Observation of B0(s) →j/ψp p decays and precision measurements of the B0(s) masses

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  • LHCb Collaboration
  • R. Aaij
  • C. Abellán Beteta
  • B. Adeva
  • M. Adinolfi
  • C. A. Aidala
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  • J. Albrecht
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  • M. Alexander
  • A. Alfonso Albero
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  • S. Amerio
  • Y. Amhis
  • L. An
  • L. Anderlini
  • G. Andreassi
  • M. Andreotti
  • J. E. Andrews
  • F. Archilli
  • J. Arnau Romeu
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  • B. Audurier
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  • J. J. Back
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  • W. Baldini
  • Simone Bifani
  • R. Calladine
  • G. Chatzikonstantinidis
  • N. Farley
  • P. Griffith
  • Philip Ilten
  • Cristina Lazzeroni
  • L. Pescatore
  • J. Plews
  • Dmitry Popov
  • Antonino Sergi
  • Mark Slater
  • Nigel Watson
  • K. A. Zarebski

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  • Nikhef National Institute for Subatomic Physics
  • University of Zurich
  • Universidad de Santiago de Compostela
  • University of Bristol
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  • University of Cincinnati
  • Laboratori Nazionali dell'Infn di Frascati
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  • Institute of Physics
  • Max-Planck-Institut für Kernphysik (MPIK)
  • Ecole Polytechnique Federale de Lausanne


The first observation of the decays B0(s) →J/ψpp is reported, using proton-proton collision data corresponding to an integrated luminosity of 5.2 fb-1, collected with the LHCb detector. These decays are suppressed due to limited available phase space, as well as due to Okubo-Zweig-Iizuka or Cabibbo suppression. The measured branching fractions are B(B0→J/ψpp)=[4.51±0.40(stat)±0.44(syst)]×10-7, B(B0s→J/ψpp)=[3.58±0.19(stat)±0.39(syst)]×10-6. For the B0s meson, the result is much higher than the expected value of O(10-9). The small available phase space in these decays also allows for the most precise single measurement of both the B0 mass as 5279.74±0.30(stat)±0.10(syst) MeV and the B0s mass as 5366.85±0.19(stat)±0.13(syst) MeV.


Original languageEnglish
Article number191804
Number of pages10
JournalPhysical Review Letters
Issue number19
Publication statusPublished - 17 May 2019

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