Clarify higher-order corrections for CMS dijet data in proton-lead collisions

Clarify the impact of NNLO QCD corrections on the description of the CMS Run-I dijet measurements in proton-proton and proton-lead collisions before incorporating the data into future nCTEQ nuclear PDF analyses.

Background

CMS dijet data probe nuclear PDFs over an intermediate- to large-x range and could provide important constraints on the gluon distribution. However, the absolute proton-proton and proton-lead distributions are poorly described at NLO, especially in the forward region, even though their ratios are broadly compatible with existing nPDF determinations.

The authors therefore exclude these data from nCTEQ26 and defer their inclusion until the effect of NNLO corrections is established.

References

The CMS dijet data and in particular the $p$Pb/$pp$ ratios will therefore only be considered for inclusion in future nCTEQ analyses, when the impact of NNLO corrections {Chen:2022tpk} has been clarified.

— nCTEQ26 nuclear parton distribution functions  (2610.13633 - Collaboration et al., 9 Oct 2026) in Section 10.2, subsection “CMS dijets”