TY - JOUR

T1 - Vector form factor in Kl3 semileptonic decay with two flavors of dynamical domain-wall quarks

AU - Dawson, Chris

AU - Izubuchi, Taku

AU - Kaneko, Takashi

AU - Sasaki, Shoichi

AU - Soni, Amarjit

N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.

PY - 2006

Y1 - 2006

N2 - We calculate the vector form factor in K→πlν semileptonic decays at zero momentum transfer f+(0) from numerical simulations of two-flavor QCD on the lattice. Our simulations are carried out on 163×32 at a lattice spacing of 0.12fm using a combination of the DBW2 gauge and the domain-wall quark actions, which possesses excellent chiral symmetry even at finite lattice spacings. The size of fifth dimension is set to Ls=12, which leads to a residual quark mass of a few MeV. Through a set of double ratios of correlation functions, the form factor calculated on the lattice is accurately interpolated to zero momentum transfer, and then is extrapolated to the physical quark mass. We obtain f+(0)=0.968(9)(6), where the first error is statistical and the second is the systematic error due to the chiral extrapolation. Previous estimates based on a phenomenological model and chiral perturbation theory are consistent with our result. Combining with an average of the decay rate from recent experiments, our estimate of f+(0) leads to the Cabibbo-Kobayashi-Maskawa (CKM) matrix element |Vus|=0.2245(27), which is consistent with CKM unitarity. These estimates of f+(0) and |Vus| are subject to systematic uncertainties due to the finite lattice spacing and quenching of strange quarks, though nice consistency in f+(0) with previous lattice calculations suggests that these errors are not large.

AB - We calculate the vector form factor in K→πlν semileptonic decays at zero momentum transfer f+(0) from numerical simulations of two-flavor QCD on the lattice. Our simulations are carried out on 163×32 at a lattice spacing of 0.12fm using a combination of the DBW2 gauge and the domain-wall quark actions, which possesses excellent chiral symmetry even at finite lattice spacings. The size of fifth dimension is set to Ls=12, which leads to a residual quark mass of a few MeV. Through a set of double ratios of correlation functions, the form factor calculated on the lattice is accurately interpolated to zero momentum transfer, and then is extrapolated to the physical quark mass. We obtain f+(0)=0.968(9)(6), where the first error is statistical and the second is the systematic error due to the chiral extrapolation. Previous estimates based on a phenomenological model and chiral perturbation theory are consistent with our result. Combining with an average of the decay rate from recent experiments, our estimate of f+(0) leads to the Cabibbo-Kobayashi-Maskawa (CKM) matrix element |Vus|=0.2245(27), which is consistent with CKM unitarity. These estimates of f+(0) and |Vus| are subject to systematic uncertainties due to the finite lattice spacing and quenching of strange quarks, though nice consistency in f+(0) with previous lattice calculations suggests that these errors are not large.

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U2 - 10.1103/PhysRevD.74.114502

DO - 10.1103/PhysRevD.74.114502

M3 - Article

AN - SCOPUS:33845371338

VL - 74

JO - Physical Review D - Particles, Fields, Gravitation and Cosmology

JF - Physical Review D - Particles, Fields, Gravitation and Cosmology

SN - 1550-7998

IS - 11

M1 - 114502

ER -