Light-cone distribution amplitudes of pseudoscalar mesons from lattice QCD

We present the first lattice determination of the two lowest Gegenbauer moments of the leading-twist pion and kaon light-cone distribution amplitudes with full control of all errors: $$ {a}_2^{\pi }={0.101}_{-24}^{+24} $$ for the pion; $$ {a}_1^K={0.0533}_{-35}^{+34} $$ and $$ {a}_2^K={0.090}_{-20}^{+19} $$ for the kaon. The calculation is carried out on 35 different CLS ensembles with Nf = 2 + 1 flavors of dynamical Wilson-clover fermions. These cover a multitude of pion and kaon mass combinations (including the physical point) and 5 different lattice spacings down to a = 0.039 fm. The momentum smearing technique and a new operator basis are employed to reduce statistical fluctuations and to improve the overlap with the ground states. The results are obtained from a combined chiral and continuum limit extrapolation that includes three separate trajectories in the quark mass plane.