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Measurement of cross sections for b jet production in events with a Z boson in pp̄ collisions at s=1.96TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 79:5 (2009)

Authors:

T Aaltonen, J Adelman, T Akimoto, BAL González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzurri, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, J Beringer, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, S Burke, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, C Calancha, M Campanelli, M Campbell, F Canelli, A Canepa, B Carls, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, V Cavaliere, 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, T Chwalek, CI Ciobanu, MA Ciocci, A Clark, D Clark

Abstract:

A measurement of the b jet production cross section is presented for events containing a Z boson produced in pp̄ collisions at s=1.96TeV, using data corresponding to an integrated luminosity of 2fb-1 collected by the CDF II detector at the Tevatron. Z bosons are selected in the electron and muon decay modes. Jets are considered with transverse energy ET>20GeV and pseudorapidity |η|<1.5 and are identified as b jets using a secondary vertex algorithm. The ratio of the integrated Z+b jet cross section to the inclusive Z production cross section is measured to be 3.32±0.53(stat)±0.42(syst) ×10-3. This ratio is also measured differentially in jet ET, jet η, Z-boson transverse momentum, number of jets, and number of b jets. The predictions from leading-order Monte Carlo generators and next-to-leading-order QCD calculations are found to be consistent with the measurements within experimental and theoretical uncertainties. © 2009 The American Physical Society.
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Measurement of the tt̄ production cross section in 2fb-1 of pp̄ collisions at s=1.96TeV using lepton plus jets events with soft muon b tagging

Physical Review D - Particles, Fields, Gravitation and Cosmology 79:5 (2009)

Authors:

T Aaltonen, J Adelman, T Akimoto, B Álvarez González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzurri, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, J Beringer, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, S Burke, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, C Calancha, M Campanelli, M Campbell, F Canelli, A Canepa, B Carls, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, V Cavaliere, 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, T Chwalek, CI Ciobanu, MA Ciocci, A Clark, D Clark

Abstract:

We present a measurement of the tt̄ production cross section in pp̄ collisions at s=1.96TeV using events containing a high transverse momentum electron or muon, three or more jets, and missing transverse energy. Events consistent with tt̄ decay are found by identifying jets containing candidate heavy-flavor semileptonic decays to muons. The measurement uses a CDF run II data sample corresponding to 2fb-1 of integrated luminosity. Based on 248 candidate events with three or more jets and an expected background of 79.5±5.3 events, we measure a production cross section of 9.1±1.6pb. © 2009 The American Physical Society.
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Search for new physics in the μμ+e/μ+E T channel with a low-pT lepton threshold at the Collider Detector at Fermilab

Physical Review D - Particles, Fields, Gravitation and Cosmology 79:5 (2009)

Authors:

T Aaltonen, J Adelman, T Akimoto, MG Albrow, BA González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzurri, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, J Beringer, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, S Burke, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, C Calancha, M Campanelli, M Campbell, F Canelli, A Canepa, B Carls, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, V Cavaliere, 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, T Chwalek, CI Ciobanu, MA Ciocci, A Clark

Abstract:

A search for new physics using three-lepton (trilepton) data collected with the CDF II detector and corresponding to an integrated luminosity of 976 pb-1 is presented. The standard model predicts a low rate of trilepton events, which makes some supersymmetric processes, such as chargino-neutralino production, measurable in this channel. The μμ+ signature is investigated, where ℓ is an electron or a muon, with the additional requirement of large missing transverse energy. In this analysis, the lepton transverse momenta with respect to the beam direction (pT) are as low as 5GeV/c, a selection that improves the sensitivity to particles that are light as well as to ones that result in leptonically decaying tau leptons. At the same time, this low-pT selection presents additional challenges due to the non-negligible heavy-quark background at low lepton momenta. This background is measured with an innovative technique using experimental data. Several dimuon and trilepton control regions are investigated, and good agreement between experimental results and standard-model predictions is observed. In the signal region, we observe one three-muon event and expect 0.4±0.1μμ+ events from standard-model processes. © 2009 The American Physical Society.
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Study of D0→π-e+νe, D+→π0e+νe, D0→K-e+νe, and D+→K̄0e+νe in tagged decays of the ψ(3770) resonance

Physical Review D - Particles, Fields, Gravitation and Cosmology 79:5 (2009)

Authors:

