Nuclear parton distributions at next to leading order

TL;DR

This work addresses the determination of nuclear parton distribution functions by performing a global QCD analysis of nuclear DIS and Drell–Yan data using a convolution parameterization. It introduces the first full next-to-leading order (NLO) extraction of nPDFs and uses Mellin-space evolution for numerical efficiency. The results show improved data agreement over previous LO extractions and reveal significant differences in the Q^2 evolution of nuclear effects, particularly for sea quarks and gluons. The study provides practical nPDF sets and underscores the necessity of NLO nPDFs for reliable predictions in nuclear processes such as heavy-ion collisions and neutrino-nucleus interactions.

Abstract

We perform a next to leading order QCD global analysis of nuclear deep inelastic scattering and Drell-Yan data using the convolution approach to parameterize nuclear parton densities. We find both a significant improvement in the agreement with data compared to previous extractions, and substantial differences in the scale dependence of nuclear effects compared to leading order analyses.

Figures (10)

• Figure 1: $F_2^A/F_2^D$ data. The lines interpolate the values obtained with the NLO nPDF set at the respective $Q^2$, and extrapolate to low $x_N$ at the $Q^2$ leftmost point.
• Figure 2: The same as Fig. 1 but for $F_2^A/F_2^C$ data
• Figure 3: Data on nuclear Drell Yan cross sections rates to deuterium and those computed with NLO nPDF.
• Figure 4: Scale dependence of $F_2^{Sn}/F_2^{C}$ data and the outcome of NLO nPDF.
• Figure 5: A-dependence of the parameters.