weak decay, we find that the fraction of W's with zero helicity in the top rest frame is F0 = 0.91+/-0. 37(stat)+/-0.13(syst), consistent with the standard model prediction of F0 = 0.70 for a top mass of 175 GeV/c(2).
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Observation of diffractive b-quark production at the fermilab tevatron

Physical review letters 84:2 (2000) 232-237

Authors:

F Ukegawa, J Valls, S Vejcik, G Velev, R Vidal, R Vilar, I Vologouev, D Vucinic, RG Wagner, RL Wagner, J Wahl, NB Wallace, AM Walsh, C Wang, CH Wang, MJ Wang, T Watanabe, T Watts, R Webb, H Wenzel, WC Wester, AB Wicklund, E Wicklund, HH Williams, P Wilson, BL Winer

Abstract:

We report a measurement of the fraction of b quarks produced diffractively in &pmacr;p collisions at sqrt[s] = 1.8 TeV. Diffraction is identified by the absence of particles in a forward pseudorapidity region. From events with an electron of transverse momentum 9.5
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Observation of radiative leptonic decay of the tau lepton

Physical review letters 84:5 (2000) 830-834

Authors:

G Viehhauser, JC Wang, A Wolf, J Wu, SE Csorna, KW McLean, S Marka, Z Xu, R Godang, K Kinoshita, IC Lai, S Schrenk, G Bonvicini, D Cinabro, R Greene, LP Perera, GJ Zhou, S Chan, G Eigen, E Lipeles, M Schmidtler, A Shapiro, WM Sun, J Urheim, AJ Weinstein, F Wurthwein

Abstract:

Using 4.68 fb(-1) of e(+)e(-) annihilation data collected with the CLEO II detector at the Cornell Electron Storage Ring, we have studied tau radiative decays tau(-)-->nu(tau)&mgr;(-)nu;(&mgr;)gamma and tau(-)-->nu(tau)e(-)nu;(e)gamma. For a 10 MeV minimum photon energy in the tau rest frame, the branching fraction for radiative tau decay to a muon or electron is measured to be (3.61+/-0.16+/-0. 35)x10(-3) or (1.75+/-0.06+/-0.17)x10(-2), respectively. The branching fractions are in agreement with standard model theoretical predictions.
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Search for a fourth-generation quark more massive than the Z0 boson in p&pmacr; collisions at radicals = 1.8 TeV

Physical review letters 84:5 (2000) 835-840

Authors:

W Trischuk, de Troconiz JF, S Truitt, J Tseng, N Turini, F Ukegawa, J Valls, S Vejcik, G Velev, R Vidal, R Vilar, I Vologouev, D Vucinic, RG Wagner, RL Wagner, J Wahl, NB Wallace, AM Walsh, C Wang, CH Wang, MJ Wang, T Watanabe, D Waters, T Watts, R Webb, H Wenzel

Abstract:

We present the results of a search for pair production of a fourth-generation charge -1 / 3 quark (b(')) in sqrt[s] = 1.8 TeV p&pmacr; collisions using 88 pb(-1) of data obtained with the Collider Detector at Fermilab. We assume that both quarks decay via the flavor-changing neutral current process b(')-->bZ(0) and that the b(') mass is greater than m(Z)+m(b). We studied the decay mode b(')b(');-->Z(0)Z(0)b&bmacr; where one Z0 decays into e(+)e(-) or &mgr;(+)&mgr;(-) and the other decays hadronically, giving a signature of two leptons plus jets. An upper limit on the sigma(p&pmacr;-->b(')b(');)x[B(b(')-->bZ(0))](2) is established as a function of the b(') mass. We exclude at 95% confidence level a b(') quark with mass between 100 and 199 GeV/c(2) for B(b(')-->bZ(0)) = 100%.
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