Fant\^omas4QCD: pion PDFs with epistemic uncertainties

TL;DR

This paper presents a NLO QCD analysis of pion PDFs within the Fant extasciitildeomas4QCD framework, emphasizing the importance of epistemic uncertainties and parametrization dependence in hadron structure studies.

Contribution

It introduces a method to quantify epistemic uncertainties in pion PDFs and explores the anti-correlation between gluon and sea distributions.

Findings

Anti-correlation between gluon and sea distributions in pion PDFs

Sampling over parametrizations reveals significant epistemic uncertainties

Highlights the importance of accounting for epistemic uncertainties in QCD analyses

Abstract

In these proceedings, we reiterate and extend the discussion of the Next-to-Leading Order (NLO) QCD analysis of the charged pion Parton Distribution Function (PDF) obtained within the Fant\^omas4QCD framework. The goal of the Fant\^omas analysis is to quantify the dependence on the parametrization form in global QCD analyses, with a first application to the pion PDFs. We highlight the anti-correlation between the experimentally allowed gluon and sea distributions in the pion, as made apparent by the sampling over parametrization forms. This result, for the sea and gluon sector, illustrates the importance of accounting for epistemic uncertainties in data-driven QCD analyses. In that regard, we further discuss the meaning of the sampling uncertainty and why it is key in phenomenological studies of hadron structure.