Global QCD Analysis of Pion Parton Distributions with Threshold Resummation

We perform the first global QCD analysis of pion valence, sea quark, and gluon distributions within a Bayesian Monte Carlo framework with threshold resummation on Drell-Yan cross sections at next-toleading log accuracy. Exploring various treatments of resummation, we find that the large-x asymptotics of the valence quark distribution similar to(1 - x)flv can differ significantly, with flv ranging from approximate to 1 to > 2.5 at the input scale. Regardless of the specific implementation, however, the resummation induced redistribution of the momentum between valence quarks and gluons boosts the total momentum carried by gluons to approximate to 40%, increasing the gluon contribution to the pion mass to approximate to 40 MeV.