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Search for gluino-mediated bottom squark production in pp̄ collisions at s=1.96TeV

Physical Review Letters 102:22 (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, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, P Barria, 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 report on a search for the supersymmetric partner of the bottom quark produced from gluino decays in data from 2.5fb-1 of integrated luminosity collected by the Collider Detector at Fermilab at s=1.96TeV. Candidate events are selected requiring two or more jets and large missing transverse energy. At least two of the jets are required to be tagged as originating from a b quark to enhance the sensitivity. The results are in good agreement with the prediction of the standard model processes, giving no evidence for gluino decay to bottom squarks. This result constrains the gluino-pair-production cross section to be less than 40 fb at 95% credibility level for a gluino mass of 350GeV/c2. © 2009 The American Physical Society.
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First LHC beam induced tracks reconstructed in the LHCb VELO

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 604:1-2 (2009) 1-4

Authors:

C Parkes, S Borghi, A Bates, L Eklund, M Gersabeck, F Marinho, B Rakotomiaramanana, E Rodrigues, T Szumlak, A Affolder, T Bowcock, G Casse, S Donleavy, K Hennessy, T Huse, D Hutchcroft, J Mylroie-Smith, A Noor, G Patel, K Rinnert, NA Smith, T Shears, M Tobin, M John, A Bay, R Frei, G Haefeli, A Keune, J Anderson, R McNulty, S Traynor, S Basiladze, A Leflat, M Artuso, A Borgia, G Lefeuvre, R Mountain, J Wang, K Akiba, M van Beuzekom, E Jans, T Ketel, I Mous, A Papadelis, A Van Lysebetten, B Verlaat, H de Vries, O Behrendt, J Buytaert, S de Capua, P Collins, M Ferro-Luzzi

Abstract:

The Vertex Locator of the LHCb experiment has been used to fully reconstruct beam induced tracks at the LHC. A beam of protons was collided with a beam absorber during the LHC synchronisation test of the anti-clockwise beam on the weekend 22nd-24th August 2008. The resulting particles have been observed by the Vertex Locator. The LHCb Vertex Locator is a silicon micro-strip detector containing 21 planes of modules. Tracks were observed passing through up to 19 modules (38 silicon sensors). A total of over 700 tracks were reconstructed, and are being used to study the calibration and alignment of the detector. © 2009 Elsevier B.V. All rights reserved.
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Search for new particles decaying into dijets in proton-antiproton collisions at s=1.96TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 79:11 (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 search for new particles which produce narrow two-jet (dijet) resonances using proton-antiproton collision data corresponding to an integrated luminosity of 1.13fb-1 collected with the CDFA II detector. The measured dijet mass spectrum is found to be consistent with next-to-leading-order perturbative QCD predictions, and no significant evidence of new particles is found. We set upper limits at the 95% confidence level on cross sections times the branching fraction for the production of new particles decaying into dijets with both jets having a rapidity magnitude |y| <1. These limits are used to determine the mass exclusions for the excited quark, axigluon, flavor-universal coloron, E6 diquark, color-octet techni-ρ, W′, and Z′. © 2009 The American Physical Society.
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Search for the decays B_{(s)};{0} --> e;{+} micro;{-} and B_{(s)};{0} --> e;{+} e;{-} in CDF run II.

Phys Rev Lett 102:20 (2009) 201801

Authors:

