First Monte Carlo Global QCD Analysis of Pion Parton Distributions
Journal
Physical Review Letters
Journal Volume
121
Journal Issue
15
Date Issued
2018
Author(s)
Abstract
We perform the first global QCD analysis of parton distribution functions (PDFs) in the pion, combining πA Drell-Yan data with leading neutron electroproduction from HERA within a Monte Carlo approach based on nested sampling. Inclusion of the HERA data allows the pion PDFs to be determined down to much lower values of x, with relatively weak model dependence from uncertainties in the chiral splitting function. The combined analysis reveals that gluons carry a significantly higher pion momentum fraction, ?30%, than that inferred from Drell-Yan data alone, with sea quarks carrying a somewhat smaller fraction, ?15%, at the input scale. Within the same effective theory framework, the chiral splitting function and pion PDFs can be used to describe the d-? asymmetry in the proton. ? 2018 authors.
Subjects
Distribution functions; Monte Carlo methods; Combined analysis; Effective theories; Electroproduction; Momentum fraction; Monte Carlo approach; Parton distribution functions; Parton distributions; Weak models; Hadrons
Type
journal article