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Search for high mass dilepton resonances in pp collisions at 鈭歴=7 TeV with the ATLAS experiment

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 700:3-4 (2011) 163-180

Authors:

G Aad, B Abbott, J Abdallah, AA Abdelalim, A Abdesselam, O Abdinov, B Abi, M Abolins, H Abramowicz, H Abreu, E Acerbi, BS Acharya, DL Adams, TN Addy, J Adelman, M Aderholz, S Adomeit, P Adragna, T Adye, S Aefsky, JA Aguilar-Saavedra, M Aharrouche, SP Ahlen, F Ahles, A Ahmad, M Ahsan, G Aielli, T Akdogan, TPA 脜kesson, G Akimoto, AV Akimov, A Akiyama, MS Alam, MA Alam, S Albrand, M Aleksa, IN Aleksandrov, F Alessandria, C Alexa, G Alexander, G Alexandre, T Alexopoulos, M Alhroob, M Aliev, G Alimonti, J Alison, M Aliyev, PP Allport, SE Allwood-Spiers, J Almond, A Aloisio, R Alon, A Alonso, MG Alviggi, K Amako, P Amaral, C Amelung, VV Ammosov, A Amorim, G Amor贸s, N Amram, C Anastopoulos, T Andeen, CF Anders, KJ Anderson, A Andreazza, V Andrei, ML Andrieux, XS Anduaga, A Angerami, F Anghinolfi, N Anjos, A Annovi, A Antonaki, M Antonelli, S Antonelli, A Antonov, J Antos, F Anulli, S Aoun, L Aperio Bella, R Apolle, G Arabidze, I Aracena, Y Arai, ATH Arce, JP Archambault, S Arfaoui, JF Arguin, E Arik, M Arik, AJ Armbruster, O Arnaez, C Arnault, A Artamonov, G Artoni, D Arutinov, S Asai, R Asfandiyarov, S Ask

Abstract:

This Letter presents a search for high mass e+e- or 渭+渭- resonances in pp collisions at 鈭歴=7 TeV at the LHC. The data were recorded by the ATLAS experiment during 2010 and correspond to a total integrated luminosity of ~40 pb-1. No statistically significant excess above the Standard Model expectation is observed in the search region of dilepton invariant mass above 110 GeV. Upper limits at the 95% confidence level are set on the cross section times branching ratio of Z' resonances decaying to dielectrons and dimuons as a function of the resonance mass. A lower mass limit of 1.048 TeV on the Sequential Standard Model Z' boson is derived, as well as mass limits on Z* and E6-motivated Z' models. 漏 2011 CERN.

Evidence for a mass dependent forward-backward asymmetry in top quark pair production

Physical Review D - Particles, Fields, Gravitation and Cosmology 83:11 (2011)

Authors:

T Aaltonen, B 脕lvarez Gonz谩lez, 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

Abstract:

We present a new measurement of the inclusive forward-backward tt虅 production asymmetry and its rapidity and mass dependence. The measurements are performed with data corresponding to an integrated luminosity of 5.3fb -1 of pp虅 collisions at 鈭歴=1.96TeV, recorded with the CDF-II Detector at the Fermilab Tevatron. Significant inclusive asymmetries are observed in both the laboratory frame and the tt虅 rest frame, and in both cases are found to be consistent with CP conservation under interchange of t and t虅. In the tt虅 rest frame, the asymmetry is observed to increase with the tt虅 rapidity difference, 螖y, and with the invariant mass M tt虅 of the tt虅 system. Fully corrected parton-level asymmetries are derived in two regions of each variable, and the asymmetry is found to be most significant at large 螖y and Mtt虅. For Mtt虅?450GeV/c2, the parton-level asymmetry in the tt虅 rest frame is Att虅=0.475卤0.114 compared to a next-to-leading order QCD prediction of 0.088卤0.013. 漏 2011 American Physical Society.

