Observation of an Excited B_{c}^{+} State
Affiliations
- 1 Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands.
- 2 Physik-Institut, Universität Zürich, Zürich, Switzerland.
- 3 Instituto Galego de Física de Altas Enerxías (IGFAE), Universidade de Santiago de Compostela, Santiago de Compostela, Spain.
- 4 H.H. Wills Physics Laboratory, University of Bristol, Bristol, United Kingdom.
- 5 University of Michigan, Ann Arbor, United States (associated with Syracuse University, Syracuse, NY, United States).
- 6 Université Clermont Auvergne, CNRS/IN2P3, LPC, Clermont-Ferrand, France.
- 7 University of Cincinnati, Cincinnati, OH, United States.
- 8 INFN Laboratori Nazionali di Frascati, Frascati, Italy.
- 9 Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany.
- 10 European Organization for Nuclear Research (CERN), Geneva, Switzerland.
- 11 School of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom.
- 12 ICCUB, Universitat de Barcelona, Barcelona, Spain.
- 13 Petersburg Nuclear Physics Institute NRC Kurchatov Institute (PNPI NRC KI), Gatchina, Russia, St.Petersburg, Russia.
- 14 Imperial College London, London, United Kingdom.
- 15 Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.
- 16 LAL, Univ. Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, Orsay, France.
- 17 INFN Sezione di Firenze, Firenze, Italy.
- 18 Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
- 19 INFN Sezione di Ferrara, Ferrara, Italy.
- 20 University of Maryland, College Park, MD, United States.
- 21 Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany.
- 22 Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France.
- 23 Institute for High Energy Physics NRC Kurchatov Institute (IHEP NRC KI), Protvino, Russia, Protvino, Russia.
- 24 Syracuse University, Syracuse, NY, United States.
- 25 Yandex School of Data Analysis, Moscow, Russia.
- 26 INFN Sezione di Cagliari, Monserrato, Italy.
- 27 Department of Physics, University of Warwick, Coventry, United Kingdom.
- 28 School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom.
- 29 INFN Sezione di Genova, Genova, Italy.
- 30 National University of Science and Technology "MISIS", Moscow, Russia (associated with Institute of Theoretical and Experimental Physics NRC Kurchatov Institute (ITEP NRC KI), Moscow, Russia, Moscow, Russia).
- 31 National Center for Nuclear Research (NCBJ), Warsaw, Poland.
- 32 INFN Sezione di Pisa, Pisa, Italy.
- 33 Centro Brasileiro de Pesquisas Físicas (CBPF), Rio de Janeiro, Brazil.
- 34 University of Chinese Academy of Sciences, Beijing, China (associated with Center for High Energy Physics, Tsinghua University, Beijing, China).
- 35 INFN Sezione di Milano-Bicocca, Milano, Italy.
- 36 LPNHE, Sorbonne Université, Paris Diderot Sorbonne Paris Cité, CNRS/IN2P3, Paris, France.
- 37 I. Physikalisches Institut, RWTH Aachen University, Aachen, Germany.
- 38 Institute of Nuclear Physics, Moscow State University (SINP MSU), Moscow, Russia.
- 39 INFN Sezione di Padova, Padova, Italy.
- 40 INFN Sezione di Bologna, Bologna, Italy.
- 41 Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom.
- 42 Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland.
- 43 University of Birmingham, Birmingham, United Kingdom.
- 44 Department of Physics, University of Oxford, Oxford, United Kingdom.
- 45 INFN Sezione di Roma La Sapienza, Roma, Italy.
- 46 Massachusetts Institute of Technology, Cambridge, MA, United States.
- 47 Budker Institute of Nuclear Physics (SB RAS), Novosibirsk, Russia.
- 48 Oliver Lodge Laboratory, University of Liverpool, Liverpool, United Kingdom.
- 49 School of Physics and Technology, Wuhan University, Wuhan, China (associated with Center for High Energy Physics, Tsinghua University, Beijing, China).
