A New Extraction of Pion Parton Distributions in the Statistical Model

TL;DR

This paper introduces a refined statistical model approach to extract pion parton distribution functions, reducing parameters and accurately fitting Drell-Yan data, demonstrating the model's predictive power.

Contribution

It adapts the statistical model for nucleons to pions, incorporating spin-0 and symmetry considerations, resulting in fewer parameters and improved data description.

Findings

Successful fit to $\pi^-$-induced Drell-Yan data using NLO QCD

Good agreement with $\pi^+/\pi^-$ Drell-Yan cross section ratios

Reduced parameter set enhances model predictiveness

Abstract

We present a new analysis to extract pion's parton distribution functions (PDFs) in the framework of the statistical model. Starting from the statistical model framework first developed for the spin-1/2 nucleon, we apply appropriate modifications taking into account the spin-0 nature of pion and the isospin and charge-conjugation symmetry properties. This results in a significant reduction of the number of parameters compared to a recent work to extract pion's PDFs. Using $\pi^-$-induced Drell-Yan data to determine the parameters of this statistical model approach, we show that a good description of these experimental data with Next-to-Leading order QCD calculations can be obtained. Good agreement between the calculations and the $\pi^+/\pi^-$ Drell-Yan cross section ratio data, not included in the global fit, has confirmed the predictive power of these new pion PDFs.