JY Ge, DH Miller, V Pavlunin, B Sanghi, IPJ Shipsey, B Xin, GS Adams, D Hu, B Moziak, J Napolitano, KM Ecklund, Q He, J Insler, H Muramatsu, CS Park, EH Thorndike, F Yang, YS Gao, F Liu, M Artuso, S Blusk, S Khalil, J Li, R Mountain, K Randrianarivony, N Sultana, T Skwarnicki, S Stone, JC Wang, LM Zhang, G Bonvicini, D Cinabro, M Dubrovin, A Lincoln, P Naik, J Rademacker, DM Asner, KW Edwards, J Reed, RA Briere, G Tatishvili, H Vogel, PUE Onyisi, JL Rosner, JP Alexander, DG Cassel, JE Duboscq, R Ehrlich, L Fields, L Gibbons, R Gray, SW Gray, DL Hartill, BK Heltsley, D Hertz, JM Hunt, J Kandaswamy, DL Kreinick, VE Kuznetsov, J Ledoux, H Mahlke-Krüger, D Mohapatra, JR Patterson, D Peterson, D Riley, A Ryd, AJ Sadoff, X Shi, S Stroiney, WM Sun, T Wilksen, SB Athar, J Yelton, P Rubin, 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, P Zweber, S Dobbs, Z Metreveli, KK Seth, BJY Tan, A Tomaradze, J Libby, L Martin, A Powell

Abstract:

Using ψ(3770)→DD̄ events collected with the CLEO-c detector at the Cornell e+e- storage ring, tagged by fully reconstructing one D meson in a hadronic decay mode, we measure absolute branching fractions and differential decay rates for D0→π-e+νe, D+→π0e+νe, D0→K-e+νe, and D+→K̄0e+νe. The measured decay rates are used to study semileptonic form factors governing these transitions and to test unquenched Lattice QCD (LQCD) calculations. We average our results with previously published CLEO-c measurements of the same quantities using a neutrino reconstruction technique. Combining LQCD calculations of form factor absolute normalizations f+(0) and measurements of f+π(0)|Vcd| and f+K(0)|Vcs|, we find |Vcd|=0.222(8)(3)(23) and |Vcs|=1.018(10)(8)(106), where the uncertainties are statistical, experimental systematic, and from LQCD, respectively. © 2009 The American Physical Society.
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A study of bb̄ production in e+e- collisions at √ = 130-207 GeV

European Physical Journal C 60:1 (2009) 1-15

Authors:

J Abdallah, P Abreu, W Adam, P Adzic, T Albrecht, R Alemany-Fernandez, T Allmendinger, PP Allport, U Amaldi, N Amapane, S Amato, E Anashkin, A Andreazza, S Andringa, N Anjos, P Antilogus, WD Apel, Y Arnoud, S Ask, B Asman, JE Augustin, A Augustinus, P Baillon, A Ballestrero, P Bambade, R Barbier, D Bardin, GJ Barker, A Baroncelli, M Battaglia, M Baubillier, KH Becks, M Begalli, A Behrmann, E Ben-Haim, N Benekos, A Benvenuti, C Berat, M Berggren, D Bertrand, M Besancon, N Besson, D Bloch, M Blom, M Bluj, M Bonesini, M Boonekamp, PSL Booth, G Borisov, O Botner, B Bouquet, TJV Bowcock, I Boyko, M Bracko, R Brenner, E Brodet, P Bruckman, JM Brunet, B Buschbeck, P Buschmann, M Calvi, T Camporesi, V Canale, F Carena, N Castro, F Cavallo, M Chapkin, P Charpentier, P Checchia, R Chierici, P Chliapnikov, J Chudoba, SU Chung, K Cieslik, P Collins, R Contri, G Cosme, F Cossutti, MJ Costa, D Crennell, J Cuevas, J D'Hondt, T Da Silva, W Da Silva, G Della Ricca, A De Angelis, W De Boer, C De Clercq, B De Lotto, N De Maria, A De Min, L De Paula, L Di Ciaccio, A Di Simone, K Doroba, J Drees, G Eigen, T Ekelof, M Ellert, M Elsing

Abstract:

Measurements are presented of R b, the ratio of the cross-section to the cross-section in e+e- collisions, and the forward-backward asymmetry A FBb at twelve energy points in the range sqrt{s}=130-207 GeV. These results are found to be consistent with the Standard Model expectations. The measurements are used to set limits on new physics scenarios involving contact interactions. © 2009 Springer-Verlag / Società Italiana di Fisica.
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