- 50 INFN Sezione di Roma Tor Vergata, Roma, Italy.
- 51 Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IN2P3-LAPP, Annecy, France.
- 52 Center for High Energy Physics, Tsinghua University, Beijing, China.
- 53 School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom.
- 54 Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania.
- 55 Los Alamos National Laboratory (LANL), Los Alamos, United States (associated with Syracuse University, Syracuse, NY, United States).
- 56 Institute of Theoretical and Experimental Physics NRC Kurchatov Institute (ITEP NRC KI), Moscow, Russia, Moscow, Russia.
- 57 INFN Sezione di Bari, Bari, Italy.
- 58 Max-Planck-Institut für Kernphysik (MPIK), Heidelberg, Germany.
- 59 AGH-University of Science and Technology, Faculty of Physics and Applied Computer Science, Kraków, Poland.
- 60 National Research University Higher School of Economics, Moscow, Russia.
- 61 Institute of Particle Physics, Central China Normal University, Wuhan, Hubei, China (associated with Center for High Energy Physics, Tsinghua University, Beijing, China).
- 62 NSC Kharkiv Institute of Physics and Technology (NSC KIPT), Kharkiv, Ukraine.
- 63 STFC Rutherford Appleton Laboratory, Didcot, United Kingdom.
- 64 Institute for Nuclear Research of the Russian Academy of Sciences (INR RAS), Moscow, Russia.
- 65 INFN Sezione di Milano, Milano, Italy.
- 66 Instituto de Fisica Corpuscular, Centro Mixto Universidad de Valencia-CSIC, Valencia, Spain (associated with ICCUB, Universitat de Barcelona, Barcelona, Spain).
- 67 South China Normal University, Guangzhou, China (associated with Center for High Energy Physics, Tsinghua University, Beijing, China).
- 68 Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, Brazil (associated with Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil).
- 69 Institut für Physik, Universität Rostock, Rostock, Germany (associated with Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany).
- 70 Laboratory of Mathematical and Subatomic Physics, Constantine, Algeria (associated with Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil).
- 71 Nikhef National Institute for Subatomic Physics and VU University Amsterdam, Amsterdam, Netherlands.
- 72 National Research Tomsk Polytechnic University, Tomsk, Russia (associated with Institute of Theoretical and Experimental Physics NRC Kurchatov Institute (ITEP NRC KI), Moscow, Russia, Moscow, Russia).
- 73 Institute for Nuclear Research of the National Academy of Sciences (KINR), Kyiv, Ukraine.
- 74 Institute Of High Energy Physics (ihep), Beijing, China.
- 75 National Research Centre Kurchatov Institute, Moscow, Russia (associated with Institute of Theoretical and Experimental Physics NRC Kurchatov Institute (ITEP NRC KI), Moscow, Russia, Moscow, Russia).
- 76 School of Physics, University College Dublin, Dublin, Ireland.
- 77 Departamento de Fisica, Universidad Nacional de Colombia, Bogota, Colombia (associated with LPNHE, Sorbonne Université, Paris Diderot Sorbonne Paris Cité, CNRS/IN2P3, Paris, France).
- 78 Van Swinderen Institute, University of Groningen, Groningen, Netherlands (associated with Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands).
- PMID: 31298897
- DOI: 10.1103/PhysRevLett.122.232001
Observation of an Excited B_{c}^{+} State
Authors
Affiliations
- 1 Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands.
- 2 Physik-Institut, Universität Zürich, Zürich, Switzerland.
- 3 Instituto Galego de Física de Altas Enerxías (IGFAE), Universidade de Santiago de Compostela, Santiago de Compostela, Spain.
- 4 H.H. Wills Physics Laboratory, University of Bristol, Bristol, United Kingdom.
- 5 University of Michigan, Ann Arbor, United States (associated with Syracuse University, Syracuse, NY, United States).
