The nuclear shadowing effect of gluon at small x

The ratio of nuclear gluon distribution functions $x{g}^A/Axg$ in the saturation region at small x (i.e., $x\lesssim {10}^{-3}$) for light and heavy nuclei is investigated and compared with the HIJING2.0 model. The moments of the nuclear gluon distribution per nucleon, $<x^A{>}_g/A$, on a wide range of the scale μ with charm contribution are considered and compared with the parametrization groups. The importance of the binding energy for nuclei is also considered.