The T2K Experiment

(2011)

Authors:

T2K Collaboration, K Abe, N Abgrall, H Aihara, Y Ajima, JB Albert, D Allan, P-A Amaudruz, C Andreopoulos, B Andrieu, MD Anerella, C Angelsen, S Aoki, O Araoka, J Argyriades, A Ariga, T Ariga, S Assylbekov, JPAM de Andr茅, D Autiero, A Badertscher, O Ballester, M Barbi, GJ Barker, P Baron, G Barr, L Bartoszek, M Batkiewicz, F Bay, S Bentham, V Berardi, BE Berger, H Berns, I Bertram, M Besnier, J Beucher, D Beznosko, S Bhadra, P Birney, D Bishop, E Blackmore, FDM Blaszczyk, J Blocki, A Blondel, A Bodek, C Bojechko, J Bouchez, T Boussuge, SB Boyd, M Boyer, N Braam, R Bradford, A Bravar, K Briggs, JD Brinson, C Bronner, DG Brook-Roberge, M Bryant, N Buchanan, H Budd, M Cadabeschi, RG Calland, D Calvet, J Caravaca Rodr铆guez, J Carroll, SL Cartwright, A Carver, R Castillo, MG Catanesi, C Cavata, A Cazes, A Cervera, JP Charrier, C Chavez, S Choi, S Chollet, G Christodoulou, P Colas, J Coleman, W Coleman, G Collazuol, K Connolly, P Cooke, A Curioni, A Dabrowska, I Danko, R Das, GS Davies, S Davis, M Day, X De La Broise, P de Perio, G De Rosa, T Dealtry, A Debraine, E Delagnes, A Delbart, C Densham, F Di Lodovico, S Di Luise, P Dinh Tran, J Dobson, J Doornbos, U Dore, O Drapier, F Druillole, F Dufour, J Dumarchez, T Durkin, S Dytman, M Dziewiecki, M Dziomba, B Ellison, S Emery, A Ereditato, JE Escallier, L Escudero, LS Esposito, W Faszer, M Fechner, A Ferrero, A Finch, C Fisher, M Fitton, R Flight, D Forbush, E Frank, K Fransham, Y Fujii, Y Fukuda, M Gallop, V Galymov, GL Ganetis, FC Gannaway, A Gaudin, J Gaweda, A Gendotti, M George, S Giffin, C Giganti, K Gilje, I Giomataris, J Giraud, AK Ghosh, T Golan, M Goldhaber, JJ Gomez-Cadenas, S Gomi, M Gonin, M Goyette, A Grant, N Grant, F Gra帽ena, S Greenwood, P Gumplinger, P Guzowski, MD Haigh, K Hamano, C Hansen, T Hara, PF Harrison, B Hartfiel, M Hartz, T Haruyama, R Hasanen, T Hasegawa, NC Hastings, S Hastings, A Hatzikoutelis, K Hayashi, Y Hayato, TDJ Haycock, C Hearty, RL Helmer, R Henderson, S Herlant, N Higashi, J Hignight, K Hiraide, E Hirose, J Holeczek, N Honkanen, S Horikawa, A Hyndman, AK Ichikawa, K Ieki, M Ieva, M Iida, M Ikeda, J Ilic, J Imber, T Ishida, C Ishihara, T Ishii, SJ Ives, M Iwasaki, K Iyogi, A Izmaylov, B Jamieson, RA Johnson, KK Joo, G Jover-Manas, CK Jung, H Kaji, T Kajita, H Kakuno, J Kameda, K Kaneyuki, D Karlen, K Kasami, V Kasey, I Kato, H Kawamuko, E Kearns, L Kellet, M Khabibullin, M Khaleeq, N Khan, A Khotjantsev, D Kielczewska, T Kikawa, JY Kim, S-B Kim, N Kimura, B Kirby, J Kisiel, P Kitching, T Kobayashi, G Kogan, S Koike, T Komorowski, A Konaka, LL Kormos, A Korzenev, K Koseki, Y Koshio, Y Kouzuma, K Kowalik, V Kravtsov, I Kreslo, W Kropp, H Kubo, J Kubota, Y Kudenko, N Kulkarni, L Kurchaninov, Y Kurimoto, R Kurjata, Y Kurosawa, T Kutter, J Lagoda, K Laihem, R Langstaff, M Laveder, TB Lawson, PT Le, A Le Coguie, M Le Ross, KP Lee, M