Gluon gravitational form factors of the proton in a light-front spectator model

Abstract

We calculate the gluon gravitational form factors (GFFs) of the proton using a light-front spectator model based on soft-wall AdS/QCD, where the active parton is a gluon. The model parameters are determined by fitting the unpolarized gluon distribution function to the NNPDF3.0nlo dataset. Subsequently, we predict the polarized gluon distribution, finding consistency with global analyses. Our predictions for the gluon GFFs show good agreement with recent lattice QCD simulations and experimental extractions. Using these gluon GFFs, we compute the contribution of the gluon to the proton mass and mechanical radii. We also analyze the gluonic contribution to the two-dimensional Galilean densities, including energy density, radial and tangential pressure, isotropic pressure, and pressure anisotropy of the proton.