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Search for supersymmetry in pp collisions at s=1.96TeV using the trilepton signature for chargino-neutralino production

Physical Review Letters 101:25 (2008)

Authors:

T Aaltonen, J Adelman, T Akimoto, MG Albrow, 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, P Bednar, 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, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, C Calancha, 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, 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, CI Ciobanu, MA Ciocci, A Clark, D Clark, G Compostella

Abstract:

We use the three lepton and missing energy trilepton signature to search for chargino-neutralino production with 2.0fb-1 of integrated luminosity collected by the CDF II experiment at the Tevatron pp collider. We expect an excess of approximately 11 supersymmetric events for a choice of parameters of the mSUGRA model, but our observation of 7 events is consistent with the standard model expectation of 6.4 events. We constrain the mSUGRA model of supersymmetry and rule out chargino masses up to 145GeV/c2 for a specific choice of parameters. © 2008 The American Physical Society.
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Search for the Higgs Boson Produced in Association with Z→ℓ+ℓ- in pp̄ Collisions at s=1.96TeV

Physical Review Letters 101:25 (2008)

Authors:

T Aaltonen, J Adelman, T Akimoto, MG Albrow, 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, P Bednar, 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, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, C Calancha, 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, 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, CI Ciobanu, MA Ciocci, A Clark, D Clark, G Compostella

Abstract:

We present a search for the Higgs boson in the process qq̄→ ZH→ℓ+ℓ-bb̄. The analysis uses an integrated luminosity of 1fb-1 of pp̄ collisions produced at s=1.96TeV and accumulated by the upgraded Collider Detector at Fermilab (CDF II). We employ artificial neural networks both to correct jets mismeasured in the calorimeter and to distinguish the signal kinematic distributions from those of the background. We see no evidence for Higgs boson production, and set 95% C.L. upper limits on σZHB(H→bb̄), ranging from 1.5 to 1.2 pb for a Higgs boson mass (mH) of 110 to 150GeV/c2. © 2008 The American Physical Society.
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First measurement of the fraction of top-quark pair production through gluon-gluon fusion

Physical Review D - Particles, Fields, Gravitation and Cosmology 78:11 (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 first measurement of σ(gg→tt̄)/ σ(pp̄→tt̄). We use 0.96fb-1 of s=1.96TeV pp̄ collision data recorded with the CDF II detector at Fermilab. Using charged particles with low transverse momentum in tt̄ events, we find σ(gg→ tt̄)/σ(pp̄→tt̄)=0.07±0.14(stat)±0. 07(syst), corresponding to a 95% confidence level upper limit of 0.33, in agreement with the standard model next-to-leading-order prediction of 0.15±0.05. © 2008 The American Physical Society.
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The LHCb detector at the LHC

Journal of Instrumentation 3:8 (2008)

Authors:

A Augusto Alves, LM Andrade Filho, AF Barbosa, I Bediaga, G Cernicchiaro, G Guerrer, HP Lima, AA Machado, J Magnin, F Manijo, JM De Miranda, A Reis, A Santos, A Toledo, K Akiba, S Amato, B De Paula, L De Paula, T Da Silva, M Gandelman, JH Lopes, B Maréchal, D Moraes, E Polycarpo, F Rodrigues, J Ballansat, Y Bastían, D Boget, I De Bonis, V Coco, PY David, D Decamp, P Delebecque, C Drancourt, N Dumont-Dayot, C Girard, B Lieunard, MN Minard, B Pietrzyk, T Rambure, G Rospabe, S T'Jampens, Z Ajaltouni, G Bohner, R Bonnefoy, D Borras, C Carloganu, H Chanal, E Conte, R Cornat, M Crouau, E Delage, O Deschamps, P Henrard, P Jacquet, C Lacan, J Laubser, J Lecoq, R Lefèvre, M Magne, M Martemiyanov, ML Mercier, S Monteil, V Niess, P Perret, G Reinmuth, A Robert, S Suchorski, K Arnaud, E Aslanides, J Babel, C Benchouk, JP Cachemiche, J Cogan, F Derue, B Dinkespiler, PY Duval, V Garonne, S Favard, R Le Gac, F Leon, O Leroy, PL Liotard, F Marin, M Menouni, P Ollive, S Poss, A Roche, M Sapunov, L Tocco, B Viaud, A Tsaregorodtsev, Y Amhis, G Barrand, S Barsuk, C Beigbeder, R Beneyton, D Breton, O Callot, D Charlet

Abstract:

Large detector systems for particle and astroparticle physics; Particle tracking detectors; Gaseous detectors; Calorimeters; Cherenkov detectors; Particle identification methods; Photon detectors for UV. visible and IR photons; Detector alignment and calibration methods; Detector cooling and thermo-stabilization; Detector design and construction technologies and materials. The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems. as established by test beam measurements and simulation studies. is described. © 2008 IOP Publishing Ltd and SISSA.
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Two-photon widths of the χcJ states of charmonium

Physical Review D - Particles, Fields, Gravitation and Cosmology 78:9 (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, P Naik, J Rademacker, DM Asner, KW Edwards, J Reed, RA Briere, T Ferguson, G Tatishvili, H Vogel, ME Watkins, JL Rosner, JP Alexander, DG Cassel, JE Duboscq, R Ehrlich, L Fields, RS Galik, L Gibbons, R Gray, SW Gray, DL Hartill, D Hertz, JM Hunt, J Kandaswamy, DL Kreinick, VE Kuznetsov, J Ledoux, 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

Abstract:

Using a data sample of 24.5×106 ψ(2S) the reactions ψ(2S)→γχcJ, χcJ→γγ have been studied for the first time to determine the two-photon widths of the χcJ states of charmonium in their decay into two photons. The measured quantities are B(ψ(2S)→γχc0)×B(χc0→γγ)=(2. 17±0.32±0.10)×10-5 and B(ψ(2S)→γχc2) ×B(χc2→γγ)=(2.68±0.28±0.15)×10-5. Using values for B(ψ(2S)→γχc0,c2) and Γ(χc0,c2) from the literature the two-photon widths are derived to be Γγ γ(χc0)=(2.36±0.35±0.22)keV, Γγγ(χ c2)=(0.66±0.07±0.06)keV, and R≡Γγγ(χ c2)/Γγγ(χc0)=0.278±0.050±0.036. The importance of the measurement of R is emphasized. For the forbidden transition, χc1→γγ, an upper limit of Γγγ(χc1) <0.03keV is established. © 2008 The American Physical Society.
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