PDF4LHC21: Update on the benchmarking of the CT, MSHT and NNPDF global PDF fits

TL;DR

This paper updates and benchmarks the latest global parton distribution functions (PDFs) from CT, MSHT, and NNPDF groups, highlighting their differences and similarities after incorporating new LHC data, to improve LHC physics analyses.

Contribution

It provides a comprehensive benchmarking comparison of the updated CT18, MSHT20, and NNPDF3.1 PDFs, resulting in a new combined PDF4LHC21 ensemble for LHC applications.

Findings

Identified key differences and similarities among the three PDF sets.

Developed a new combined PDF4LHC21 ensemble.

Enhanced understanding of PDFs with recent LHC data.

Abstract

There have been recent updates to the three global PDF fits (CT, MSHT and NNPDF), all adding large amounts of data from the LHC, and this has resulted in significant changes to the global PDFs. Given the impact that the new PDFs will have on physics comparisons at the LHC, it is crucial to perform a benchmarking among the PDFs, similar in spirit to that which was carried out for PDF4LHC15, widely used for LHC physics. In this article we detail a benchmarking comparison of three global PDF sets - CT18, MSHT20 and NNPDF3.1 - and their similarities and differences that have been observed. The end result of this study will be a new PDF4LHC21 ensemble of combined PDFs suitable for a wide range of LHC applications.