The Impact of LHC Jet Data on the MMHT PDF Fit at NNLO

TL;DR

This paper assesses how high-precision LHC jet data influences the MMHT global parton distribution functions at NNLO, highlighting the importance of systematic error treatment and the effects of NNLO corrections on gluon distribution uncertainties.

Contribution

It introduces a simplified method for incorporating ATLAS and CMS jet data into NNLO PDF fits and analyzes the impact on the gluon PDF with different scale choices and jet radii.

Findings

Good data description requires improved systematic error treatment.

NNLO corrections slightly improve fit quality and impact on gluon PDFs.

Impact on gluon distribution is relatively insensitive to scale and jet radius choices.

Abstract

We investigate the impact of the high precision ATLAS and CMS 7 TeV measurements of inclusive jet production on the MMHT global PDF analysis at next-to-next-to-leading order (NNLO). This is made possible by the recent completion of the long-term project to calculate the NNLO corrections to the hard cross section. We find that a good description of the ATLAS data is not possible with the default treatment of experimental systematic errors, and develop a simplified solution that retains the dominant physical information of the data. We then investigate the fit quality and the impact on the gluon PDF central value and uncertainty when the ATLAS and CMS data are included in a MMHT fit. We consider both common choices for the factorization and renormalization scale, namely the inclusive jet transverse momentum, $p_\perp$, and the leading jet $p_\perp$, as well as the different jet radii for which the ATLAS and CMS data are made available. We find that the impact of these data on the gluon is relatively insensitive to these inputs, in particular the scale choice, while the inclusion of NNLO corrections tends to improve the data description somewhat, and gives a qualitatively similar though not identical impact on the gluon in comparison to NLO.