title: Soft-gluon resummation and the valence parton distribution function of the pion.
abstract: We determine the valence parton distribution function of the pion by performing a new analysis of data for the Drell-Yan process π- N → μ+ μ- X. Compared to previous analyses, we include next-to-leading-logarithmic threshold resummation effects in the calculation of the Drell-Yan cross section. As a result of these, we find a considerably softer valence distribution at high momentum fractions x than obtained in previous next-to-leading-order analyses, in line with expectations based on perturbative-QCD counting rules or Dyson-Schwinger equations.
authors.affiliation: Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Aicher
authors.forename: Andreas
authors.initials: A
authors.lastname: Schäfer
authors.forename: Werner
authors.initials: W
authors.lastname: Vogelsang