T Aaltonen, J Adelman, T Akimoto, B Alvarez 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, P-H 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, G Compostella, ME Convery, J Conway, M Cordelli, G Cortiana, CA Cox, DJ Cox, F Crescioli, C Cuenca Almenar, J Cuevas, R Culbertson, JC Cully, D Dagenhart, M Datta, T Davies, P de Barbaro, S De Cecco, A Deisher, G De Lorenzo, M Dell'orso, C Deluca, L Demortier, J Deng, M Deninno, PF Derwent, GP di Giovanni, C Dionisi, B Di Ruzza, JR Dittmann, M D'Onofrio, S Donati, P Dong, J Donini, T Dorigo, S Dube, J Efron, A Elagin, R Erbacher, D Errede, S Errede, R Eusebi, HC Fang, S Farrington, WT Fedorko, RG Feild, M Feindt, JP Fernandez, C Ferrazza, R Field, G Flanagan, R Forrest, MJ Frank, M Franklin, JC Freeman, I Furic, M Gallinaro, J Galyardt, F Garberson, JE Garcia, AF Garfinkel, K Genser, H Gerberich, D Gerdes, A Gessler, S Giagu, V Giakoumopoulou, P Giannetti, K Gibson, JL Gimmell, CM Ginsburg, N Giokaris, M Giordani, P Giromini, M Giunta, G Giurgiu, V Glagolev, D Glenzinski, M Gold, N Goldschmidt, A Golossanov, G Gomez, G Gomez-Ceballos, M Goncharov, O González, I Gorelov, AT Goshaw, K Goulianos, A Gresele, S Grinstein, C Grosso-Pilcher, U Grundler, J Guimaraes da Costa, Z Gunay-Unalan, C Haber, K Hahn, SR Hahn, E Halkiadakis, B-Y Han, JY Han, F Happacher, K Hara, D Hare, M Hare, S Harper, RF Harr, RM Harris, M Hartz, K Hatakeyama, C Hays, M Heck, A Heijboer, J Heinrich, C Henderson, M Herndon, J Heuser, S Hewamanage, D Hidas, CS Hill, D Hirschbuehl, A Hocker, S Hou, M Houlden, S-C Hsu, BT Huffman, RE Hughes, U Husemann, M Hussein, J Huston, J Incandela, G Introzzi, M Iori, A Ivanov, E James, D Jang, B Jayatilaka, EJ Jeon, MK Jha, S Jindariani, W Johnson, M Jones, KK Joo, SY Jun, JE Jung, TR Junk, T Kamon, D Kar, PE Karchin, Y Kato, R Kephart, J Keung, V Khotilovich, B Kilminster, DH Kim, HS Kim, HW Kim, JE Kim, MJ Kim, SB Kim, SH Kim, YK Kim, N Kimura, L Kirsch, S Klimenko, B Knuteson, BR Ko, K Kondo, DJ Kong, J Konigsberg, A Korytov, AV Kotwal, M Kreps, J Kroll, D Krop, N Krumnack, M Kruse, V Krutelyov, T Kubo, T Kuhr, NP Kulkarni, M Kurata, S Kwang, AT Laasanen, S Lami, S Lammel, M Lancaster, RL Lander, K Lannon, A Lath, G Latino, I Lazzizzera, T Lecompte, E Lee, HS Lee, SW Lee, S Leone, JD Lewis, C-S Lin, J Linacre, M Lindgren, E Lipeles, A Lister, DO Litvintsev, C Liu, T Liu, NS Lockyer, A Loginov, M Loreti, L Lovas, D Lucchesi, C Luci, J Lueck, P Lujan, P Lukens, G Lungu, L Lyons, J Lys, R Lysak, D Macqueen, R Madrak, K Maeshima, K Makhoul, T Maki, P Maksimovic, S Malde, S Malik, G Manca, A Manousakis-Katsikakis, F Margaroli, C Marino, CP Marino, A Martin, V Martin, M Martínez, R Martínez-Ballarín, T Maruyama, P Mastrandrea, T Masubuchi, M Mathis, ME Mattson, P Mazzanti, KS McFarland, P McIntyre, R McNulty, A Mehta, P Mehtala, A Menzione, P Merkel, C Mesropian, T Miao, N Miladinovic, R Miller, C Mills, M Milnik, A Mitra, G Mitselmakher, H Miyake, N Moggi, CS Moon, R Moore, MJ Morello, J Morlock, P Movilla Fernandez, J Mülmenstädt, A Mukherjee, Th Muller, R Mumford, P Murat, M Mussini, J Nachtman, Y Nagai, A Nagano, J Naganoma, K Nakamura, I Nakano, A Napier, V Necula, J Nett, C Neu, MS Neubauer, S Neubauer, J Nielsen, L Nodulman, M Norman, O Norniella, E Nurse, L Oakes, SH Oh, YD Oh, I Oksuzian, T Okusawa, R Orava, K Osterberg, S Pagan Griso, E Palencia, V Papadimitriou, A Papaikonomou, AA Paramonov, B Parks, S Pashapour, J Patrick, G Pauletta, M Paulini, C Paus, T Peiffer, DE Pellett, A Penzo, TJ Phillips, G Piacentino, E Pianori, L Pinera, K Pitts, C Plager, L Pondrom, O Poukhov, N Pounder, F Prakoshyn, A Pronko, J Proudfoot, F Ptohos, E Pueschel, G Punzi, J Pursley, J Rademacker, A Rahaman, V Ramakrishnan, N Ranjan, I Redondo, P Renton, M Renz, M Rescigno, S Richter, F Rimondi, L Ristori, A Robson, T Rodrigo, T Rodriguez, E Rogers, S Rolli, R Roser, M Rossi, R Rossin, P Roy, A Ruiz, J Russ, V Rusu, B Rutherford, H Saarikko, A Safonov, WK Sakumoto, O Saltó, L Santi, S Sarkar, L Sartori, K Sato, A Savoy-Navarro, P Schlabach, A Schmidt, EE Schmidt, MA Schmidt, MP Schmidt, M Schmitt, T Schwarz, L Scodellaro, A Scribano, F Scuri, A Sedov, S Seidel, Y Seiya, A Semenov, L Sexton-Kennedy, F Sforza, A Sfyrla, SZ Shalhout, T Shears, PF Shepard, M Shimojima, S Shiraishi, M Shochet, Y Shon, I Shreyber, A Sidoti, P Sinervo, A Sisakyan, AJ Slaughter, J Slaunwhite, K Sliwa, JR Smith, FD Snider, R Snihur, A Soha, S Somalwar, V Sorin, J Spalding, T Spreitzer, P Squillacioti, M Stanitzki, R St Denis, B Stelzer, O Stelzer-Chilton, D Stentz, J Strologas, GL Strycker, D Stuart, JS Suh, A Sukhanov, I Suslov, T Suzuki, A Taffard, R Takashima, Y Takeuchi, R Tanaka, M Tecchio, PK Teng, K Terashi, J Thom, AS Thompson, GA Thompson, E Thomson, P Tipton, P Ttito-Guzmán, S Tkaczyk, D Toback, S Tokar, K Tollefson, T Tomura, D Tonelli, S Torre, D Torretta, P Totaro, S Tourneur, M Trovato, S-Y Tsai, Y Tu, N Turini, F Ukegawa, S Vallecorsa, N van Remortel, A Varganov, E Vataga, F Vázquez, G Velev, C Vellidis, M Vidal, R Vidal, I Vila, R Vilar, T Vine, M Vogel, I Volobouev, G Volpi, P Wagner, RG Wagner, RL Wagner, W Wagner, J Wagner-Kuhr, T Wakisaka, R Wallny, SM Wang, A Warburton, D Waters, M Weinberger, J Weinelt, H Wenzel, WC Wester, B Whitehouse, D Whiteson, AB Wicklund, E Wicklund, S Wilbur, G Williams, HH Williams, P Wilson, BL Winer, P Wittich, S Wolbers, C Wolfe, T Wright, X Wu, F Würthwein, S Xie, A Yagil, K Yamamoto, J Yamaoka, UK Yang, YC Yang, WM Yao, GP Yeh, J Yoh, K Yorita, T Yoshida, GB Yu, I Yu, SS Yu, JC Yun, L Zanello, A Zanetti, X Zhang, Y Zheng, S Zucchelli, CDF Collaboration

