Measurement of the mass difference between top and anti-top quarks in pp collisions at s=7 TeV using the ATLAS detector

doi:10.1016/j.physletb.2013.12.010

Physics Letters B

Volume 728, 20 January 2014, Pages 363-379

https://doi.org/10.1016/j.physletb.2013.12.010 Get rights and content

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Abstract

A measurement of the mass difference between top and anti-top quarks is presented. In a $4.7 {fb}^{- 1}$ data sample of proton–proton collisions at $\sqrt{s} = 7 TeV$ recorded with the ATLAS detector at the LHC, events consistent with $t \bar{t}$ production and decay into a single charged lepton final state are reconstructed. For each event, the mass difference between the top and anti-top quark candidate is calculated. A two b-tag requirement is used in order to reduce the background contribution. A maximum likelihood fit to these per-event mass differences yields $Δ m \equiv m_{t} - m_{\bar{t}} = 0.67 \pm 0.61 (stat) \pm 0.41 (syst) GeV$ , consistent with CPT invariance.

Cited by (0)

^a: Also at Department of Physics, Kingʼs College London, London, United Kingdom.

^b: Also at Laboratorio de Instrumentacao e Fisica Experimental de Particulas – LIP, Lisboa, Portugal.

^c: Also at Institute of Physics, Azerbaijan Academy of Sciences, Baku, Azerbaijan.

^d: Also at Faculdade de Ciencias and CFNUL, Universidade de Lisboa, Lisboa, Portugal.

^e: Also at Particle Physics Department, Rutherford Appleton Laboratory, Didcot, United Kingdom.

^f: Also at TRIUMF, Vancouver, BC, Canada.

^g: Also at Department of Physics, California State University, Fresno, CA, United States.

^h: Also at Novosibirsk State University, Novosibirsk, Russia.

ⁱ: Also at Department of Physics, University of Coimbra, Coimbra, Portugal.

^j: Also at Università di Napoli Parthenope, Napoli, Italy.

^k: Also at Institute of Particle Physics (IPP), Canada.

^l: Also at Department of Physics, Middle East Technical University, Ankara, Turkey.

^m: Also at Louisiana Tech University, Ruston, LA, United States.

ⁿ: Also at Dep Fisica and CEFITEC of Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.

^o: Also at CPPM, Aix-Marseille Université and CNRS/IN2P3, Marseille, France.

^p: Also at Department of Physics and Astronomy, Michigan State University, East Lansing, MI, United States.

^q: Also at Department of Financial and Management Engineering, University of the Aegean, Chios, Greece.

^r: Also at Institucio Catalana de Recerca i Estudis Avancats, ICREA, Barcelona, Spain.

^s: Also at Department of Physics, University of Cape Town, Cape Town, South Africa.

^t: Also at CERN, Geneva, Switzerland.

^u: Also at Ochadai Academic Production, Ochanomizu University, Tokyo, Japan.

^v: Also at Manhattan College, New York, NY, United States.

^w: Also at Institute of Physics, Academia Sinica, Taipei, Taiwan.

^x: Also at School of Physics and Engineering, Sun Yat-sen University, Guanzhou, China.

^y: Also at Academia Sinica Grid Computing, Institute of Physics, Academia Sinica, Taipei, Taiwan.

^z: Also at Laboratoire de Physique Nucléaire et de Hautes Energies, UPMC and Université Paris-Diderot and CNRS/IN2P3, Paris, France.

^aa: Also at School of Physical Sciences, National Institute of Science Education and Research, Bhubaneswar, India.

^ab: Also at Dipartimento di Fisica, Università La Sapienza, Roma, Italy.

^ac: Also at DSM/IRFU (Institut de Recherches sur les Lois Fondamentales de lʼUnivers), CEA Saclay (Commissariat à lʼEnergie Atomique et aux Energies Alternatives), Gif-sur-Yvette, France.

^ad: Also at Moscow Institute of Physics and Technology State University, Dolgoprudny, Russia.

^ae: Also at Section de Physique, Université de Genève, Geneva, Switzerland.

^af: Also at Departamento de Fisica, Universidade de Minho, Braga, Portugal.

^ag: Also at Department of Physics, The University of Texas at Austin, Austin, TX, United States.

^ah: Also at Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Budapest, Hungary.

^ai: Also at DESY, Hamburg and Zeuthen, Germany.

^aj: Also at International School for Advanced Studies (SISSA), Trieste, Italy.

^ak: Also at Department of Physics and Astronomy, University of South Carolina, Columbia, SC, United States.

^al: Also at Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russia.

^am: Also at Nevis Laboratory, Columbia University, Irvington, NY, United States.

^an: Also at Physics Department, Brookhaven National Laboratory, Upton, NY, United States.

^ao: Also at Moscow Engineering and Physics Institute (MEPhI), Moscow, Russia.

^ap: Also at Department of Physics, Oxford University, Oxford, United Kingdom.

^aq: Also at Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany.

^ar: Also at Department of Physics, The University of Michigan, Ann Arbor, MI, United States.

^as: Also at Discipline of Physics, University of KwaZulu-Natal, Durban, South Africa.

^⁎: Deceased.

^⋆: E-mail address: [email protected].