Reweighted nuclear PDFs using Heavy-Flavor Production Data at the LHC: nCTEQ15_rwHF & EPPS16_rwHF

TL;DR

This paper reweights existing nuclear parton distribution functions using new heavy-flavor production data from the LHC, reducing uncertainties and validating the universality of the small-x gluon distribution within the collinear factorization framework.

Contribution

It introduces reweighted nuclear PDFs, nCTEQ15_rwHF and EPPS16_rwHF, incorporating heavy-flavor data to improve accuracy and validate the universality of gluon distributions.

Findings

Reweighted PDFs have significantly smaller uncertainties.

Heavy-flavor data are well described by the reweighted PDFs.

Validation confirms the universality of the small-x gluon distribution.

Abstract

We present the reweighting of two sets of nuclear PDFs, nCTEQ15 and EPPS16, using a selection of experimental data on heavy-flavor meson [D0, J/psi, J/psi from B and Upsilon(1S)] production in proton-lead collisions at the LHC which were not used in the original determination of these nuclear PDFs. The reweighted PDFs exhibit significantly smaller uncertainties thanks to these new heavy-flavor constraints. We present a comparison with another selection of data from the LHC and RHIC which were not included in our reweighting procedure. The comparison is overall very good and serves as a validation of these reweighted nuclear PDF sets, which we dub nCTEQ15_rwHF & EPPS16_rwHF. This indicates that the LHC and forward RHIC heavy-flavor data can be described within the standard collinear factorization framework with the same (universal) small-x gluon distribution. We discuss how we believe such reweighted PDFs should be used as well as the limitations of our procedure.