Evidence for an ηc(1S) π- resonance in B0→ ηc(1S) K+π- decays

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  • LHCb Collaboration
  • R. Aaij
  • C. Abellán Beteta
  • B. Adeva
  • M. Adinolfi
  • C. A. Aidala
  • Z. Ajaltouni
  • S. Akar
  • P. Albicocco
  • J. Albrecht
  • F. Alessio
  • M. Alexander
  • A. Alfonso Albero
  • G. Alkhazov
  • P. Alvarez Cartelle
  • A. A. Alves
  • S. Amato
  • S. Amerio
  • Y. Amhis
  • L. An
  • L. Anderlini
  • G. Andreassi
  • M. Andreotti
  • J. E. Andrews
  • R. B. Appleby
  • F. Archilli
  • P. d’Argent
  • J. Arnau Romeu
  • A. Artamonov
  • M. Artuso
  • K. Arzymatov
  • E. Aslanides
  • M. Atzeni
  • B. Audurier
  • S. Bachmann
  • J. J. Back
  • S. Baker
  • Simone Bifani
  • R. Calladine
  • G. Chatzikonstantinidis
  • N. Farley
  • Philip Ilten
  • Cristina Lazzeroni
  • A. Mazurov
  • J. Plews
  • Dmitry Popov
  • Antonino Sergi
  • Mark Slater
  • Nigel Watson
  • T. Williams
  • K. A. Zarebski

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  • Institution Nikhef National Institute for Subatomic Physics
  • University of Zurich
  • Universidad de Santiago de Compostela
  • University of Bristol
  • University of Michigan
  • LPC
  • University of Cincinnati
  • Laboratori Nazionali dell'Infn di Frascati
  • TU Dortmund University, Germany
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  • Imperial College London
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  • Department of Physics and Astronomy and INFN
  • University of Maryland
  • University of Manchester
  • Ruprecht-Karls-Universität Heidelberg
  • Institute for High Energy Physics (IHEP)
  • Syracuse University
  • Yandex School of Data Analysis
  • University of Warwick


A Dalitz plot analysis of B0→ηc(1S)K+π- decays is performed using data samples of pp collisions collected with the LHCb detector at centre-of-mass energies of √s=7, 8 and 13TeV, corresponding to a total integrated luminosity of 4.7fb-1. A satisfactory description of the data is obtained when including a contribution representing an exotic ηc(1S) π- resonant state. The significance of this exotic resonance is more than three standard deviations, while its mass and width are 4096±20-22+18MeV and 152±58-35+60MeV, respectively. The spin-parity assignments JP= 0+ and JP= 1- are both consistent with the data. In addition, the first measurement of the B0→ηc(1S)K+π- branching fraction is performed and gives


where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions.


Original languageEnglish
Article number1019
Number of pages23
JournalEuropean Physical Journal C
Issue number12
Early online date17 Dec 2018
Publication statusPublished - Dec 2018