Low-$Q^{2}$ nucleon structure from an infrared-safe evolution scheme

TL;DR

This paper presents a nonperturbative approach to modeling low-$Q^2$ nucleon structure using an infrared-safe evolution scheme, aligning well with experimental data and highlighting the dominance of valence quarks at hadronic scales.

Contribution

It introduces an all-order infrared-safe evolution scheme that effectively connects nonperturbative and perturbative nucleon structures from a simple valence quark input.

Findings

Resonance peaks in $F_2$ are modulated by valence quark distributions.

Valence quarks dominate PDFs at the hadronic scale.

High-twist corrections are necessary at low $Q^2$.

Abstract

The low-$Q^2$ nucleon structure is given with a simple nonperturbative input of three valence quarks and an all-order infrared-safe evolution scheme, showing some consistences with the experimental data. The resonance peaks in the experimental data of $F_2$ structure function are found to be modulated by the valence quark distributions. With little sea quark distribution at low $Q^2$ the valence-quark bump is clearly shown in the structure function. The three valence quark distributions at the hadronic scale is found to be the dominant origin of the PDFs at the hard scales. The high-twist corrections are needed to explain the sizeable discrepancy between the theory and the experimental measurements at low $Q^2$. The infrared-safe evolution scheme is a powerful tool for connecting the nucleon structures in the nonperturbative and perturbative regions.