arXiv:1001.4692·v1·High Energy Physics — Lattice
The ratio FK/Fpi in QCD
S. Durr🇩🇪 · Z. Fodor🇩🇪 · C. Hoelbling🇩🇪 · S. D. Katz🇩🇪 · S. Krieg🇺🇸 · T. Kurth🇩🇪 · L. Lellouch🇫🇷 · T. Lippert🇩🇪 · A. Ramos🇫🇷 · K. K. Szabo🇩🇪
Abstract
We determine the ratio FK/Fpi 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/Fpi=1.192 +/- 0.007(stat) +/- 0.006(syst). This result is then used to give an updated value of the CKM matrix element |Vus|. The unitarity relation for the first row of this matrix is found to be well observed.
Comments: 15 pages, 4 figures, 2 tables