Ratio FK/Fπ in QCD

S. Dürr, Z. Fodor, C. Hoelbling, S. D. Katz, S. Krieg, T. Kurth, L. Lellouch, T. Lippert, A. Ramos, K. K. Szabó

Research output: Contribution to journalArticlepeer-review

82 Scopus citations


We determine the ratio FK/Fπ in QCD with Nf=2+1 flavors of sea quarks, based on a series of lattice calculations with three different lattice spacings, large volumes, and a simulated pion mass reaching down to about 190 MeV. We obtain FK/Fπ=1.192(7)stat(6)syst. This result is then used to give an updated value of the Cabibbo-Kobayashi-Maskawa) matrix element |Vus|. The unitarity relation for the first row of this matrix is found to be well observed.

Original languageEnglish (US)
Article number054507
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number5
StatePublished - Mar 22 2010

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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