Kaon Distribution Amplitude from Lattice QCD and the Flavor SU(3) Symmetry

Abstract We present the first lattice-QCDcalculation of the kaon distribution amplitude using the large-momentum effective theory (LaMET) approach. The momentum-smearing technique has been implemented to improve signals at large meson momenta. We subtract the power divergence due to Wilson line to high precision using multiple lattice spacings. The kaon structure clearly shows an asymmetry of the distribution amplitude around x = 1 / 2 , a clear sign of its skewness. Our result also prefers a broader distribution than the asymptotic form. We also study the leading SU(3) flavor symmetry breaking relations for the pion, kaon and eta mesondistribution amplitudes, and the results are consistent with the prediction from chiral perturbation theory.