2024/10/16 by Xiangdong Ji, Ji, Xiangdong, Yizhuang Liu +5 · 1 citation
Computer Science · Physics and Astronomy · #Advanced Data Storage Technologies #FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2410.12910
openalex publication_date 2024/10/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Parton distribution functions (PDFs) at large x are challenging to extract from experimental data, yet they are essential for understanding hadron structure and searching for new physics beyond the Standard Model. Within the framework of the large momentum Pz expansion of lattice quasi-PDFs, we investigate large x PDFs, where the matching coefficient is factorized into the hard kernel, related to the active quark momentum x Pz, and the threshold soft function, associated with the spectator momentum (1-x) Pz. The renormalization group equation of the soft function enables the resummation of the threshold double logarithms αk ln2k(1-x), which is crucial for a reliable and controllable calculation of large x PDFs. Our analysis with pion valence PDFs indicates that perturbative matching breaks down when the spectator momentum (1-x)Pz approaches Λ\rm QCD, but remains valid when both x Pz and (1-x)Pz are much larger than Λ\rm QCD. Additionally, we incorporate leading renormalon resummation within the threshold framework, demonstrating good perturbative convergence in the region where both spectator and active quark momenta are perturbative scales.