2025/11/04 by Edoardo Spezzano, Spezzano, Edoardo, Tomáš Ježo +7
Computer Science · Physics and Astronomy · #Computational Physics and Python Applications #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2511.02407
openalex publication_date 2025/11/04 · openalex created_date 2025/11/06 · openalex updated_date 2026/07/28
We present next-to-leading-order (NLO) calculations of heavy-quark contributions to deep-inelastic scattering (DIS) structure functions F4 and F5 within the Aivazis--Collins--Olness--Tung (ACOT) scheme, implemented in the open source library APFEL++ using CT18NLO parton distribution functions. These structure functions, suppressed by lepton mass effects in light-lepton processes, become significant in muon, tau-lepton and neutrino scattering at facilities such as SHiP, IceCube, and DUNE. Our results reveal NLO corrections up to 10% relative to leading order, with pronounced heavy-quark effects at low Bjorken-x, impacting gluon and strange quark distributions. In the unpolarized case, F4/5γZ and F4/5γ do not contribute to the cross section, while the γZ interference becomes accessible with longitudinally polarized lepton beams at the Electron-Ion Collider (EIC), offering enhanced sensitivity at low Q2 due to reduced Z-boson propagator suppression. Analytical NLO expressions have also been derived for the polarized structure functions g1, g4, g5, g6, and g7 in the ACOT framework. These developments enable precise theoretical predictions for upcoming experimental programs and global QCD analyses.