CTEQ-TEA parton distribution functions and HERA Run I and II combined data

TL;DR

This paper updates the CT14 parton distribution functions by incorporating the combined HERA I+II deep inelastic scattering data, resulting in new PDFs called CT14_HERA2, which fit the data well and are consistent with previous PDFs.

Contribution

The paper introduces CT14_HERA2 PDFs obtained by refitting CT14 with the combined HERA I+II data, demonstrating compatibility and improved data description.

Findings

HERA I+II data can be fit well by the new PDFs.

CT14 and CT14_HERA2 PDFs agree within errors.

Both PDFs describe non-HERA data equally well.

Abstract

We analyze the impact of the recent HERA run I+II combination of inclusive deep inelastic scattering cross-section data on the CT14 global analysis of PDFs. New PDFs at NLO and NNLO, called CT14$_{\textrm{HERA2}}$, are obtained by a refit of the CT14 data ensembles, in which the HERA run I combined measurements are replaced by the new HERA run I+II combination. The CT14 functional parametrization of PDFs is flexible enough to allow good descriptions of different flavor combinations, so we use the same parametrization for CT14$_{\textrm{HERA2}}$ but with an additional shape parameter for describing the strange quark PDF. We find that the HERA I+II data can be fit reasonably well, and both CT14 and CT14$_{\textrm{HERA2}}$ PDFs can describe equally well the non-HERA data included in our global analysis. Because the CT14 and CT14$_{\textrm{HERA2}}$ PDFs agree well within the PDF errors, we continue to recommend CT14 PDFs for the analysis of LHC Run 2 experiments.