Neutral kaon mixing parameter BK from unquenched mixed-action lattice QCD

作者：Aubin C^*; Laiho Jack; Van de Water Ruth S

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2010, 81(1): 014507.

DOI：10.1103/PhysRevD.81.014507

We calculate the neutral kaon mixing parameter B-K in unquenched lattice QCD using asqtad-improved staggered sea quarks and domain-wall valence quarks. We use the "2 + 1'' flavor gauge configurations generated by the MILC Collaboration, and simulate with multiple valence and sea-quark masses at two lattice spacings of a approximate to 0.12 fm and a approximate to 0.09 fm. We match the lattice determination of B-K to the continuum value using the nonperturbative method of Rome-Southampton, and extrapolate B-K to the continuum and physical quark masses using mixed-action chiral perturbation theory. The "mixed-action'' method enables us to control all sources of systematic uncertainty and therefore to precisely determine B-K; we find a value of B-K((MS) over bar ,NDR)(2 GeV) = 0.527(6)(21), where the first error is statistical and the second is systematic.

• 出版日期2010-1