K+K+scattering length from lattice QCD

Abstract

The ${K}^{+}{K}^{+}$ scattering length is calculated in fully-dynamical lattice QCD with domain-wall valence quarks on the MILC asqtad-improved gauge configurations with rooted-staggered sea quarks. Three-flavor mixed-action chiral perturbation theory at next-to-leading order, which includes the leading effects of the finite lattice spacing, is used to extrapolate the results of the lattice calculation to the physical value of ${m}_{{K}^{+}}/{f}_{{K}^{+}}$. We find ${m}_{{K}^{+}}{a}_{{K}^{+}{K}^{+}}=\ensuremath{-}0.352\ifmmode\pm\else\textpm\fi{}0.016$, where the statistical and systematic errors have been combined in quadrature.