Pion Distribution Amplitudes in the Continuum Limit

TL;DR

This paper reports a lattice-QCD calculation of pion distribution amplitudes using LaMET, employing multiple ensembles and nonperturbative renormalization to approach the continuum limit, providing insights into the pion's internal structure.

Contribution

It introduces a novel lattice-QCD approach to determine pion distribution amplitudes in the continuum limit using LaMET and multiple ensembles with nonperturbative renormalization.

Findings

Consistent pion distribution amplitudes obtained across different lattice spacings.

Demonstrated the effectiveness of LaMET in extracting x-dependence.

Provided continuum-extrapolated results for pion structure.

Abstract

We present a lattice-QCD calculation of the pion distribution amplitudes using large-momentum effective theory (LaMET). Our calculation is carried out using five ensembles with 2+1+1 flavors of highly improved staggered quarks (HISQ), generated by MILC collaboration, at 310 MeV and 220 MeV pion mass with 0.06, 0.09, 0.12 and 0.15 fm lattice spacings. We use clover fermion action for the valence quarks and tune the quark mass to match the lightest light and strange masses in the sea. The resulting lattice matrix elements are nonperturbatively renormalized in regularization-independent momentum-subtraction (RI/MOM) scheme and extrapolated to the continuum. We compare different approaches to extract the x-dependence of the pion distribution amplitudes.