Dynamical model of antishadowing of the nuclear gluon distribution

Abstract

We explore the theoretical observation that within the leading twist approximation, the nuclear effects of shadowing and antishadowing in non-perturbative nuclear parton distribution functions (nPDFs) at the input QCD evolution scale involve diffraction on nucleons of a nuclear target and originate from merging of two parton ladders belonging to two different nucleons, which are close in the rapidity space. It allows us to propose that for a given momentum fraction $x_P$ carried by the diffractive exchange, nuclear shadowing and antishadowing should compensate each other in the momentum sum rule for nPDFs locally on the interval $\ln (x/x_P)\le 1$. We realize this by constructing an explicit model of nuclear gluon antishadowing, which has a wide support in $x$, $10^{-4}<x<0.2$, peaks at $x=0.05-0.1$ at the level of $\approx 15$\% for ${}^{208}$Pb at $Q_0^2=4$ GeV${}^2$ and rather insignificantly depends on details of the model. We also studied the impact parameter $b$ dependence of antishadowing and found it to be slow.

11 pages, 9 figures. Additional figures and discussion to compare to competing approaches. Final published version

References in corpus (4)

• EPS09 - a New Generation of NLO and LO Nuclear Parton Distribution Functions
• EPPS16: Nuclear parton distributions with LHC data
• Determination of nuclear parton distribution functions and their uncertainties at next-to-leading order
• Centrality Dependence of pi^0 and eta Production at Large Transverse Momentum in sqrt(s_NN) = 200 GeV d+Au Collisions

Cited by in corpus (12)

• Gluon Shadowing in Heavy-Flavor Production at the LHC
• First determination of $D^{\ast +}$-meson fragmentation functions and their uncertainties at next-to-next-to-leading order
• Selected topics in diffraction with protons and nuclei: past, present, and future
• Study of spin-dependent structure functions of ${}^3\mathrm{He}$ and ${}^3\mathrm{H}$ at NNLO approximation and corresponding nuclear corrections
• Nuclear parton density functions from dijet photoproduction at the EIC
• Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab
• Application of the rescaling model at small Bjorken $x$ values
• The gluon and charm content of the deuteron
• Probing impact-parameter dependent nuclear parton densities from double parton scatterings in heavy-ion collisions
• Gluon Shadowing and Nuclear Entanglement
• EMC effect at small Bjorken x values
• Parton distribution functions with QED corrections in the valon model