Access by Xinjiang University

Measurement of the top quark forward-backward production asymmetry and its dependence on event kinematic properties

T. Aaltonen²¹, S. Amerio^40a, D. Amidei³², A. Anastassov^15,b, A. Annovi¹⁷, J. Antos¹², G. Apollinari¹⁵, J. A. Appel¹⁵, T. Arisawa⁵³ et al. (CDF Collaboration)

T. Arisawa⁵³, A. Artikov¹³, J. Asaadi⁴⁸, W. Ashmanskas¹⁵, B. Auerbach², A. Aurisano⁴⁸, F. Azfar³⁹, W. Badgett¹⁵, T. Bae²⁵, A. Barbaro-Galtieri²⁶, V. E. Barnes⁴⁴, B. A. Barnett²³, P. Barria^42c,42a, P. Bartos¹², M. Bauce^40b,40a, F. Bedeschi^42a, S. Behari¹⁵, G. Bellettini^42b,42a, J. Bellinger⁵⁵, D. Benjamin¹⁴, A. Beretvas¹⁵, A. Bhatti⁴⁶, K. R. Bland⁵, B. Blumenfeld²³, A. Bocci¹⁴, A. Bodek⁴⁵, D. Bortoletto⁴⁴, J. Boudreau⁴³, A. Boveia¹¹, L. Brigliadori^6b,6a, C. Bromberg³³, E. Brucken²¹, J. Budagov¹³, H. S. Budd⁴⁵, K. Burkett¹⁵, G. Busetto^40b,40a, P. Bussey¹⁹, P. Butti^42b,42a, A. Buzatu¹⁹, A. Calamba¹⁰, S. Camarda⁴, M. Campanelli²⁸, F. Canelli^11,15,c, B. Carls²², D. Carlsmith⁵⁵, R. Carosi^42a, S. Carrillo^16,d, B. Casal^9,e, M. Casarsa^49a, A. Castro^6b,6a, P. Catastini²⁰, D. Cauz^49a, V. Cavaliere²², M. Cavalli-Sforza⁴, A. Cerri^26,f, L. Cerrito^28,g, Y. C. Chen¹, M. Chertok⁷, G. Chiarelli^42a, G. Chlachidze¹⁵, K. Cho²⁵, D. Chokheli¹³, M. A. Ciocci^42c,42a, A. Clark¹⁸, C. Clarke⁵⁴, M. E. Convery¹⁵, J. Conway⁷, M. Corbo¹⁵, M. Cordelli¹⁷, C. A. Cox⁷, D. J. Cox⁷, M. Cremonesi^42a, D. Cruz⁴⁸, J. Cuevas^9,h, R. Culbertson¹⁵, N. d’Ascenzo^15,i, M. Datta^15,j, P. De Barbaro⁴⁵, L. Demortier⁴⁶, M. Deninno^6a, F. Devoto²¹, M. d’Errico^40b,40a, A. Di Canto^42b,42a, B. Di Ruzza^15,k, J. R. Dittmann⁵, M. D’Onofrio²⁷, S. Donati^42b,42a, M. Dorigo^49a,49b, A. Driutti^49a, K. Ebina⁵³, R. Edgar³², A. Elagin⁴⁸, R. Erbacher⁷, S. Errede²², B. Esham²², R. Eusebi⁴⁸, S. Farrington³⁹, J. P. Fernández Ramos²⁹, R. Field¹⁶, G. Flanagan^15,l, R. Forrest⁷, M. Franklin²⁰, J. C. Freeman¹⁵, H. Frisch¹¹, Y. Funakoshi⁵³, A. F. Garfinkel⁴⁴, P. Garosi^42c,42a, H. Gerberich²², E. Gerchtein¹⁵, S. Giagu^47a, V. Giakoumopoulou³, K. Gibson⁴³, C. M. Ginsburg¹⁵, N. Giokaris³, P. Giromini¹⁷, G. Giurgiu²³, V. Glagolev¹³, D. Glenzinski¹⁵, M. Gold³⁵, D. Goldin⁴⁸, A. Golossanov¹⁵, G. Gomez⁹, G. Gomez-Ceballos³⁰, M. Goncharov³⁰, O. González