Pseudoscalar decay constants, light-quark masses, and BK from mixed-action lattice QCD

John W Laiho, Ruth S. Van de Water

Research output: Contribution to journalConference article

3 Scopus citations

Abstract

We present updated results for the leptonic decay constants fπ and fK, the light u, d, and s-quark masses, and the neutral kaon mixing parameter BK from mixed-action lattice simulations with staggered sea quarks and domain-wall valence quarks. We use the publicly-available 2+1 flavor MILC asqtad-improved staggered gauge configurations with multiple light sea-quark masses and three lattice spacings, and compute the kaon mixing matrix element with several partially-quenched valence-quark masses. We then extrapolate to the physical light-quark masses and the continuum using partially-quenched chiral perturbation theory formulated for mixed-action lattice simulations. For BK we match the lattice four-fermion operator to the continuum using the nonperturbative method of Rome-Southampton. Our new results benefit from two significant improvements over our published work: (1) we have added a third lattice spacing of a≈0.06 fm to better control the continuum extrapolation, and (2) we have implemented a new lattice renormalization scheme (the RI/SMOMγµ scheme developed by Sturm et al.) that suppresses chiral-symmetry breaking and other infrared effects and, in practice, also shrinks the size of the 1-loop perturbative coefficient needed to match to the continuum MS scheme. When combined with the use of volume-averaged momentum sources and twisted-boundary conditions, this significantly reduces the systematic uncertainty in the renormalization factor ZBK

Original languageEnglish (US)
JournalProceedings of Science
Volume139
StatePublished - Jan 1 2011
Externally publishedYes
Event29th International Symposium on Lattice Field Theory, Lattice 2011 - Squaw Valley, Lake Tahoe, United States
Duration: Jul 10 2011Jul 16 2011

ASJC Scopus subject areas

  • General

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