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Measurement of the tt̄ production cross section with an in situ calibration of b-jet identification efficiency

Physical Review D - Particles, Fields, Gravitation and Cosmology 83:7 (2011)

Authors:

T Aaltonen, B Álvarez González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, JA Appel, A Apresyan, T Arisawa, A Artikov, J Asaadi, W Ashmanskas, B Auerbach, A Aurisano, F Azfar, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, P Barria, P Bartos, M Bauce, G Bauer, F Bedeschi, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, A Bhatti, M Binkley, D Bisello, I Bizjak, KR Bland, C Blocker, B Blumenfeld, A Bocci, A Bodek, D Bortoletto, J Boudreau, A Boveia, B Brau, L Brigliadori, A Brisuda, C Bromberg, E Brucken, M Bucciantonio, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, S Cabrera, C Calancha, S Camarda, 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, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, WH Chung, YS Chung, CI Ciobanu, MA Ciocci, A Clark, D Clark, G Compostella, ME Convery, J Conway, M Corbo, M Cordelli, CA Cox, DJ Cox, F Crescioli

Abstract:

A measurement of the top-quark pair-production cross section in pp̄ collisions at √s=1.96TeV using data corresponding to an integrated luminosity of 1.12fb-1 collected with the Collider Detector at Fermilab is presented. Decays of top-quark pairs into the final states eν+ jets and μν+ jets are selected, and the cross section and the b-jet identification efficiency are determined using a new measurement technique which requires agreement between the measured cross sections with exactly one and with multiple identified b quarks from the top-quark decays. Assuming a top-quark mass of 175GeV/c2, a cross section of 8.5±0.6(stat)±0. 7(syst)pb is measured. © 2011 American Physical Society.
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Search for supersymmetry in pp collisions at 7 TeV in events with jets and missing transverse energy

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 698:3 (2011) 196-218

Authors:

V Khachatryan, AM Sirunyan, A Tumasyan, W Adam, T Bergauer, M Dragicevic, J Erö, C Fabjan, M Friedl, R Frühwirth, VM Ghete, J Hammer, S Hänsel, C Hartl, M Hoch, N Hörmann, J Hrubec, M Jeitler, G Kasieczka, W Kiesenhofer, M Krammer, D Liko, I Mikulec, M Pernicka, H Rohringer, R Schöfbeck, J Strauss, A Taurok, F Teischinger, P Wagner, W Waltenberger, G Walzel, E Widl, CE Wulz, V Mossolov, N Shumeiko, J Suarez Gonzalez, L Benucci, K Cerny, EA De Wolf, X Janssen, T Maes, L Mucibello, S Ochesanu, B Roland, R Rougny, M Selvaggi, H Van Haevermaet, P Van Mechelen, N Van Remortel

Abstract:

A search for supersymmetry with R-parity conservation in proton-proton collisions at a centre-of-mass energy of 7 TeV is presented. The data correspond to an integrated luminosity of 35 pb-1 collected by the CMS experiment at the LHC. The search is performed in events with jets and significant missing transverse energy, characteristic of the decays of heavy, pair-produced squarks and gluinos. The primary background, from standard model multijet production, is reduced by several orders of magnitude to a negligible level by the application of a set of robust kinematic requirements. With this selection, the data are consistent with the standard model backgrounds, namely tt, W. +. jet and Z. +. jet production, which are estimated from data control samples. Limits are set on the parameters of the constrained minimal supersymmetric extension of the standard model. These limits extend those set previously by experiments at the Tevatron and LEP colliders. © 2011 CMS Collaboration.
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DISPLAYING THE HETEROGENEITY OF THE SN 2002cx-LIKE SUBCLASS OF TYPE Ia SUPERNOVAE WITH OBSERVATIONS OF THE Pan-STARRS-1 DISCOVERED SN 2009ku**This Letter includes data gathered with the 6.5 m Magellan Telescopes located at the Las Campanas Observatory, Chile; the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the Nordic Optical Telescope, operated by Denmark, Finland, Iceland, Norway, and Sweden; the Liverpool Telescope operated by the Liverpool John Moores University with financial support from the UK Science and Technology Facilities Council on the island of La Palma in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias; and the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the National Science Foundation.