Lenckowski, C Licciardi, IT Lim, T Lindner, RP Litchfield, A Longhin, GD Lopez, P Lu, L Ludovici, T Lux, M Macaire, L Magaletti, K Mahn, Y Makida, CJ Malafis, M Malek, S Manly, A Marchionni, C Mark, AD Marino, AJ Marone, J Marteau, JF Martin, T Maruyama, T Maryon, J Marzec, P Masliah, EL Mathie, C Matsumura, K Matsuoka, V Matveev, K Mavrokoridis, E Mazzucato, N McCauley, KS McFarland, C McGrew, T McLachlan, I Mercer, M Messina, W Metcalf, C Metelko, M Mezzetto, P Mijakowski, CA Miller, A Minamino, O Mineev, S Mine, RE Minvielle, G Mituka, M Miura, K Mizouchi, J-P Mols, L Monfregola, E Monmarthe, F Moreau, B Morgan, S Moriyama, D Morris, A Muir, A Murakami, JF Muratore, M Murdoch, S Murphy, J Myslik, G Nagashima, T Nakadaira, M Nakahata, T Nakamoto, K Nakamura, S Nakayama, T Nakaya, D Naples, B Nelson, TC Nicholls, K Nishikawa, H Nishino, K Nitta, F Nizery, JA Nowak, M Noy, Y Obayashi, T Ogitsu, H Ohhata, T Okamura, K Okumura, T Okusawa, C Ohlmann, K Olchanski, R Openshaw, SM Oser, M Otani, RA Owen, Y Oyama, T Ozaki, MY Pac, V Palladino, V Paolone, P Paul, D Payne, GF Pearce, C Pearson, JD Perkin, M Pfleger, F Pierre, D Pierrepont, P Plonski, P Poffenberger, E Poplawska, B Popov, M Posiadala, J-M Poutissou, R Poutissou, R Preece, P Przewlocki, W Qian, JL Raaf, E Radicioni, K Ramos, P Ratoff, TM Raufer, M Ravonel, M Raymond, F Retiere, D Richards, J-L Ritou, A Robert, PA Rodrigues, E Rondio, M Roney, M Rooney, D Ross, B Rossi, S Roth, A Rubbia, D Ruterbories, R Sacco, S Sadler, K Sakashita, F Sanchez, A Sarrat, K Sasaki, P Schaack, J Schmidt, K Scholberg, J Schwehr, M Scott, DI Scully, Y Seiya, T Sekiguchi, H Sekiya, G Sheffer, M Shibata, Y Shimizu, M Shiozawa, S Short, M Siyad, D Smith, RJ Smith, M Smy, J Sobczyk, H Sobel, S Sooriyakumaran, M Sorel, J Spitz, A Stahl, P Stamoulis, O Star, J Statter, L Stawnyczy, J Steinmann, J Steffens, B Still, M Stodulski, J Stone, C Strabel, T Strauss, R Sulej, P Sutcliffe, A Suzuki, K Suzuki, S Suzuki, SY Suzuki, Y Suzuki, Y Suzuki, J Swierblewski, T Szeglowski, M Szeptycka, R Tacik, M Tada, AS Tadepalli, M Taguchi, S Takahashi, A Takeda, Y Takenaga, Y Takeuchi, HA Tanaka, K Tanaka, M Tanaka, MM Tanaka, N Tanimoto, K Tashiro, IJ Taylor, A Terashima, D Terhorst, R Terri, LF Thompson, A Thorley, M Thorpe, W Toki, T Tomaru, Y Totsuka, C Touramanis, T Tsukamoto, V Tvaskis, M Tzanov, Y Uchida, K Ueno, M Usseglio, A Vacheret, M Vagins, JF Van Schalkwyk, J-C Vanel, G Vasseur, O Veledar, P Vincent, T Wachala, AV Waldron, CW Walter, PJ Wanderer, MA Ward, GP Ward, D Wark, D Warner, MO Wascko, A Weber, R Wendell, J Wendland, N West, LH Whitehead, G Wikstr枚m, RJ Wilkes, MJ Wilking, Z Williamson, JR Wilson, RJ Wilson, K Wong, T Wongjirad, S Yamada, Y Yamada, A Yamamoto, K Yamamoto, Y Yamanoi, H Yamaoka, C Yanagisawa, T Yano, S Yen, N Yershov, M Yokoyama, A Zalewska, J Zalipska, K Zaremba, M Ziembicki, ED Zimmerman, M Zito, J Zmuda

