Speaker
Description
In this talk, we report our recent lattice QCD calculations of transverse-momentum-dependent parton distribution functions (TMDPDFs) for pion and proton using the Coulomb-gauge quasi-TMD framework. For the pion, we determine the valence-quark TMDPDF along with the intrinsic soft function and Collins–Soper kernel, showing consistency with perturbation theory at short transverse separations and with phenomenological fits at moderate momentum fractions. For the proton, we report the first lattice results of isovector helicity and flavor-dependent unpolarized TMDPDFs at physical quark masses using domain-wall fermions. Scale-independent ratios allow direct comparison with global fits, revealing similar helicity and unpolarized distributions at moderate x and only mild flavor dependence. These studies demonstrate the practicality of the Coulomb-gauge approach and provide nonperturbative benchmarks for global analyses and future experiments at the EIC.
