Eur. Phys. J. C (2011) 71: 1720
https://doi.org/10.1140/epjc/s10052-011-1720-4

Regular Article - Experimental Physics

Improved determination of the sample composition of dimuon events produced in collisions at TeV

¹ Institute of Physics, Academia Sinica, Taipei, Taiwan, 11529, Republic of China
² Argonne National Laboratory, Argonne, IL, 60439, USA
³ University of Athens, 157 71, Athens, Greece
⁴ Institut de Fisica d’Altes Energies, ICREA, Universitat Autonoma de Barcelona, 08193, Bellaterra (Barcelona), Spain
⁵ Baylor University, Waco, TX, 76798, USA
⁶ Istituto Nazionale di Fisica Nucleare Bologna, 40127, Bologna, Italy
⁷ Istituto Nazionale di Fisica Nucleare Bologna, University of Bologna, 40127, Bologna, Italy
⁸ University of California, Davis, Davis, CA, 95616, USA
⁹ University of California, Los Angeles, Los Angeles, CA, 90024, USA
¹⁰ Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005, Santander, Spain
¹¹ Carnegie Mellon University, Pittsburgh, PA, 15213, USA
¹² Enrico Fermi Institute, University of Chicago, Chicago, IL, 60637, USA
¹³ Comenius University, 842 48, Bratislava, Slovakia
¹⁴ Institute of Experimental Physics, 040 01, Kosice, Slovakia
¹⁵ Joint Institute for Nuclear Research, 141980, Dubna, Russia
¹⁶ Duke University, Durham, NC, 27708, USA
¹⁷ Fermi National Accelerator Laboratory, Batavia, IL, 60510, USA
¹⁸ University of Florida, Gainesville, FL, 32611, USA
¹⁹ Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, 00044, Frascati, Italy
²⁰ University of Geneva, 1211, Geneva 4, Switzerland
²¹ Glasgow University, Glasgow, G12 8QQ, UK
²² Harvard University, Cambridge, MA, 02138, USA
²³ Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, 00014, Helsinki, Finland
²⁴ University of Illinois, Urbana, IL, 61801, USA
²⁵ The Johns Hopkins University, Baltimore, MD, 21218, USA
²⁶ Center for High Energy Physics, Kyungpook National University, Daegu, 702-701, Korea
²⁷ Center for High Energy Physics, Seoul National University, Seoul, 151-742, Korea
²⁸ Center for High Energy Physics, Sungkyunkwan University, Suwon, 440-746, Korea
²⁹ Center for High Energy Physics, Korea Institute of Science and Technology Information, Daejeon, 305-806, Korea
³⁰ Center for High Energy Physics, Chonnam National University, Gwangju, 500-757, Korea
³¹ Chonbuk National University, Jeonju, 561-756, Korea
³² Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
³³ University of Liverpool, Liverpool, L69 7ZE, UK
³⁴ University College London, London, WC1E 6BT, UK
³⁵ Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, 28040, Madrid, Spain
³⁶ Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
³⁷ Institute of Particle Physics, McGill University, Montréal, Québec, H3A 2T8, Canada
³⁸ Institute of Particle Physics, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
³⁹ Institute of Particle Physics, University of Toronto, Toronto, Ontario, M5S 1A7, Canada
⁴⁰ Institute of Particle Physics, TRIUMF, Vancouver, British Columbia, V6T 2A3, Canada
⁴¹ University of Michigan, Ann Arbor, MI, 48109, USA
⁴² Michigan State University, East Lansing, MI, 48824, USA
⁴³ Institution for Theoretical and Experimental Physics, ITEP, Moscow, 117259, Russia
⁴⁴ University of New Mexico, Albuquerque, NM, 87131, USA
⁴⁵ Northwestern University, Evanston, IL, 60208, USA
⁴⁶ The Ohio State University, Columbus, OH, 43210, USA
⁴⁷ Okayama University, Okayama, 700-8530, Japan
⁴⁸ Osaka City University, Osaka, 588, Japan
⁴⁹ University of Oxford, Oxford, OX1 3RH, UK
⁵⁰ Sezione di Padova-Trento, Istituto Nazionale di Fisica Nucleare, 35131, Padova, Italy
⁵¹ Istituto Nazionale di Fisica Nucleare, University of Padova, 35131, Padova, Italy
⁵² LPNHE, UMR7585, Universite Pierre et Marie Curie/IN2P3-CNRS, Paris, 75252, France
⁵³ Istituto Nazionale di Fisica Nucleare Pisa, 56127, Pisa, Italy
⁵⁴ Istituto Nazionale di Fisica Nucleare Pisa, University of Pisa, 56127, Pisa, Italy
⁵⁵ Istituto Nazionale di Fisica Nucleare Pisa, University of Siena, 56127, Pisa, Italy
⁵⁶ Istituto Nazionale di Fisica Nucleare Pisa, Scuola Normale Superiore, 56127, Pisa, Italy
⁵⁷ University of Pittsburgh, Pittsburgh, PA, 15260, USA
⁵⁸ Purdue University, West Lafayette, IN, 47907, USA
⁵⁹ University of Rochester, Rochester, NY, 14627, USA
⁶⁰ The Rockefeller University, New York, NY, 10065, USA
⁶¹ Sezione di Roma 1, Istituto Nazionale di Fisica Nucleare, 00185, Roma, Italy
⁶² Istituto Nazionale di Fisica Nucleare, Sapienza Università di Roma, 00185, Roma, Italy
⁶³ Rutgers University, Piscataway, NJ, 08855, USA
⁶⁴ Texas A&M University, College Station, TX, 77843, USA
⁶⁵ Istituto Nazionale di Fisica Nucleare Trieste/Udine, 34100, Trieste, Italy
⁶⁶ Istituto Nazionale di Fisica Nucleare, University of Udine, 33100, Udine, Italy
⁶⁷ University of Tsukuba, Tsukuba, 305, Ibaraki, Japan
⁶⁸ Tufts University, Medford, MA, 02155, USA
⁶⁹ University of Virginia, Charlottesville, VA, 22906, USA
⁷⁰ Waseda University, Tokyo, 169, Japan
⁷¹ Wayne State University, Detroit, MI, 48201, USA
⁷² University of Wisconsin, Madison, WI, 53706, USA
⁷³ Yale University, New Haven, CT, 06520, USA

^* e-mail: ptohos@fnal.gov

Received: 29 May 2011
Revised: 13 July 2011
Published online: 23 August 2011

Abstract

We use a new method to estimate with 5% accuracy the contribution of pion and kaon in-flight-decays to the dimuon data set acquired with the CDF detector. Based on this improved estimate, we show that the total number and the properties of the collected dimuon events are not yet accounted for by ordinary sources of dimuons which also include the contributions, as measured in the data, of heavy flavor, ϒ, and Drell–Yan production in addition to muons mimicked by hadronic punchthrough. The number of unaccounted events corresponds to (12.8±3.2)% of the production. We find that (23±6)% of the unaccounted events contain additional muon candidates. For comparison, this fraction is (6.9±0.4)% for events due to production.