The light-cone distribution amplitude (LCDA) of the pion carries information about the parton momentum distribution and is an important theoretical input into various predictions of exclusive measurements at high energy, including the pion electromagnetic form factor. This talk presents progress towards a lattice calculation of the fourth Mellin moment of the LCDA using the heavy quark...
Calculating the $x$-dependence of pion distribution amplitude (DA) using the large-momentum effective theory has entered the era where the systematics need to be controlled. We demonstrate the necessity of a proper renormalization and a corresponding perturbative matching to achieve power accuracy ~$O(\Lambda_{QCD}/xP_z)$. By resumming the leading renormalon in the perturbative series, we are...
I will present the recent calculations of gluonic matrix elements related to the nucleon's unpolarized and helicity gluon PDF. Gluon matrix elements are notoriously noisy. By leveraging the tools of distillation and summed GEVP, HadStruc has reach a necessary precision to compare results to phenomenological determinations of gluon structure. Recently, doubt has been given to the applicability...
We present the first physical-continuum limit $x$-dependent nucleon gluon distribution from lattice QCD using the pseudo-PDF approach, on lattice ensembles with $2+1+1$ flavors of highly improved staggered quarks (HISQ), generated by MILC Collaboration. We use clover fermions for the valence action on three lattice spacings $a \approx 0.9$, 0.12 and 0.15~fm and three pion masses $M_\pi \approx...
We present results of the x-dependence of the unpolarized gluon PDF for the proton. We use an Nf = 2 + 1 + 1 ensemble of maximally twisted mass fermions with clover improvement and the Iwasaki improved gluon action. The quark masses are tuned so that the pion mass is 260 MeV. We use a 32^3 × 64 lattice size with a lattice spacing a = 0.093 fm giving a spatial extent of 3 fm. We employ the...