The Astrophysical Journal Letters American Astronomical Society 731:1 (2011) l11

Authors:

G Narayan, RJ Foley, E Berger, MT Botticella, R Chornock, ME Huber, A Rest, D Scolnic, S Smartt, S Valenti, AM Soderberg, WS Burgett, KC Chambers, HA Flewelling, G Gates, T Grav, N Kaiser, RP Kirshner, EA Magnier, JS Morgan, PA Price, AG Riess, CW Stubbs, WE Sweeney, JL Tonry, RJ Wainscoat, C Waters, WM Wood-Vasey
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Observing pulsars and fast transients with LOFAR

(2011)

Authors:

BW Stappers, JWT Hessels, A Alexov, K Anderson, T Coenen, T Hassall, A Karastergiou, VI Kondratiev, M Kramer, J van Leeuwen, JD Mol, A Noutsos, JW Romein, P Weltevrede, R Fender, RAMJ Wijers, L Bähren, ME Bell, J Broderick, EJ Daw, VS Dhillon, J Eislöffel, H Falcke, J Griessmeier, C Law, S Markoff, JCA Miller-Jones, B Scheers, H Spreeuw, J Swinbank, S ter Veen, MW Wise, O Wucknitz, P Zarka, J Anderson, A Asgekar, IM Avruch, R Beck, P Bennema, MJ Bentum, P Best, J Bregman, M Brentjens, RH van de Brink, PC Broekema, WN Brouw, M Brüggen, AG de Bruyn, HR Butcher, B Ciardi, J Conway, R-J Dettmar, A van Duin, J van Enst, M Garrett, M Gerbers, T Grit, A Gunst, MP van Haarlem, JP Hamaker, G Heald, M Hoeft, H Holties, A Horneffer, LVE Koopmans, G Kuper, M Loose, P Maat, D McKay-Bukowski, JP McKean, G Miley, R Morganti, R Nijboer, JE Noordam, M Norden, H Olofsson, M Pandey-Pommier, A Polatidis, W Reich, H Röttgering, A Schoenmakers, J Sluman, O Smirnov, M Steinmetz, CGM Sterks, M Tagger, Y Tang, R Vermeulen, N Vermaas, C Vogt, M de Vos, SJ Wijnholds, S Yatawatta, A Zensus
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Search for heavy bottomlike quarks decaying to an electron or muon and jets in pp collisions at √s = 1.96  TeV.

Phys Rev Lett 106:14 (2011) 141803

Authors:

T Aaltonen, B Álvarez González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, JA Appel, A Apresyan, T Arisawa, A Artikov, J Asaadi, W Ashmanskas, B Auerbach, A Aurisano, F Azfar, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, P Barria, P Bartos, M Bauce, G Bauer, F Bedeschi, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, A Bhatti, M Binkley, D Bisello, I Bizjak, KR Bland, B Blumenfeld, A Bocci, A Bodek, D Bortoletto, J Boudreau, A Boveia, B Brau, L Brigliadori, A Brisuda, C Bromberg, E Brucken, M Bucciantonio, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, C Calancha, S Camarda, 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, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, WH Chung, YS Chung, CI Ciobanu, MA Ciocci, A Clark, G Compostella, ME Convery, J Conway, M Corbo, M Cordelli, CA Cox, DJ Cox, F Crescioli, C Cuenca Almenar, J Cuevas, R Culbertson, D Dagenhart, N d'Ascenzo, M Datta, P de Barbaro, S De Cecco, G De Lorenzo, M Dell'Orso, C Deluca, L Demortier, J Deng, M Deninno, F Devoto, M d'Errico, A Di Canto, B Di Ruzza, JR Dittmann, M D'Onofrio, S Donati, P Dong, M Dorigo, T Dorigo, K Ebina, A Elagin, A Eppig, R Erbacher, D Errede, S Errede, N Ershaidat, R Eusebi, HC Fang, S Farrington, M Feindt, JP Fernandez, C Ferrazza, R Field, G Flanagan, R Forrest, MJ Frank, M Franklin, JC Freeman, Y Funakoshi, I Furic, M Gallinaro, J Galyardt, JE Garcia, AF Garfinkel, P Garosi, H Gerberich, E Gerchtein, S Giagu, V Giakoumopoulou, P Giannetti, K Gibson, CM Ginsburg, N Giokaris, P Giromini, M Giunta, G Giurgiu, V Glagolev, D Glenzinski, M Gold, D Goldin, 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, RC Group, J Guimaraes da Costa, Z Gunay-Unalan, C Haber, SR Hahn, E Halkiadakis, A Hamaguchi, JY Han, F Happacher, K Hara, D Hare, M Hare, RF Harr, K Hatakeyama, C Hays, M Heck, J Heinrich, M Herndon, S Hewamanage, D Hidas, A Hocker, W Hopkins, D Horn, S Hou, RE Hughes, M Hurwitz, U Husemann, N Hussain, M Hussein, J Huston, 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, TR Junk, T Kamon, PE Karchin, Y Kato, W Ketchum, J Keung, V Khotilovich, B Kilminster, DH Kim, HS Kim, HW Kim, JE Kim, MJ Kim, SB Kim, SH Kim, YK Kim, N Kimura, M Kirby, S Klimenko, K Kondo, DJ Kong, J Konigsberg, AV Kotwal, M Kreps, J Kroll, D Krop, N Krumnack, M Kruse, V Krutelyov, T Kuhr, 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, JS Lee, SW Lee, S Leo, S Leone, JD Lewis, C-J Lin, J Linacre, M Lindgren, E Lipeles, A Lister, DO Litvintsev, C Liu, Q Liu, T Liu, S Lockwitz, NS Lockyer, A Loginov, D Lucchesi, J Lueck, P Lujan, P Lukens, G Lungu, J Lys, R Lysak, R Madrak, K Maeshima, K Makhoul, P Maksimovic, S Malik, G Manca, A Manousakis-Katsikakis, F Margaroli, C Marino, M Martínez, R Martínez-Ballarín, P Mastrandrea, M Mathis, ME Mattson, P Mazzanti, KS McFarland, P McIntyre, R McNulty, A Mehta, P Mehtala, A Menzione, C Mesropian, T Miao, D Mietlicki, A Mitra, H Miyake, S Moed, N Moggi, MN Mondragon, CS Moon, R Moore, MJ Morello, J Morlock, P Movilla Fernandez, A Mukherjee, Th Muller, P Murat, M Mussini, J Nachtman, Y Nagai, J Naganoma, I Nakano, A Napier, J Nett, C Neu, MS Neubauer, J Nielsen, L Nodulman, O Norniella, E Nurse, L Oakes, SH Oh, YD Oh, I Oksuzian, T Okusawa, R Orava, L Ortolan, S Pagan Griso, C Pagliarone, E Palencia, V Papadimitriou, AA Paramonov, J Patrick, G Pauletta, M Paulini, C Paus, DE Pellett, A Penzo, TJ Phillips, G Piacentino, E Pianori, J Pilot, K Pitts, C Plager, L Pondrom, K Potamianos, O Poukhov, F Prokoshin, A Pronko, F Ptohos, E Pueschel, G Punzi, J Pursley, A Rahaman, V Ramakrishnan, N Ranjan, I Redondo, P Renton, M Rescigno, F Rimondi, L Ristori, A Robson, T Rodrigo, T Rodriguez, E Rogers, S Rolli, R Roser, M Rossi, F Rubbo, F Ruffini, A Ruiz, J Russ, V Rusu, A Safonov, WK Sakumoto, Y Sakurai, L Santi, L Sartori, K Sato, V Saveliev, A Savoy-Navarro, P Schlabach, A Schmidt, EE Schmidt, MP Schmidt, M Schmitt, T Schwarz, L Scodellaro, A Scribano, F Scuri, A Sedov, S Seidel, Y Seiya, A Semenov, F Sforza, A Sfyrla, SZ Shalhout, T Shears, PF Shepard, M Shimojima, S Shiraishi, M Shochet, I Shreyber, A Simonenko, P Sinervo, A Sissakian, K Sliwa, JR Smith, FD Snider, A Soha, S Somalwar, V Sorin, P Squillacioti, M Stancari, M Stanitzki, R St Denis, B Stelzer, O Stelzer-Chilton, D Stentz, J Strologas, GL Strycker, Y Sudo, A Sukhanov, I Suslov, K Takemasa, Y Takeuchi, J Tang, M Tecchio, PK Teng, J Thom, J Thome, GA Thompson, E Thomson, P Ttito-Guzmán, S Tkaczyk, D Toback, S Tokar, K Tollefson, T Tomura, D Tonelli, S Torre, D Torretta, P Totaro, M Trovato, Y Tu, F Ukegawa, S Uozumi, A Varganov, F Vázquez, G Velev, C Vellidis, M Vidal, I Vila, R Vilar, J Vizán, M Vogel, G Volpi, P Wagner, RL Wagner, T Wakisaka, R Wallny, SM Wang, A Warburton, D Waters, M Weinberger, WC Wester, B Whitehouse, D Whiteson, AB Wicklund, E Wicklund, S Wilbur, F Wick, HH Williams, JS Wilson, P Wilson, BL Winer, P Wittich, S Wolbers, H Wolfe, T Wright, X Wu, Z Wu, K Yamamoto, J Yamaoka, T Yang, UK Yang, YC Yang, W-M Yao, GP Yeh, K Yi, J Yoh, K Yorita, T Yoshida, GB Yu, I Yu, SS Yu, JC Yun, A Zanetti, Y Zeng, S Zucchelli, CDF Collaboration

Abstract:

We report the most sensitive direct search for pair production of fourth-generation bottomlike chiral quarks (b') each decaying promptly to tW. We search for an excess of events with an electron or muon, at least five jets (one identified as due to a b or c quark), and an imbalance of transverse momentum by using data from pp collisions collected by the CDF II detector at Fermilab with an integrated luminosity of 4.8  fb(-1). We observe events consistent with background expectation, calculate upper limits on the b' pair-production cross section (σ(bb')) ≲30  fb for m(b') > 375  GeV/c2), and exclude m(b') < 372  GeV/c2 at 95% confidence level assuming a 100% branching ratio of b' to tW.
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