Pion distribution amplitude from Euclidean correlation functions

TL;DR

This paper explores a lattice QCD method using Euclidean correlation functions and momentum smearing to calculate the pion distribution amplitude, offering an alternative to traditional approaches and addressing operator mixing issues.

Contribution

It introduces a novel lattice technique employing Euclidean correlation functions and momentum smearing to determine the pion distribution amplitude, avoiding operator mixing.

Findings

Feasibility demonstrated for calculating pion DA from Euclidean correlators.

Method is complementary to existing approaches based on moments and quasi-distributions.

Highlights similarities and differences between the new method and quasi-distribution techniques.

Abstract

Following the proposal in [1], we study the feasibility to calculate the pion distribution amplitude (DA) from suitably chosen Euclidean correlation functions at large momentum. In our lattice study we employ the novel momentum smearing technique [2,3]. This approach is complementary to the calculations of the lowest moments of the DA using the Wilson operator product expansion and avoids mixing with lower dimensional local operators on the lattice. The theoretical status of this method is similar to that of quasi-distributions [4], which has recently been applied to the same problem in [5]. The similarities and differences between these two techniques are highlighted.