- 6 Université Clermont Auvergne, CNRS/IN2P3, LPC, Clermont-Ferrand, France.
- 7 University of Cincinnati, Cincinnati, OH, United States.
- 8 INFN Laboratori Nazionali di Frascati, Frascati, Italy.
- 9 Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany.
- 10 European Organization for Nuclear Research (CERN), Geneva, Switzerland.
- 11 School of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom.
- 12 ICCUB, Universitat de Barcelona, Barcelona, Spain.
- 13 Petersburg Nuclear Physics Institute NRC Kurchatov Institute (PNPI NRC KI), Gatchina, Russia, St.Petersburg, Russia.
- 14 Imperial College London, London, United Kingdom.
- 15 Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.
- 16 LAL, Univ. Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, Orsay, France.
- 17 INFN Sezione di Firenze, Firenze, Italy.
- 18 Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
- 19 INFN Sezione di Ferrara, Ferrara, Italy.
- 20 University of Maryland, College Park, MD, United States.
- 21 Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany.
- 22 Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France.
- 23 Institute for High Energy Physics NRC Kurchatov Institute (IHEP NRC KI), Protvino, Russia, Protvino, Russia.
- 24 Syracuse University, Syracuse, NY, United States.
- 25 Yandex School of Data Analysis, Moscow, Russia.
- 26 INFN Sezione di Cagliari, Monserrato, Italy.
- 27 Department of Physics, University of Warwick, Coventry, United Kingdom.
- 28 School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom.
- 29 INFN Sezione di Genova, Genova, Italy.
- 30 National University of Science and Technology "MISIS", Moscow, Russia (associated with Institute of Theoretical and Experimental Physics NRC Kurchatov Institute (ITEP NRC KI), Moscow, Russia, Moscow, Russia).
- 31 National Center for Nuclear Research (NCBJ), Warsaw, Poland.
- 32 INFN Sezione di Pisa, Pisa, Italy.
- 33 Centro Brasileiro de Pesquisas Físicas (CBPF), Rio de Janeiro, Brazil.
- 34 University of Chinese Academy of Sciences, Beijing, China (associated with Center for High Energy Physics, Tsinghua University, Beijing, China).
- 35 INFN Sezione di Milano-Bicocca, Milano, Italy.
- 36 LPNHE, Sorbonne Université, Paris Diderot Sorbonne Paris Cité, CNRS/IN2P3, Paris, France.
- 37 I. Physikalisches Institut, RWTH Aachen University, Aachen, Germany.
- 38 Institute of Nuclear Physics, Moscow State University (SINP MSU), Moscow, Russia.
- 39 INFN Sezione di Padova, Padova, Italy.
- 40 INFN Sezione di Bologna, Bologna, Italy.
- 41 Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom.
- 42 Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland.
- 43 University of Birmingham, Birmingham, United Kingdom.
- 44 Department of Physics, University of Oxford, Oxford, United Kingdom.
- 45 INFN Sezione di Roma La Sapienza, Roma, Italy.
- 46 Massachusetts Institute of Technology, Cambridge, MA, United States.
- 47 Budker Institute of Nuclear Physics (SB RAS), Novosibirsk, Russia.
- 48 Oliver Lodge Laboratory, University of Liverpool, Liverpool, United Kingdom.
- 49 School of Physics and Technology, Wuhan University, Wuhan, China (associated with Center for High Energy Physics, Tsinghua University, Beijing, China).
- 50 INFN Sezione di Roma Tor Vergata, Roma, Italy.
- 51 Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IN2P3-LAPP, Annecy, France.
- 52 Center for High Energy Physics, Tsinghua University, Beijing, China.
- 53 School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom.
- 54 Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania.
- 55 Los Alamos National Laboratory (LANL), Los Alamos, United States (associated with Syracuse University, Syracuse, NY, United States).
