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Search for heavy toplike quarks using lepton plus jets events in 1.96 TeV pp̄ collisions

Physical Review Letters 100:16 (2008)

Authors:

T Aaltonen, J Adelman, T Akimoto, MG Albrow, B Álvarez González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, M Aoki, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzi-Bacchetta, P Azzurri, N Bacchetta, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, P Bednar, S Behari, G Bellettini, J Bellinger, A Belloni, D Benjamin, A Beretvas, J Beringer, T Berry, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, A Bolshov, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, M Campanelli, M Campbell, F Canelli, A Canepa, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, G Choudalakis, SH Chuang, K Chung, WH Chung, YS Chung, CI Ciobanu

Abstract:

We present the results of a search for pair production of a new heavy toplike quark t′ decaying to a W boson and another quark using the Collider Detector at FermilabII detector in runII of the Tevatron pp̄ collider. Using a data sample corresponding to 760pb-1 of integrated luminosity, we fit the observed spectrum of total transverse energy and reconstructed t′ quark mass to a combination of standard model processes and t′ pair production. We see no evidence for t′t̄′ production, and we infer a lower limit of 256GeV/c2 on the mass of the t′ at 95% C.L. assuming standard strong couplings for the t′. © 2008 The American Physical Society.
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Measurement of the absolute branching fraction of Ds+→τ+ντ decay

Physical Review Letters 100:16 (2008)

Authors:

KM Ecklund, W Love, V Savinov, A Lopez, H Mendez, J Ramirez, JY Ge, DH Miller, IPJ Shipsey, B Xin, GS Adams, M Anderson, JP Cummings, I Danko, D Hu, B Moziak, J Napolitano, Q He, J Insler, H Muramatsu, CS Park, EH Thorndike, F Yang, M Artuso, S Blusk, S Khalil, J Li, R Mountain, S Nisar, K Randrianarivony, N Sultana, T Skwarnicki, S Stone, JC Wang, LM Zhang, G Bonvicini, D Cinabro, M Dubrovin, A Lincoln, J Rademacker, DM Asner, KW Edwards, P Naik, J Reed, RA Briere, T Ferguson, G Tatishvili, H Vogel, ME Watkins, JL Rosner, JP Alexander, DG Cassel, JE Duboscq, R Ehrlich, L Fields, L Gibbons, R Gray, SW Gray, DL Hartill, BK Heltsley, D Hertz, CD Jones, J Kandaswamy, DL Kreinick, VE Kuznetsov, H Mahlke-Krüger, D Mohapatra, PUE Onyisi, JR Patterson, D Peterson, D Riley, A Ryd, AJ Sadoff, X Shi, S Stroiney, WM Sun, T Wilksen, SB Athar, R Patel, J Yelton, P Rubin, BI Eisenstein, I Karliner, S Mehrabyan, N Lowrey, M Selen, EJ White, J Wiss, RE Mitchell, MR Shepherd, D Besson, TK Pedlar, D Cronin-Hennessy, KY Gao, J Hietala, Y Kubota, T Klein, BW Lang, R Poling, AW Scott

Abstract:

Using a sample of tagged Ds+ decays collected near the Ds*±Ds peak production energy in e+e- collisions with the CLEO-c detector, we study the leptonic decay Ds+→τ+ντ via the decay channel τ+→e+νeν̄τ. We measure B(Ds+→τ+ντ)=(6. 17±0.71±0.34)%, where the first error is statistical and the second systematic. Combining this result with our measurements of Ds+→μ+νμ and Ds+→τ+ντ (via τ+→π+ν ̄τ), we determine fDs=(274±10±5)MeV. © 2008 The American Physical Society.
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Measurement of ratios of fragmentation fractions for bottom hadrons in pp̄ collisions at s=1.96TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 77:7 (2008)

Authors:

T Aaltonen, J Adelman, T Akimoto, MG Albrow, BA González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, M Aoki, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzi-Bacchetta, P Azzurri, N Bacchetta, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, P Bednar, S Behari, G Bellettini, J Bellinger, A Belloni, D Benjamin, A Beretvas, J Beringer, T Berry, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, A Bolshov, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, M Campanelli, M Campbell, F Canelli, A Canepa, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, G Choudalakis, SH Chuang, K Chung, WH Chung, YS Chung, CI Ciobanu

Abstract:

This paper describes the first measurement of b-quark fragmentation fractions into bottom hadrons in Run II of the Tevatron Collider at Fermilab. The result is based on a 360pb-1 sample of data collected with the CDF II detector in pp̄ collisions at s=1.96TeV. Semileptonic decays of B̄0, B-, and B̄s0 mesons, as well as Λb0 baryons, are reconstructed. For an effective bottom hadron pT threshold of 7GeV/c, the fragmentation fractions are measured to be fu/fd=1.054±0.018(stat)-0.045+0.025(sys)±0. 058(B), fs/(fu+fd)=0.160±0.005(stat)-0.010+0.011(sys)-0.034+0.057(B), and fΛb/(fu+fd)=0.281±0.012(stat)-0.056+0.058(sys)-0.087+0.128(B), where the uncertainty B is due to uncertainties on measured branching ratios. The value of fs/(fu+fd) agrees within one standard deviation with previous CDF measurements and the world average of this quantity, which is dominated by LEP measurements. However, the ratio fΛb/(fu+fd) is approximately twice the value previously measured at LEP. The approximately 2σ discrepancy is examined in terms of kinematic differences between the two production environments. © 2008 The American Physical Society.
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A ring trap for ultracold atoms in an RF-dressed state

New Journal of Physics 10 (2008)

Authors:

WH Heathcote, E Nugent, BT Sheard, CJ Foot

Abstract:

We combine an RF-dressed magnetic trap with an optical potential to produce a toroidal trapping potential for ultracold 87Rb atoms. We load atoms into this ring trap from a conventional magnetic trap and compare the measured oscillation frequencies with theoretical predictions. This method of making a toroidal trap gives a high degree of flexibility such as a tuneable radius and variable transverse oscillation frequency. The ring trap is ideal for the creation of a multiply connected Bose-Einstein condensate (BEC) and the study of persistent flow and we propose a scheme for introducing a flow of the atoms around the ring. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.
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Search for Heavy, Long-Lived Neutralinos that Decay to Photons at CDF II Using Photon Timing

ArXiv 0804.1043 (2008)
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