# Pion Distribution Amplitude from Lattice QCD

## TL;DR

This paper reports the first lattice QCD calculation of the pion distribution amplitude using LaMET, including mass corrections and Wilson-line renormalization, revealing a broader single-hump shape at 310 MeV.

## Contribution

It introduces a novel lattice QCD method to compute the pion distribution amplitude with all-order mass corrections and renormalization techniques.

## Key findings

- Broader single-hump pion distribution amplitude observed.
- Mass corrections calculated to all orders in m_pi^2/P_z^2.
- Wilson-line renormalization reduces endpoint oscillations.

## Abstract

We present the first lattice-QCD calculation of the pion distribution amplitude using the large- momentum effective field theory (LaMET) approach, which allows us to extract lightcone parton observables from a Euclidean lattice. The mass corrections needed to extract the pion distribution amplitude from this approach are calculated to all orders in $m^2_{\pi} /P_z^2$. We also implement the Wilson- line renormalization which is crucial to remove the power divergences in this approach, and find that it reduces the oscillation at the end points of the distribution amplitude. Our exploratory result at 310-MeV pion mass favors a single-hump form broader than the asymptotic form of the pion distribution amplitude.