title: Kaon B parameter from improved staggered fermions in N(f)=2+1 QCD.
abstract: We present a calculation of the kaon B parameter B(K) using lattice QCD. We use improved staggered valence and sea fermions, the latter generated by the MILC Collaboration with N(f)=2+1 light flavors. To control discretization errors, we use four different lattice spacings ranging down to a≈0.045 fm. The chiral and continuum extrapolations are done using SU(2) staggered chiral perturbation theory. Our final result is B(K)=0.727±0.004(stat)±0.038(syst), where the dominant systematic error is from our use of truncated (one-loop) matching factors.
authors.affiliation: Korea Institute of Science and Technology Information, Daejeon, 305-806, South Korea.
authors.forename: Taegil
authors.initials: T
authors.lastname: Bae
authors.forename: Yong-Chull
authors.initials: YC
authors.lastname: Jang
authors.forename: Chulwoo
authors.initials: C
authors.lastname: Jung
authors.forename: Hyung-Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Jangho
authors.initials: J
authors.lastname: Kim
authors.forename: Jongjeong
authors.initials: J
authors.lastname: Kim
authors.forename: Kwangwoo
authors.initials: K
authors.lastname: Kim
authors.forename: Sunghee
authors.initials: S
authors.lastname: Kim
authors.forename: Weonjong
authors.initials: W
authors.lastname: Lee
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Sharpe
authors.forename: Boram
authors.initials: B
authors.lastname: Yoon