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RESEARCH PRODUCT

Evidence for Spin correlation in tt̄ production

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Made available in DSpace on 2022-04-29T03:09:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-19 We present a measurement of the ratio of events with correlated t and t̄ spins to the total number of tt̄ events. This ratio f is evaluated using a matrix-element-based approach in 729 tt̄ candidate events with a single lepton (electron or muon) and at least four jets. The analyzed pp̄ collisions data correspond to an integrated luminosity of 5.3fb -1 and were collected with the D0 detector at the Fermilab Tevatron collider operating at a center-of-mass energy √s=1.96TeV. Combining this result with a recent measurement of f in dileptonic final states, we find f in agreement with the standard model. In addition, the combination provides evidence for the presence of spin correlation in tt̄ events with a significance of more than 3 standard deviations. © 2012 American Physical Society. Universidad de Buenos Aires, Buenos Aires LAFEX Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro Universidade Do Estado Do Rio de Janeiro, Rio de Janeiro Universidade Federal Do ABC, Santo André Instituto de Física Teórica Universidade Estadual Paulista, São Paulo University of Science and Technology of China Universidad de Los Andes Charles University Faculty of Mathematics and Physics Center for Particle Physics, Prague Czech Technical University in Prague, Prague Center for Particle Physics Institute of Physics Academy of Sciences of the Czech Republic, Prague Universidad San Francisco de Quito, Quito LPC Université Blaise Pascal CNRS/IN2P3, Clermont LPSC Université Joseph Fourier Grenoble 1 Institut National Polytechnique de Grenoble, Grenoble CPPM Aix-Marseille Université CNRS/IN2P3, Marseille LAL, Université Paris-Sud CNRS/IN2P3, Orsay LPNHE Universités Paris VI and VII CNRS/IN2P3, Paris CEA Irfu SPP, Saclay IPHC Université de Strasbourg CNRS/IN2P3, Strasbourg IPNL Université Lyon 1 CNRS/IN2P3, Villeurbanne III. Physikalisches Institut A RWTH Aachen University, Aachen Physikalisches Institut Universität Freiburg, Freiburg II. Physikalisches Institut Georg-August-Universität Göttingen, Göttingen Institut für Physik Universität Mainz, Mainz Ludwig-Maximilians-Universität München, München Fachbereich Physik Bergische Universität Wuppertal, Wuppertal Panjab University, Chandigarh Delhi University, Delhi Tata Institute of Fundamental Research, Mumbai University College Dublin, Dublin Korea Detector Laboratory Korea University, Seoul CINVESTAV, Mexico City Nikhef Science Park, Amsterdam Radboud University Nijmegen Netherlands and Nikhef Science Park, Amsterdam Joint Institute for Nuclear Research, Dubna Institute for Theoretical and Experimental Physics, Moscow Moscow State University, Moscow Institute for High Energy Physics, Protvino Petersburg Nuclear Physics Institute, St. Petersburg Institució Catalana de Recerca i Estudis Avançats (ICREA) Institut de Física d'Altes Energies (IFAE), Barcelona Stockholm University Stockholm and Uppsala University, Uppsala Lancaster University, Lancaster LA1 4YB Imperial College London, London SW7 2AZ University of Manchester, Manchester M13 9PL University of Arizona, Tucson, AZ 85721 University of California Riverside, Riverside, CA 92521 Florida State University, Tallahassee, FL 32306 Fermi National Accelerator Laboratory, Batavia, IL 60510 University of Illinois at Chicago, Chicago, IL 60607 Northern Illinois University, DeKalb, IL 60115 Northwestern University, Evanston, IL 60208 Indiana University, Bloomington, IN 47405 Purdue University Calumet, Hammond, IN 46323 University of Notre Dame, Notre Dame, IN 46556 Iowa State University, Ames, IA 50011 University of Kansas, Lawrence, KS 66045 Kansas State University, Manhattan, KS 66506 Louisiana Tech University, Ruston, LA 71272 Boston University, Boston, MA 02215 Northeastern University, Boston, MA 02115 University of Michigan, Ann Arbor, MI 48109 Michigan State University, East Lansing, MI 48824 University of Mississippi, University, MS 38677 University of Nebraska, Lincoln, NE 68588 Rutgers University, Piscataway, NJ 08855 Princeton University, Princeton, NJ 08544 State University of New York, Buffalo, NY 14260 Columbia University, New York, NY 10027 University of Rochester, Rochester, NY 14627 State University of New York, Stony Brook, NY 11794 Brookhaven National Laboratory, Upton, NY 11973 Langston University, Langston, OK 73050 University of Oklahoma, Norman, OK 73019 Oklahoma State University, Stillwater, OK 74078 Brown University, Providence, RI 02912 University of Texas, Arlington, TX 76019 Southern Methodist University, Dallas, TX 75275 Rice University, Houston, TX 77005 University of Virginia, Charlottesville, VA 22901 University of Washington, Seattle, WA 98195 Université de Lyon, Lyon Augustana College, Sioux Falls, SD University of Liverpool, Liverpool UPIITA-IPN, Mexico City SLAC, Menlo Park, CA University College London, London Centro de Investigacion en Computacion-IPN, Mexico City ECFM Universidad Autonoma de Sinaloa, Culiacán Universität Bern, Bern Instituto de Física Teórica Universidade Estadual Paulista, São Paulo