Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2610.07233

Toward N$^3$LO CT global PDF analyses: The SACOT-$χ$ scheme in DIS and DGLAP evolution at partial N$^3$LO

Marco Guzzi·Yao Fu·Casey Hampson·Pavel Nadolsky·Maximiliano Ponce-Chavez·Tanishq Sharma·Keping Xie·C. -P. Yuan
View original source ↗Read source document ↗Export metadata ↓

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 (pN$^3$LO) 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$^3$LO 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$^3$LO 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$^3$LO is presented in the non-singlet sector. We show results for approximate N$^3$LO PDFs evolved using the most recent approximations to the 4-loop splitting functions in QCD.

Explore related subjects

hep-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Marco Guzzi, Yao Fu, Casey Hampson, Pavel Nadolsky, Maximiliano Ponce-Chavez, Tanishq Sharma, Keping Xie, C. -P. Yuan. 2026-10-05. Toward N$^3$LO CT global PDF analyses: The SACOT-$χ$ scheme in DIS and DGLAP evolution at partial N$^3$LO. https://arxiv.org/abs/2610.07233

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Decoding Weak Phase Amplitudes in Charmed Baryon Decays

In this Letter, we present a strategy to decode decay amplitudes with different weak phases in two-body charmed baryon decays, addressing a long-standing challenge to understanding CP violation in this sector. Using SU(3) flavor symmetry, we disentangle the amplitudes defined through $M=λ_s A_s + λ_b A_b$ ($λ_i = V_{ui}V_{ci}^*$), enabling a data-driven determination of their relative hierarchy across Cabibbo-favored, singly, and doubly Cabibbo-suppressed modes. Applying this framework to current data, we find that the ratio $A_b/A_s$ is approximately 100 times larger than expectation of $\mathcal{O}(1)$ at $2.1σ$ level. This unexpected pattern may be accommodated by SU(3) breaking effects, but it can also point to new physics. We further show that the Lee-Yang parameters provide an independent and complementary probe. To resolve this ambiguity in the origin of the enhancement, we propose a decisive discriminator using decay modes insensitive to large SU(3) breaking, in particular $Ξ_c^0 \to pK^-$ and $Ξ_c^0 \to Σ^+π^-$ as golden channels. Measurements of these modes will distinguish between symmetry breaking effects and new physics, establishing a clean pathway to probe CP violation in the charm baryon sector.

hep-ph↗
arXiv2026

Next-to-next-to-next-to-leading order QCD corrections to photon-pair production

The production of two isolated photons at the Large Hadron Collider has applications in Higgs-boson phenomenology and in new-physics searches. In fact, measurements would provide more insight if a percent-level theoretical prediction were available. We account for next-to-next-to-next-to-leading order strong-interaction effects in the cross section for the first time. This is not only necessary to demonstrate the convergence of perturbation theory, but also results in a reduction of the theoretical uncertainty by a factor of three down to 3\%. With this, we pave the way to improved analyses.

hep-ph↗
arXiv2026

Charmonium production at SPS and FAIR energies

In this study we apply the Remler formalism to charmonium production at SPS and GSI/FAIR energies in order to investigate the effects of baryon-rich matter on charmonium production and dissociation in heavy-ion collisions within the Parton-Hadron-String Dynamics (PHSD). As a first step the Remler formalism is tested in p+p collisions and then applied to p+A collisions in order to extract the nuclear absorption cross section of charmonium, which is then utilized in heavy-ion collisions. We find that the Remler formalism successfully describes charmonium production in heavy-ion collisions at SPS energies when an in-medium heavy quark potential is implemented, in which $J/ψ$ dissociates near $T_c$. Finally the same formalism is applied to the low CERN/SPS energy and GSI/FAIR energies, where we estimate charmonium production.

hep-ph↗