López²⁹, I. Gorelov³⁵, A. T. Goshaw¹⁴, K. Goulianos⁴⁶, E. Gramellini^6a, S. Grinstein⁴, C. Grosso-Pilcher¹¹, R. C. Group^52,15, J. Guimaraes da Costa²⁰, S. R. Hahn¹⁵, J. Y. Han⁴⁵, F. Happacher¹⁷, K. Hara⁵⁰, M. Hare⁵¹, R. F. Harr⁵⁴, T. Harrington-Taber^15,m, K. Hatakeyama⁵, C. Hays³⁹, J. Heinrich⁴¹, M. Herndon⁵⁵, A. Hocker¹⁵, Z. Hong⁴⁸, W. Hopkins^15,n, S. Hou¹, R. E. Hughes³⁶, U. Husemann⁵⁶, M. Hussein³³, J. Huston³³, G. Introzzi^42e,42a, M. Iori^47a,47b, A. Ivanov^7,o, E. James¹⁵, D. Jang¹⁰, B. Jayatilaka¹⁵, E. J. Jeon²⁵, S. Jindariani¹⁵, M. Jones⁴⁴, K. K. Joo²⁵, S. Y. Jun¹⁰, T. R. Junk¹⁵, M. Kambeitz²⁴, T. Kamon^25,48, P. E. Karchin⁵⁴, A. Kasmi⁵, Y. Kato^38,p, W. Ketchum^11,q, J. Keung⁴¹, B. Kilminster^15,c, D. H. Kim²⁵, H. S. Kim²⁵, J. E. Kim²⁵, M. J. Kim¹⁷, S. B. Kim²⁵, S. H. Kim⁵⁰, Y. K. Kim¹¹, Y. J. Kim²⁵, N. Kimura⁵³, M. Kirby¹⁵, K. Knoepfel¹⁵, K. Kondo^53,a, D. J. Kong²⁵, J. Konigsberg¹⁶, A. V. Kotwal¹⁴, M. Kreps²⁴, J. Kroll⁴¹, M. Kruse¹⁴, T. Kuhr²⁴, M. Kurata⁵⁰, A. T. Laasanen⁴⁴, S. Lammel¹⁵, M. Lancaster²⁸, K. Lannon^36,r, G. Latino^42c,42a, H. S. Lee²⁵, J. S. Lee²⁵, S. Leo^42a, S. Leone^42a, J. D. Lewis¹⁵, A. Limosani^14,s, E. Lipeles⁴¹, H. Liu⁵², Q. Liu⁴⁴, T. Liu¹⁵, S. Lockwitz⁵⁶, A. Loginov⁵⁶, D. Lucchesi^40b,40a, J. Lueck²⁴, P. Lujan²⁶, P. Lukens¹⁵, G. Lungu⁴⁶, J. Lys²⁶, R. Lysak^12,t, R. Madrak¹⁵, P. Maestro^42c,42a, S. Malik⁴⁶, G. Manca^27,u, A. Manousakis-Katsikakis³, F. Margaroli^47a, P. Marino^42d,42a, M. Martínez⁴, K. Matera²², M. E. Mattson⁵⁴, A. Mazzacane¹⁵, P. Mazzanti^6a, R. McNulty^27,v, A. Mehta²⁷, P. Mehtala²¹, C. Mesropian⁴⁶, T. Miao¹⁵, D. Mietlicki³², A. Mitra¹, H. Miyake⁵⁰, S. Moed¹⁵, N. Moggi^6a, C. S. Moon^15,w, R. Moore^15,x, M. J. Morello^42d,42a, A. Mukherjee¹⁵, Th. Muller²⁴, P. Murat¹⁵, M. Mussini^6b,6a, J. Nachtman^15,m, Y. Nagai⁵⁰, J. Naganoma⁵³, I. Nakano³⁷, A. Napier⁵¹, J. Nett⁴⁸, C. Neu⁵², T. Nigmanov⁴³, L. Nodulman², S. Y. Noh²⁵, O. Norniella²², L. Oakes³⁹, S. H. Oh¹⁴, Y. D. Oh²⁵, I. Oksuzian⁵², T. Okusawa³⁸, R. Orava²¹, L. Ortolan⁴, C. Pagliarone^49a, E. Palencia^9,f, P. Palni³⁵, V. Papadimitriou¹⁵, W. Parker⁵⁵, G. Pauletta^49a,49c, M. Paulini¹⁰, C. Paus³⁰, T. J. Phillips¹⁴, G. Piacentino^42a, E. Pianori⁴¹, J. Pilot³⁶, K. Pitts²², C. Plager⁸, L. Pondrom⁵⁵, S. Poprocki^15,n, K. Potamianos²⁶, F. Prokoshin^13,y, A. Pranko²⁶, F. Ptohos^17,z, G. Punzi^42b,42a, N. Ranjan⁴⁴, I. Redondo Fernández²⁹, P. Renton³⁹, M. Rescigno^47a, T. Riddick²⁸, F. Rimondi^6a,a, L. Ristori^42a,15, A. Robson¹⁹, T. Rodriguez⁴¹, S. Rolli^51,aa, M. Ronzani^42b,42a, R. Roser¹⁵, J. L. Rosner¹¹, F. Ruffini^42c,42a, A. Ruiz⁹, J. Russ¹⁰, V. Rusu¹⁵, A. Safonov⁴⁸, W. K. Sakumoto⁴⁵, Y. Sakurai⁵³, L. Santi^49a,49c, K. Sato⁵⁰, V. Saveliev^15,i, A. Savoy-Navarro^15,w, P. Schlabach¹⁵, E. E. Schmidt¹⁵, T. Schwarz³², L. Scodellaro⁹, F. Scuri^42a, S. Seidel³⁵, Y. Seiya³⁸, A. Semenov¹³, F. Sforza^42b,42a, S. Z. Shalhout⁷, T. Shears²⁷, P. F. Shepard⁴³, M. Shimojima^50,bb, M. Shochet¹¹, I. Shreyber-Tecker³⁴, A. Simonenko¹³, P. Sinervo³¹, K. Sliwa⁵¹, J. R. Smith⁷, F. D. Snider¹⁵, V. Sorin⁴, H. Song⁴³, M. Stancari¹⁵, R. St. Denis¹⁹, B. Stelzer³¹, O. Stelzer-Chilton³¹, D. Stentz^15,b, J. Strologas³⁵, Y. Sudo⁵⁰, A. Sukhanov¹⁵, I. Suslov¹³, K. Takemasa⁵⁰, Y. Takeuchi⁵⁰, J. Tang¹¹, M. Tecchio³², P. K. Teng¹, J. Thom^15,n, E. Thomson⁴¹, V. Thukral⁴⁸, D. Toback⁴⁸, S. Tokar¹², K. Tollefson³³, T. Tomura⁵⁰, D. Tonelli^15,f, S. Torre¹⁷, D. Torretta¹⁵, P. Totaro^40a, M. Trovato^42d,42a, F. Ukegawa⁵⁰, S. Uozumi²⁵, F. Vázquez^16,d, G. Velev¹⁵, C. Vellidis¹⁵, C. Vernieri^42d,42a, M. Vidal⁴⁴, R. Vilar⁹, J. Vizán^9,cc, M. Vogel³⁵, G. Volpi¹⁷, P. Wagner⁴¹, R. Wallny⁸, S. M. Wang¹, A. Warburton³¹, D. Waters²⁸, W. C. Wester, III¹⁵, D. Whiteson^41,dd, A. B. Wicklund², S. Wilbur¹¹, H. H. Williams⁴¹, J. S. Wilson³², P. Wilson¹⁵, B. L. Winer³⁶, P. Wittich^15,n, S. Wolbers¹⁵, H. Wolfe³⁶, T. Wright³², X. Wu¹⁸, Z. Wu⁵, K. Yamamoto³⁸, D. Yamato³⁸, T. Yang¹⁵, U. K. Yang^11,ee, Y. C. Yang²⁵, W. -M. Yao²⁶, G. P. Yeh¹⁵, K. Yi^15,m, J. Yoh¹⁵, K. Yorita⁵³, T. Yoshida^38,ff, G. B. Yu¹⁴, I. Yu²⁵, A. M. Zanetti^49a, Y. Zeng¹⁴, C. Zhou¹⁴, and S. Zucchelli^6b,6a (CDF Collaboration)

