Pion and kaon distribution amplitudes in the continuum limit

Meson distribution amplitudes (DAs)  hold the key to understanding how light-quark hadron masses emerge from QCD. Meson DAs are also important inputs in many hard exclusive processes at large momentum transfers. In this work, we present a lattice-QCD calculation of the pion, kaon and η_s distribution amplitudes using large-momentum effective theory (LaMET). The calculation is carried out on three lattice ensembles with 2+1+1 flavors of highly improved staggered quarks (HISQ), generated by MILC collaboration, at 310-MeV pion mass with 0.06, 0.09 and 0.12 fm lattice spacings. The resulting lattice matrix elements are renormalized in a hybrid scheme to cancel the linear divergence introduced by the Wilson line without introducing extra non-perturbative effects at large distance, thus a perturbative matching to MS bar scheme is valid. The renormalized matrix elements are extrapolated to the continuum, and then, with a modeling of the longtail, are inverse Fourier transformed to momentum space. The x-dependence of the DA is then extracted through the inverse perturbative matching.