An analysis of parton distributions in a pion with Bézier parametrizations

Abstract

We explore the role of parametrizations for nonperturbative QCD functions in global analyses, with a specific application to extending a phenomenological analysis of the parton distribution functions (PDFs) in the charged pion realized in the xFitter fitting framework. The parametrization dependence of PDFs in our pion fits substantially enlarges the uncertainties from the experimental sources estimated in the previous analyses. We systematically explore the parametrization dependence by employing a novel technique to automate generation of polynomial parametrizations for PDFs that makes use of Bézier curves. This technique is implemented in a C++ module Fantômas that is included in the xFitter program. Our analysis reveals that the sea and gluon distributions in the pion are not well disentangled, even when considering measurements in leading-neutron deep inelastic scattering. For example, the pion PDF solutions with a vanishing gluon and large quark sea are still experimentally allowed, which elevates the importance of ongoing lattice and nonperturbative QCD calculations, together with the planned pion scattering experiments, for conclusive studies of the pion structure.

arXiv comment22 pages, 15 figures

References in corpus (60)

• New Generation of Parton Distributions with Uncertainties from Global QCD Analysis
• LHAPDF6: parton density access in the LHC precision era
• Parton Physics on Euclidean Lattice
• New CTEQ global analysis of quantum chromodynamics with high-precision data from the LHC
• A first unbiased global NLO determination of parton distributions and their uncertainties
• Uncertainties of predictions from parton distribution functions II: the Hessian method
• QCDNUM: Fast QCD Evolution and Convolution
• Large-Momentum Effective Theory
• Pionic Parton Distributions Revisited
• Soft-Gluon Resummation and the Valence Parton Distribution Function of the Pion
• A Variable-Flavour Number Scheme for NNLO
• The PDF4LHC21 combination of global PDF fits for the LHC Run III
• Pion and Kaon Structure at the Electron-Ion Collider
• First Monte Carlo global QCD analysis of pion parton distributions
• Pion Valence Quark Distribution from Matrix Element Calculated in Lattice QCD
• Gluon gravitational form factors of the nucleon and the pion from lattice QCD
• A meta-analysis of parton distribution functions
• Pion Valence Structure from Ioffe Time Pseudo-Distributions
• Multivariate Fitting and the Error Matrix in Global Analysis of Data
• Shape of Pion Distribution Amplitude
• First direct lattice-QCD calculation of the $x$-dependence of the pion parton distribution function
• Pion and photon light-cone wave functions from the instanton vacuum
• First extraction of valence transversities in a collinear framework
• Valence parton distribution function of pion from fine lattice
• Parton Distribution Functions of the Charged Pion Within The xFitter Framework
• On the Pion Distribution Amplitude Shape
• Valence parton distribution of pion from lattice QCD: Approaching continuum
• Hadron structure in high-energy collisions
• Leading neutron production in $e^{+}p$ collisions at HERA
• Pion valence quark distribution from current-current correlation in lattice QCD
• Measurement of Leading Neutron Production in Deep-Inelastic Scattering at HERA
• Pion light-cone wave function and pion distribution amplitude in the Nambu-Jona-Lasinio model
• One-loop evolution of parton pseudo-distribution functions on the lattice
• The asymptotic behaviour of parton distributions at small and large $x$
• Inelastic Production of J/psi Mesons in Photoproduction and Deep Inelastic Scattering at HERA
• Gluon Pseudo-Distributions at Short Distances: Forward Case
• Continuum-extrapolated NNLO Valence PDF of Pion at the Physical Point
• Pion structure function from leading neutron electroproduction and SU(2) flavor asymmetry
• Reconstruction of Monte Carlo replicas from Hessian parton distributions
• Non-perturbative Pion Matrix Element of a twist-2 operator from the Lattice
• Gluon contributions to the pion mass and light cone momentum fraction
• Leading Power Accuracy in Lattice Calculations of Parton Distributions
• The valence quark, sea, and gluon content of the pion from the parton distribution functions and the electromagnetic form factor
• The pion transition form factor and the pion distribution amplitude
• The pion and kaon $⟨x^3⟩$ from lattice QCD and PDF reconstruction from Mellin moments
• Proton and pion distribution functions in counterpoint
• Precision Control in Lattice Calculation of $x$-dependent Pion Distribution Amplitude
• Positivity and renormalization of parton densities
• Testing momentum dependence of the nonperturbative hadron structure in a global QCD analysis
• Towards the three-dimensional parton structure of the pion: Integrating transverse momentum data into global QCD analysis
• Complementarity of experimental and lattice QCD data on pion parton distributions
• Parton distributions need representative sampling
• Constrained fit of the valence transversity distributions from dihadron production
• The Mellin moments $⟨x⟩$ and $⟨x^2⟩$ for the pion and kaon from lattice QCD
• Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab
• The case for an EIC Theory Alliance: Theoretical Challenges of the EIC
• Light quark and antiquark constraints from new electroweak data
• On the positivity of MSbar parton distributions
• The Gluon Moment and Parton Distribution Function of the Pion from $N_f=2+1+1$ Lattice QCD
• Fantômas For QCD: parton distributions in a pion with Bézier parametrizations