Top quark mass measurement using the template method at CDF

Physical Review D - Particles, Fields, Gravitation and Cosmology 83:11 (2011)

Authors:

T Aaltonen, B Alvarez Gonz谩lez, 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

Abstract:

We present a measurement of the top quark mass in the lepton+jets and dilepton channels of tt虅 decays using the data sample corresponding to an integrated luminosity of 5.6fb-1 of pp虅 collisions at Tevatron with 鈭歴=1.96TeV, collected with the CDF II detector. We construct templates of two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the W decays in the lepton+jets channel, and a reconstructed top quark mass and mT2, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of Mtop=172.1卤1.1(stat)卤0. 9(syst)GeV/c2. 漏 2011 American Physical Society.

Measurement of underlying event characteristics using charged particles in pp collisions at 鈭歴=900GeV and 7 TeV with the ATLAS detector

Physical Review D - Particles, Fields, Gravitation and Cosmology 83:11 (2011)

Authors:

G Aad, B Abbott, J Abdallah, AA Abdelalim, A Abdesselam, O Abdinov, B Abi, M Abolins, H Abramowicz, H Abreu, E Acerbi, BS Acharya, M Ackers, DL Adams, TN Addy, J Adelman, M Aderholz, S Adomeit, P Adragna, T Adye, S Aefsky, JA Aguilar-Saavedra, M Aharrouche, SP Ahlen, F Ahles, A Ahmad, H Ahmed, M Ahsan, G Aielli, T Akdogan, TPA 脕kesson, G Akimoto, AV Akimov, MS Alam, MA Alam, S Albrand, M Aleksa, IN Aleksandrov, M Aleppo, F Alessandria, C Alexa, G Alexander, G Alexandre, T Alexopoulos, M Alhroob, M Aliev, G Alimonti, J Alison, M Aliyev, PP Allport, SE Allwood-Spiers, J Almond, A Aloisio, R Alon, A Alonso, J Alonso, MG Alviggi, K Amako, P Amaral, C Amelung, VV Ammosov, A Amorim, G Amor贸s, N Amram, C Anastopoulos, T Andeen, CF Anders, KJ Anderson, A Andreazza, V Andrei, ML Andrieux, XS Anduaga, A Angerami, F Anghinolfi, N Anjos, A Annovi, A Antonaki, M Antonelli, S Antonelli, J Antos, B Antunovic, F Anulli, S Aoun, R Apolle, G Arabidze, I Aracena, Y Arai, ATH Arce, JP Archambault, S Arfaoui, JF Arguin, T Argyropoulos, E Arik, M Arik, AJ Armbruster, KE Arms, SR Armstrong, O Arnaez, C Arnault, A Artamonov

Abstract:

Measurements of charged particle distributions, sensitive to the underlying event, have been performed with the ATLAS detector at the LHC. The measurements are based on data collected using a minimum-bias trigger to select proton-proton collisions at center-of-mass energies of 900 GeV and 7 TeV. The "underlying event" is defined as those aspects of a hadronic interaction attributed not to the hard scattering process, but rather to the accompanying interactions of the rest of the proton. Three regions are defined in azimuthal angle with respect to the highest transverse momentum charged particle in the event, such that the region transverse to the dominant momentum-flow is most sensitive to the underlying event. In each of these regions, distributions of the charged particle multiplicity, transverse momentum density, and average pT are measured. The data show generally higher underlying event activity than that predicted by Monte Carlo models tuned to pre-LHC data. 漏 2011 American Physical Society.