Abstract:

We report results from a search for the lepton flavor violating decays B_{s};{0} --> e;{+} micro;{-} and B;{0} --> e;{+} micro;{-}, and the flavor-changing neutral-current decays B_{s};{0} --> e;{+} e;{-} and B;{0} --> e;{+} e;{-}. The analysis uses data corresponding to 2 fb;{-1} of integrated luminosity of pp[over ] collisions at sqrt[s] = 1.96 TeV collected with the upgraded Collider Detector (CDF II) at the Fermilab Tevatron. The observed number of B0 and B_{s};{0} candidates is consistent with background expectations. The resulting Bayesian upper limits on the branching ratios at 90% credibility level are B(B_{s};{0} --> e;{+} micro;{-}) < 2.0 x 10;{-7}, B(B;{0} --> e;{+} micro;{-}) < 6.4 x 10;{-8}, B(B_{s};{0} --> e;{+} e;{-}) < 2.8 x 10;{-7}, and B(B;{0} --> e;{+} e;{-}) < 8.3 x 10;{-8}. From the limits on B(B_{(s)};{0} --> e;{+} micro;{-}), the following lower bounds on the Pati-Salam leptoquark masses are also derived: M_{LQ}(B_{s};{0} --> e;{+} micro;{-}) > 47.8 TeV/c;{2}, and M_{LQ}(B;{0} --> e;{+} micro;{-}) > 59.3 TeV / c;{2}, at 90% credibility level.
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Performance of the LHCb RICH photo-detectors and readout in a system test using charged particles from a 25 ns-structured beam

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 603:3 (2009) 287-293

Authors:

M Adinolfi, E Albrecht, C D'Ambrosio, T Gys, J Morant, D Piedigrossi, M Patel, K Wyllie, M Ameri, F Fontanelli, G Mini, M Sannino, C Arnaboldi, TF Bellunato, E Fanchini, DL Perego, G Pessina, C Barham, C Buszello, J Dickens, V Gibson, C Jones, U Kerzel, G Rogers, H Skottowe, S Wotton, T Blake, C Eames, R Plackett, S Brisbane, N Harnew, J Libby, A Powell, P Sullivan, S Topp-Jorgensen, S Easo, A Papanestis, Z Zhang, S Eisenhardt, F Muheim, N Styles

Abstract:

The LHCb experiment at the CERN Large Hadron Collider (LHC) utilises two Ring Imaging CHerenkov (RICH) detectors for particle identification. To verify that the RICH assembly will perform as expected prior to installation, an array of 48 production Hybrid Photon Detectors and their readout have been tested under realistic running conditions in a 25 ns-structured charged particle beam provided by the SPS facility at CERN. This system test is an important milestone in the overall commissioning of the LHCb detector and demonstrates that all aspects meet the stringent physics requirements of the LHCb experiment. © 2009 Elsevier B.V.
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