The K+K+ Scattering Length from Lattice QCD

TL;DR

This paper computes the K+K+ scattering length using lattice QCD with mixed-action chiral perturbation theory, providing a precise estimate that includes finite lattice spacing effects.

Contribution

It presents the first fully-dynamical lattice QCD calculation of the K+K+ scattering length with chiral extrapolation including lattice spacing effects.

Findings

m_{K+} a_{K+K+} = -0.352 +- 0.016

Results are extrapolated to the physical point using next-to-leading order chiral perturbation theory

The calculation accounts for statistical and systematic uncertainties

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+} = -0.352 +- 0.016, where the statistical and systematic errors have been combined in quadrature.