A QCD analysis of CMS inclusive differential Z production data at sqrt(s) = 8 TeV

TL;DR

This paper analyzes CMS Z boson production data at 8 TeV to improve understanding of proton PDFs, especially the gluon distribution, using NLO theory and HERAFitter, showing moderate improvements.

Contribution

It provides a detailed comparison of CMS Z production data with NLO predictions and assesses the data's impact on gluon PDFs within the HERAFitter framework.

Findings

Moderate improvement to gluon PDF at x ~ 0.1

Data constrains PDFs within current theoretical framework

Higher-order calculations are needed for further improvements.

Abstract

The parton distribution functions (PDFs) of the proton are one of the essential ingredients to describe physics processes at hadron colliders. The Z boson production data at the LHC have a potential to constrain PDFs, especially the gluon distribution. In this study the CMS measurement of the inclusive double differential Z boson production cross section in terms of transverse momentum and rapidity are compared to the next-to-leading order theory predictions at the center-of-mass energy of sqrt(s)=8 TeV with an integrated luminosity of 19.71 inverse femtobarns. In addition, the sensitivity of this measurement to PDFs is studied within the framework of the HERAFitter. A moderate improvement to the gluon distribution is observed at the Bjorken x ~ 0.1 region. However, in order to obtain further improvement to the gluon distribution in the global fits, the higher-order theory calculations accessible via fast techniques are necessary.