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Limit on the tau neutrino mass from τ→π-π+π-π 0ντ

Physical Review D 61:5 (2000)

Authors:

M Athanas, P Avery, CD Jones, M Lohner, C Prescott, AI Rubiera, J Yelton, J Zheng, G Brandenburg, RA Briere, A Ershov, YS Gao, DYJ Kim, R Wilson, TE Browder, Y Li, JL Rodriguez, H Yamamoto, T Bergfeld, BI Eisenstein, J Ernst, GE Gladding, GD Gollin, RM Hans, E Johnson, I Karliner, MA Marsh, M Palmer, C Plager, C Sedlack, M Selen, JJ Thaler, J Williams, KW Edwards, R Janicek, PM Patel, AJ Sadoff, R Ammar, P Baringer, A Bean, D Besson, D Coppage, R Davis, S Kotov, I Kravchenko, N Kwak, X Zhao, L Zhou, S Anderson, VV Frolov, Y Kubota, SJ Lee, R Mahapatra, JJ O'Neill, R Poling, T Riehle, A Smith, MS Alam, SB Athar, AH Mahmood, S Timm, F Wappler, A Anastassov, JE Duboscq, KK Gan, C Gwon, T Hart, K Honscheid, H Kagan, R Kass, J Lorenc, H Schwarthoff, E von Toerne, MM Zoeller, SJ Richichi, H Severini, P Skubic, A Undrus, M Bishai, S Chen, J Fast, JW Hinson, J Lee, N Menon, DH Miller, EI Shibata, IPJ Shipsey, S Glenn, Y Kwon, AL Lyon, EH Thorndike, CP Jessop, K Lingel, H Marsiske, ML Perl, V Savinov, D Ugolini, X Zhou, TE Coan, V Fadeyev

Abstract:

From a data sample of 29058 τ+→π±π+π -π0ντdecays observed in the CLEO detector we derive a 95% confidence upper limit on the tau neutrino mass of 28 MeV. ©2000 The American Physical Society.
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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 elastic cross section for cold cesium collisions

Physical Review A - Atomic, Molecular, and Optical Physics 61:3 (2000) 327071-327074

Authors:

SA Hopkins, S Webster, J Arlt, P Bance, S Cornish, O Maragò, CJ Foot

Abstract:

We have measured the time taken for a magnetically trapped cloud of cold cesium atoms in the (F =3,mF=-3) ground state to rethermalize from a nonequilibrium spatial and velocity distribution. From these measurements we infer the dependences of the elastic scattering cross section on temperature and magnetic field in the ranges 1 - 30 μΚ and 0.05-2.0 mT, respectively. We determine a lower bound on the magnitude of the (3,-3) + (3,-3) s-wave scattering length of 940a0.
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The search for extra dimensions

Physics World 13:11 (2000) 39-44

Authors:

S Abel, J March-Russell

Abstract:

Steven Abel and John March-Russell discuss whether three dimensions exist in the universe and how they can be detected. Explaining why the cosmological constant is so small has occupied cosmologists and particle physicists ever since Einstein first introduced it. Many proponents of the brane-world picture are tackling this problem again. A typical process might involve a proton and antiproton colliding to produce a single spray or jet of particles plus a graviton, which is emitted into the bulk. The particles that are confined to the brane also have Kaluza - Klein or higher string-excitation states, but for them the relevant scale is either the brane thickness or the new fundamental string scale. Both of these scales should correspond in energy to the new gravity scale of 1000 GeV or higher.
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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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