¹Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China
²Argonne National Laboratory, Argonne, Illinois 60439, USA
³University of Athens, 157 71 Athens, Greece
⁴Institut de Fisica d’Altes Energies, ICREA, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Barcelona), Spain
⁵Baylor University, Waco, Texas 76798, USA
^6aIstituto Nazionale di Fisica Nucleare Bologna, I-40127 Bologna, Italy
^6bUniversity of Bologna, I-40127 Bologna, Italy
⁷University of California, Davis, Davis, California 95616, USA
⁸University of California, Los Angeles, Los Angeles, California 90024, USA
⁹Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain
¹⁰Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
¹¹Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA
¹²Comenius University, 842 48 Bratislava, Slovakia; Institute of Experimental Physics, 040 01 Kosice, Slovakia
¹³Joint Institute for Nuclear Research, RU-141980 Dubna, Russia
¹⁴Duke University, Durham, North Carolina 27708, USA
¹⁵Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA
¹⁶University of Florida, Gainesville, Florida 32611, USA
¹⁷Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy
¹⁸University of Geneva, CH-1211 Geneva 4, Switzerland
¹⁹Glasgow University, Glasgow G12 8QQ, United Kingdom
²⁰Harvard University, Cambridge, Massachusetts 02138, USA
²¹Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014 Helsinki, Finland
²²University of Illinois, Urbana, Illinois 61801, USA
²³The Johns Hopkins University, Baltimore, Maryland 21218, USA
²⁴Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany
²⁵Center for High Energy Physics, Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea; Ewha Womans University, Seoul 120-750, Korea
²⁶Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
²⁷University of Liverpool, Liverpool L69 7ZE, United Kingdom
²⁸University College London, London WC1E 6BT, United Kingdom
²⁹Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain
³⁰Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
³¹Institute of Particle Physics, McGill University, Montréal, Québec H3A 2T8, Canada; Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada; University of Toronto, Toronto, Ontario M5S 1A7, Canada; and TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
³²University of Michigan, Ann Arbor, Michigan 48109, USA
³³Michigan State University, East Lansing, Michigan 48824, USA
³⁴Institution for Theoretical and Experimental Physics, ITEP, Moscow 117259, Russia
³⁵University of New Mexico, Albuquerque, New Mexico 87131, USA
³⁶The Ohio State University, Columbus, Ohio 43210, USA
³⁷Okayama University, Okayama 700-8530, Japan
³⁸Osaka City University, Osaka 588, Japan
³⁹University of Oxford, Oxford OX1 3RH, United Kingdom
^40aIstituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy
^40bUniversity of Padova, I-35131 Padova, Italy
⁴¹University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
^42aIstituto Nazionale di Fisica Nucleare Pisa, I-56127 Pisa, Italy
^42bUniversity of Pisa, I-56127 Pisa, Italy
^42cUniversity of Siena, I-56127 Pisa, Italy
^42dScuola Normale Superiore, I-56127 Pisa, Italy
^42eINFN Pavia and University of Pavia, I-27100 Pavia, Italy
⁴³University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
⁴⁴Purdue University, West Lafayette, Indiana 47907, USA
⁴⁵University of Rochester, Rochester, New York 14627, USA
⁴⁶The Rockefeller University, New York, New York 10065, USA
^47aIstituto Nazionale di Fisica Nucleare, Sezione di Roma 1, I-00185 Roma, Italy
^47bSapienza Università di Roma, I-00185 Roma, Italy
⁴⁸Texas A&M University, College Station, Texas 77843, USA
^49aIstituto Nazionale di Fisica Nucleare Trieste/Udine, I-34127 Trieste, Italy
^49bUniversity of Trieste, I-34127 Trieste, Italy
^49cUniversity of Udine, I-33100 Udine, Italy
⁵⁰University of Tsukuba, Tsukuba, Ibaraki 305, Japan
⁵¹Tufts University, Medford, Massachusetts 02155, USA
⁵²University of Virginia, Charlottesville, Virginia 22906, USA
⁵³Waseda University, Tokyo 169, Japan
⁵⁴Wayne State University, Detroit, Michigan 48201, USA
⁵⁵University of Wisconsin, Madison, Wisconsin 53706, USA
⁵⁶Yale University, New Haven, Connecticut 06520, USA

