Improved limit on the branching fraction of the rare decay K0 s→μ+ μ-

Research output: Contribution to journalArticlepeer-review


  • LHCb Collaboration

Colleges, School and Institutes

External organisations

  • CERN
  • Universidad de Santiago de Compostela
  • University of Bristol
  • LPC
  • University of Cincinnati
  • TU Dortmund University, Germany
  • University of Glasgow
  • Institution Nikhef National Institute for Subatomic Physics
  • Petersburg Nuclear Physics Institute (PNPI)
  • Imperial College London
  • Universidade Federal Do Rio de Janeiro
  • INFN Padova
  • IN2P3
  • Tsinghua University
  • Sezione INFN di Firenze
  • Ecole Polytechnique Federale de Lausanne
  • 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
  • University of Warwick
  • Universitat de Barcelona
  • Pontifícia Universidade Católica Do Rio de Janeiro
  • Yandex School of Data Analysis


A search for the decay KS0→μ+μ- is performed, based on a data sample of proton-proton collisions corresponding to an integrated luminosity of 3fb-1, collected by the LHCb experiment at centre-of-mass energies of 7 and 8TeV. The observed yield is consistent with the background-only hypothesis, yielding a limit on the branching fraction of B(KS0→μ+μ-)<0.8(1.0)×10-9 at 90%(95%) confidence level. This result improves the previous upper limit on the branching fraction by an order of magnitude.


Original languageEnglish
Article number678
JournalEuropean Physical Journal C
Issue number10
Publication statusPublished - 13 Oct 2017