Speaker
Description
Pion distribution amplitude (DA) describes the wave function of pion as a quark-antiquark pair in the infinite-momentum frame. It has rich phenomenology due to its universality as inputs to exclusive processes and form factors at large momentum transfer.
In this talk, I will present our recent lattice QCD calculation of pion DA on a chiral-symmetric domain-wall fermion ensemble at physical pion mass through the large momentum effective theory (LaMET) approach. I will discuss the theoretical improvements within the LaMET framework, especially the first application of threshold resummation in the perturbative matching onto the light-cone DA, which resums the large logarithms in the soft gluon limit at next-to-next-to-leading order. Applying the same analysis to data from a similar ensemble but with explicit chiral-breaking term, we find with 2σ confidence level that the DA obtained from chiral fermions is flatter and lower near x=0.5, with a larger second Mellin moment extracted through operator product expansion.
