CT25: Progress toward next-generation PDFs for precision phenomenology at the LHC

TL;DR

This paper reports progress on the development of the CT25 parton distribution functions, incorporating new LHC data and advanced analysis techniques to improve precision in high-energy physics predictions at the LHC.

Contribution

It introduces the baseline fit for CT25 PDFs, integrating recent LHC data and exploring the interplay with lattice-QCD, alpha_s extraction, and uncertainty quantification methods.

Findings

New LHC data significantly influence high-x gluon and quark sea distributions.

Progress in understanding the impact of N$^3$LO corrections on PDF fits.

Enhanced uncertainty quantification including parametrization dependence.

Abstract

We summarize recent progress toward the next generation of CTEQ-TEA parton distribution functions, CT25, based on a global NNLO analysis that incorporates a significant sample of newly included LHC data. We present a baseline fit within the forthcoming full CT25 fit, which includes new Drell-Yan, top-pair, and inclusive-jet data at 8 and 13 TeV, and exhibits non-trivial pulls on the high-$x$ gluon and the flavor structure of the quark sea. In the context of progress toward CT25, we also summarize several recent and ongoing studies of the interplay between phenomenological PDFs and lattice-QCD calculations, simultaneous extractions of $\alpha_s(M_Z)$ within the CT framework, and an expanded program of uncertainty quantification that treats parametrization dependence as an explicit source of epistemic uncertainty, among other issues. We also briefly highlight CT efforts to understand the effects of partial implementations of N$^3$LO corrections into PDF fits, which include benchmark calculations for Higgs and vector-boson processes. We comment on the implications of recent improvements to the CT analysis for precision phenomenology at the LHC and future facilities.