nCTEQ15 - Global analysis of nuclear parton distributions with uncertainties in the CTEQ framework

TL;DR

The paper introduces the nCTEQ15 nuclear parton distribution functions with uncertainties, extending proton PDFs to nuclei up to lead, using diverse data and advanced uncertainty quantification methods.

Contribution

This work provides the first comprehensive nPDF set with uncertainties using the Hessian method, incorporating multiple data types and comparing with other recent fits.

Findings

nCTEQ15 includes uncertainties for nuclear PDFs.

Inclusion of RHIC pion data constrains nuclear gluon distributions.

Comparison shows consistency with other nPDF fits.

Abstract

We present the new nCTEQ15 set of nuclear parton distribution functions with uncertainties. This fit extends the CTEQ proton PDFs to include the nuclear dependence using data on nuclei all the way up to 208^Pb. The uncertainties are determined using the Hessian method with an optimal rescaling of the eigenvectors to accurately represent the uncertainties for the chosen tolerance criteria. In addition to the Deep Inelastic Scattering (DIS) and Drell-Yan (DY) processes, we also include inclusive pion production data from RHIC to help constrain the nuclear gluon PDF. Furthermore, we investigate the correlation of the data sets with specific nPDF flavor components, and asses the impact of individual experiments. We also provide comparisons of the nCTEQ15 set with recent fits from other groups.