EPS09 - Nuclear PDFs and Their Uncertainties at NLO

TL;DR

This paper introduces EPS09, a set of nuclear parton distribution functions at NLO, incorporating diverse experimental data and providing the first Hessian error analysis for nPDF uncertainties.

Contribution

It presents the first Hessian error analysis for nPDFs and extends previous NLO analyses by including RHIC pion data to better constrain gluon densities.

Findings

Reduced uncertainties in nuclear gluon densities.

First Hessian error sets for nPDFs.

Improved fit to experimental data.

Abstract

In this talk, we present our recent next-to-leading order (NLO) nuclear parton distribution functions (nPDFs), which we call EPS09. As an extension to earlier NLO analyses, we supplement the deep inelastic scattering and Drell-Yan dilepton data by inclusive midrapidity pion measurements from RHIC in order to reduce the otherwize large freedom in the nuclear gluon densities. Our Hessian-type error analysis leading to a collection of nPDF error sets, is the first of its kind among the nPDF analyses.