^aDeceased.
^bVisitor from Northwestern University, Evanston, IL 60208, USA.
^cVisitor from University of Zürich, 8006 Zürich, Switzerland.
^dVisitor from Universidad Iberoamericana, Lomas de Santa Fe, México, C.P. 01219, Distrito Federal.
^eVisitor from ETH, 8092 Zürich, Switzerland.
^fVisitor from CERN, CH-1211 Geneva, Switzerland.
^gVisitor from Queen Mary, University of London, London E1 4NS, United Kingdom.
^hVisitor from Universidad de Oviedo, E-33007 Oviedo, Spain.
ⁱVisitor from National Research Nuclear University, Moscow 115409, Russia.
^jVisitor from Hampton University, Hampton, VA 23668, USA.
^kVisitor from Brookhaven National Laboratory, Upton, NY 11973, USA.
^lVisitor from Muons, Inc., Batavia, IL 60510, USA.
^mVisitor from University of Iowa, Iowa City, IA 52242, USA.
ⁿVisitor from Cornell University, Ithaca, NY 14853, USA.
^oVisitor from Kansas State University, Manhattan, KS 66506, USA.
^pVisitor from Kinki University, Higashi-Osaka City 577-8502, Japan.
^qVisitor from Los Alamos National Laboratory, Los Alamos, NM 87544, USA.
^rVisitor from University of Notre Dame, Notre Dame, IN 46556, USA.
^sVisitor from University of Melbourne, Victoria 3010, Australia.
^tVisitor from Institute of Physics, Academy of Sciences of the Czech Republic, 182 21, Czech Republic.
^uVisitor from Istituto Nazionale di Fisica Nucleare, Sezione di Cagliari, 09042 Monserrato (Cagliari), Italy.
^vVisitor from University College Dublin, Dublin 4, Ireland.
^wVisitor from CNRS-IN2P3, Paris F-75205, France.
^xVisitor from Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
^yVisitor from Universidad Tecnica Federico Santa Maria, 110v Valparaiso, Chile.
^zVisitor from University of Cyprus, Nicosia CY-1678, Cyprus.
^aaVisitor from Office of Science, U.S. Department of Energy, Washington, DC 20585, USA.
^bbVisitor from Nagasaki Institute of Applied Science, Nagasaki 851-0193, Japan.
^ccVisitor from Universite catholique de Louvain, 1348 Louvain-La-Neuve, Belgium.
^ddVisitor from University of California Irvine, Irvine, CA 92697, USA.
^eeVisitor from University of Manchester, Manchester M13 9PL, United Kingdom.
^ffVisitor from University of Fukui, Fukui City, Fukui Prefecture 910-0017, Japan.

