Determination of |V(us)|| from a lattice QCD calculation of the K → πℓν semileptonic form factor with physical quark masses.
We calculate the kaon semileptonic form factor f+(0) from lattice QCD, working, for the first time, at the physical light-quark masses. We use gauge configurations generated by the MILC Collaboration with Nf = 2 + 1 + 1 flavors of sea quarks, which incorporate the effects of dynamical charm quarks as well as those of up, down, and strange. We employ data at three lattice spacings to extrapolate to the continuum limit. Our result, f+(0) = 0.9704(32), where the error is the total statistical plus systematic uncertainty added in quadrature, is the most precise determination to date. Combining our result with the latest experimental measurements of K semileptonic decays, one obtains the Cabibbo-Kobayashi-Maskawa matrix element |V(us)| = 0.22290(74)(52), where the first error is from f+(0) and the second one is from experiment. In the first-row test of Cabibbo-Kobayashi-Maskawa unitarity, the error stemming from |V(us)| is now comparable to that from |V(ud)|.
Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA and Department of Physics and Astronomy, University of Iowa, Iowa 52242, USA.
A
A
Bazavov
Department of Physics, Washington University, St. Louis, Missouri 63130, USA.
C
C
Bernard
Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.
C M
CM
Bouchard
Physics Department, University of Utah, Salt Lake City, Utah 84112, USA.
C
C
Detar
Physics Department, University of Illinois, Urbana, Illinois 61801, USA.
Daping
D
Du
Physics Department, University of Illinois, Urbana, Illinois 61801, USA and Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA.
A X
AX
El-Khadra
Physics Department, University of Utah, Salt Lake City, Utah 84112, USA.
J
J
Foley
Liberal Arts Department, School of the Art Institute of Chicago, Chicago, Illinois 60603, USA.
E D
ED
Freeland
CAFPE and Departamento de Física Teórica y del Cosmos, Universidad de Granada, E-18071 Granada, Spain.
E
E
Gámiz
Department of Physics, Indiana University, Bloomington, Indiana 47405, USA.
Steven
S
Gottlieb
American Physical Society, Ridge, New York 11961, USA.
U M
UM
Heller
Department of Physics, University of Arizona, Tucson, Arizona 85721, USA.
Jongjeong
J
Kim
Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA.
A S
AS
Kronfeld
SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom and Department of Physics, Syracuse University, Syracuse, New York 13244, USA.
J
J
Laiho
Physics Department, University of Utah, Salt Lake City, Utah 84112, USA.
L
L
Levkova
Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA.
P B
PB
Mackenzie
Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA and RIKEN-BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973, USA.
E T
ET
Neil
Physics Department, University of Utah, Salt Lake City, Utah 84112, USA.
M B
MB
Oktay
Physics Department, University of Utah, Salt Lake City, Utah 84112, USA.
Si-Wei
SW
Qiu
Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA.
J N
JN
Simone
Department of Physics, University of California, Santa Barbara, California 93106, USA.
R
R
Sugar
Department of Physics, University of Arizona, Tucson, Arizona 85721, USA.
D
D
Toussaint
Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA.
R S
RS
Van de Water
Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA and Department of Physics, Indiana University, Bloomington, Indiana 47405, USA.
Ran
R
Zhou