Toward N3LO CT global PDF analyses: The SACOT-χ scheme in DIS and DGLAP evolution at partial N3LO
Abstract
We discuss three aspects of the ongoing efforts of the CTEQ--TEA group toward global parton distribution function (PDF) analyses beyond NNLO accuracy in QCD. First, we present a realization of the SACOT-χ general-mass variable flavor number scheme for deep-inelastic scattering (DIS) at the partial next-to-next-to-next-to-leading order (pN3LO) in QCD. We numerically illustrate how this SACOT-χ theory prediction captures the dependence of DIS structure functions on masses of heavy quarks with inclusion of the available O(αs3) contributions. Second, we discuss a preliminary pN3LO CT25 fit that implements such contributions. Third, we extend the Candia algorithm for solving DGLAP evolution equations for unpolarized parton distribution functions (PDFs) in x space to N3LO in QCD. The algorithm is based on logarithmic expansions of the solution and can be extended to all orders in QCD. An expansion equivalent to the exact DGLAP solution at N3LO is presented in the non-singlet sector. We show results for approximate N3LO PDFs evolved using the most recent approximations to the 4-loop splitting functions in QCD.
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BibTeX
@misc{guzzi2026toward,
title = {{Toward N$^3$LO CT global PDF analyses: The SACOT-$χ$ scheme in DIS and DGLAP evolution at partial N$^3$LO}},
author = {Marco Guzzi and Yao Fu and Casey Hampson and Pavel Nadolsky and Maximiliano Ponce-Chavez and Tanishq Sharma and Keping Xie and C. -P. Yuan},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.07233},
eprint = {2610.07233},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.07233},
}
RIS
TY - UNPB
TI - Toward N^3LO CT global PDF analyses: The SACOT-χ scheme in DIS and DGLAP evolution at partial N^3LO
AU - Marco Guzzi
AU - Yao Fu
AU - Casey Hampson
AU - Pavel Nadolsky
AU - Maximiliano Ponce-Chavez
AU - Tanishq Sharma
AU - Keping Xie
AU - C. -P. Yuan
PY - 2026
DA - 2026/10/05
PB - arXiv
DO - 10.48550/arxiv.2610.07233
UR - https://arxiv.org/abs/2610.07233
AB - We discuss three aspects of the ongoing efforts of the CTEQ--TEA group toward global parton distribution function (PDF) analyses beyond NNLO accuracy in QCD. First, we present a realization of the SACOT-χ general-mass variable flavor number scheme for deep-inelastic scattering (DIS) at the partial next-to-next-to-next-to-leading order (pN^3LO) in QCD. We numerically illustrate how this SACOT-χ theory prediction captures the dependence of DIS structure functions on masses of heavy quarks with inclusion of the available O(α_s^3) contributions. Second, we discuss a preliminary pN^3LO CT25 fit that implements such contributions. Third, we extend the Candia algorithm for solving DGLAP evolution equations for unpolarized parton distribution functions (PDFs) in x space to N^3LO in QCD. The algorithm is based on logarithmic expansions of the solution and can be extended to all orders in QCD. An expansion equivalent to the exact DGLAP solution at N^3LO is presented in the non-singlet sector. We show results for approximate N^3LO PDFs evolved using the most recent approximations to the 4-loop splitting functions in QCD.
ER -