PDF

Phys. Rev. D 87, 092002 – Published 3 May, 2013

DOI: https://doi.org/10.1103/PhysRevD.87.092002

Abstract

We present new measurements of the inclusive forward-backward $t \bar{t}$ production asymmetry, $A_{FB}$ , and its dependence on several properties of the $t \bar{t}$ system. The measurements are performed with the full Tevatron data set recorded with the CDF II detector during $p \bar{p}$ collisions at $\sqrt{s} = 1.96 TeV$ , corresponding to an integrated luminosity of $9.4 {fb}^{- 1}$ . We measure the asymmetry using the rapidity difference $Δ y = y_{t} - y_{\bar{t}}$ . Parton-level results are derived, yielding an inclusive asymmetry of $0.164 \pm 0.047 (stat + syst)$ . We establish an approximately linear dependence of $A_{FB}$ on the top-quark pair mass $M_{t \bar{t}}$ and the rapidity difference $| Δ y |$ at detector and parton levels. Assuming the standard model, the probabilities to observe the measured values or larger for the detector-level dependencies are $7.4 \times 10^{- 3}$ and $2.2 \times 10^{- 3}$ for $M_{t \bar{t}}$ and $| Δ y |$ respectively. Lastly, we study the dependence of the asymmetry on the transverse momentum of the $t \bar{t}$ system at the detector level. These results are consistent with previous lower-precision measurements and provide additional quantification of the functional dependencies of the asymmetry.

Article Text

References (37)