- 56 Institute of Theoretical and Experimental Physics NRC Kurchatov Institute (ITEP NRC KI), Moscow, Russia, Moscow, Russia.
- 57 INFN Sezione di Bari, Bari, Italy.
- 58 Max-Planck-Institut für Kernphysik (MPIK), Heidelberg, Germany.
- 59 AGH-University of Science and Technology, Faculty of Physics and Applied Computer Science, Kraków, Poland.
- 60 National Research University Higher School of Economics, Moscow, Russia.
- 61 Institute of Particle Physics, Central China Normal University, Wuhan, Hubei, China (associated with Center for High Energy Physics, Tsinghua University, Beijing, China).
- 62 NSC Kharkiv Institute of Physics and Technology (NSC KIPT), Kharkiv, Ukraine.
- 63 STFC Rutherford Appleton Laboratory, Didcot, United Kingdom.
- 64 Institute for Nuclear Research of the Russian Academy of Sciences (INR RAS), Moscow, Russia.
- 65 INFN Sezione di Milano, Milano, Italy.
- 66 Instituto de Fisica Corpuscular, Centro Mixto Universidad de Valencia-CSIC, Valencia, Spain (associated with ICCUB, Universitat de Barcelona, Barcelona, Spain).
- 67 South China Normal University, Guangzhou, China (associated with Center for High Energy Physics, Tsinghua University, Beijing, China).
- 68 Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, Brazil (associated with Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil).
- 69 Institut für Physik, Universität Rostock, Rostock, Germany (associated with Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany).
- 70 Laboratory of Mathematical and Subatomic Physics, Constantine, Algeria (associated with Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil).
- 71 Nikhef National Institute for Subatomic Physics and VU University Amsterdam, Amsterdam, Netherlands.
- 72 National Research Tomsk Polytechnic University, Tomsk, Russia (associated with Institute of Theoretical and Experimental Physics NRC Kurchatov Institute (ITEP NRC KI), Moscow, Russia, Moscow, Russia).
- 73 Institute for Nuclear Research of the National Academy of Sciences (KINR), Kyiv, Ukraine.
- 74 Institute Of High Energy Physics (ihep), Beijing, China.
- 75 National Research Centre Kurchatov Institute, Moscow, Russia (associated with Institute of Theoretical and Experimental Physics NRC Kurchatov Institute (ITEP NRC KI), Moscow, Russia, Moscow, Russia).
- 76 School of Physics, University College Dublin, Dublin, Ireland.
- 77 Departamento de Fisica, Universidad Nacional de Colombia, Bogota, Colombia (associated with LPNHE, Sorbonne Université, Paris Diderot Sorbonne Paris Cité, CNRS/IN2P3, Paris, France).
- 78 Van Swinderen Institute, University of Groningen, Groningen, Netherlands (associated with Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands).
- PMID: 31298897
- DOI: 10.1103/PhysRevLett.122.232001
Abstract
Using pp collision data corresponding to an integrated luminosity of 8.5 fb^{-1} recorded by the LHCb experiment at center-of-mass energies of sqrt[s]=7, 8, and 13 TeV, the observation of an excited B_{c}^{+} state in the B_{c}^{+}π^{+}π^{-} invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(B_{c}^{+}) MeV/c^{2}, where the last uncertainty is due to the limited knowledge of the B_{c}^{+} mass. It is consistent with expectations of the B_{c}^{*}(2^{3}S_{1})^{+} state reconstructed without the low-energy photon from the B_{c}^{*}(1^{3}S_{1})^{+}→B_{c}^{+}γ decay following B_{c}^{*}(2^{3}S_{1})^{+}→B_{c}^{*}(1^{3}S_{1})^{+}π^{+}π^{-}. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(B_{c}^{+}) MeV/c^{2}, and is consistent with the B_{c}(2^{1}S_{0})^{+} state. These mass measurements are the most precise to date.