L. G. Almeida, G. F. Sterman, and W. Vogelsang, Phys. Rev. D 78, 014008 (2008); O. Antunano, J. H. Kuhn, and G. V. Rodrigo, 77, 014003 (2008); M. T. Bowen, S. D. Ellis, and D. Rainwater, 73, 014008 (2006).
T. Aaltonen et al. (CDF Collaboration), Phys. Rev. D 83, 112003 (2011).
The charge-conjugate states are implied.
V. M. Abazov et al. (D0 Collaboration), Phys. Rev. D 84, 112005 (2011).
W. Hollik and D. Pagani, Phys. Rev. D 84, 093003 (2011).
J. H. Kuhn and G. Rodrigo, J. High Energy Phys. 01 (2012) 063.
A. V. Manohar and M. Trott, Phys. Lett. B 711, 313 (2012).
S. Brodsky and X.-G. Wu, arXiv:1205.1232.
P. Bärnreuther, M. Czakon, and A. Mitov, Phys. Rev. Lett. 109, 132001 (2012).
P. Skands, B. Webber, and J. Winter, J. High Energy Phys. 07 (2012) 151; K. Melnikov, A. Scharf, and M. Schulze, Phys. Rev. D 85, 054002 (2012); S. Dittmaier, P. Uwer, and S. Weinzierl, Eur. Phys. J. C 59, 625 (2009).
Some recent reviews: M. Gresham, I.-W. Kim, and K. Zurek, Phys. Rev. D 84, 034025 (2011); Q.-H. Cao, D. McKeen, J. L. Rosner, G. Shaughnessy, and C. Wagner, 81, 114004 (2010).
G. Aad et al. (ATLAS Collaboration), Eur. Phys. J. C 72, 2039 (2012); S. Chatrchyan et al. (CMS Collaboration), Phys. Lett. B 717, 129 (2012).
J. A. Aguilar-Saavedra and A. Juste, Phys. Rev. Lett. 109, 211804 (2012); E. Alvarez and E. C. Leskow, Phys. Rev. D 86, 114034 (2012); J. Drobnak, J. F. Kamenik, and J. Zupan, 86, 054022 (2012); J. Drobnak, A. L. Kagan, J. F. Kamenik, G. Perez, and J. Zupan, 86, 094040 (2012).
S. Frixione, P. Nason, and G. Ridolfi, J. High Energy Phys. 09 (2007) 126.
S. Frixione and B. R. Webber, J. High Energy Phys. 06 (2002) 029.
J. M. Campbell and R. K. Ellis, Phys. Rev. D 60, 113006 (1999).
Arguments have been made that, because the $A_{FB}$ numerator $N (Δ y > 0) - N (Δ y < 0)$ is effectively a LO calculation of the asymmetry, the LO cross section should be used in the denominator, $N (Δ y > 0) + N (Δ y < 0) \propto σ_{t \bar{t}}$ , when defining $A_{FB}$ . For the studies presented here, we use the clearly defined and self-consistent prediction that results from powheg, which, as a NLO generator includes the NLO cross section for the denominator.
J. M. Campbell and R. K. Ellis, arXiv:1204.1513.
J. Alwall, P. Demin, S. de Visscher, R. Frederix, M. Herquet, F. Maltoni, T. Plehn, D. L. Rainwater, and T. Stelzer, J. High Energy Phys. 09 (2007) 028.
We are indebted to T. Tait for the MadGraph implementation of the color-octet models.
T. Sjöstrand, S. Mrenna, and P. Skands, J. High Energy Phys. 05 (2006) 026.
G. Aad et al. (ATLAS Collaboration), J. High Energy Phys. 09 (2012) 041; S. Chatrchyan et al. (CMS Collaboration), 12 (2012) 015.
D. Acosta et al. (CDF Collaboration), Phys. Rev. D 71, 032001 (2005); The CDF II Technical Design Report, Report No. FERMILAB-PUB/390-E, 1996.
The polar angle is $θ$ and the azimuthal angle is $ϕ$ . With total energy $E$ and momentum $p$ , the transverse energy is defined as $E_{T} = E \sin θ$ and the transverse momentum is $p_{T} = p \sin θ$ . The missing transverse energy ( ${E̸}_{T}$ ) is the magnitude of ${\vec{E̸}}_{T} = - Σ_{i} E_{T}^{i} {\hat{n}}_{i}$ where ${\hat{n}}_{i}$ is a unit vector perpendicular to the beam axis and pointing to the $i$ th calorimeter tower. The pseudorapidity is $η = - \ln (\tan (θ / 2))$ .
A. Bhatti et al., Nucl. Instrum. Methods Phys. Res., Sect. A 566, 375 (2006).
D. Acosta et al. (CDF Collaboration), Phys. Rev. D 71, 052003 (2005).
M. L. Mangano, M. Moretti, F. Piccinini, R. Pittau, and A. Polosa, J. High Energy Phys. 07 (2003) 001.
T. Aaltonen et al. (CDF Collaboration), Phys. Rev. Lett. 105, 012001 (2010); D. Acosta et al. (CDF Collaboration), Phys. Rev. D 71, 052003 (2005).
A. Abulencia et al. (CDF Collaboration), Phys. Rev. D 73, 032003 (2006).
T. Aaltonen et al. (CDF Collaboration), Phys. Rev. Lett. 102, 222003 (2009).
A. Höcker and V. Kartvelishvili, Nucl. Instrum. Methods Phys. Res., Sect. A 372, 469 (1996).
T. Adye, arXiv:1105.1160; See also http://hepunx.rl.ac.uk/~adye/software/unfold/RooUnfold.html.
A. Abulencia et al. (CDF Collaboration), Phys. Rev. D 73, 032003 (2006).
T. Aaltonen et al. (CDF Collaboration), Phys. Rev. D 81, 031102(R) (2010).
G. Corcella, I. G. Knowles, G. Marchesini, S. Moretti, K. Odagiri, P. Richardson, M. H. Seymour, and B. R. Webber, J. High Energy Phys. 01 (2001) 010.
L. G. Almeida, G. F. Sterman, and W. Vogelsang, Phys. Rev. D 78, 014008 (2008).
K. Melnikov, A. Scharf, and M. Schulze (private communication).

Physical Review D

Export citation

Export citation

Measurement of the top quark forward-backward production asymmetry and its dependence on event kinematic properties

Abstract

Article Text

References (37)

Outline

Information

Filter

Filter

Article Lookup

Enter a citation