Constraints for nuclear gluon shadowing from DIS data

AbstractThe Q2-dependence of the ratios of the cross sections of deep inelastic lepton–nucleus scattering is studied in the framework of leading twist, lowest order perturbative QCD. The logQ2 slope of the ratio F2Sn/F2C is computed by using the DGLAP evolution equations, and shown to be sensitive to the nuclear gluon distribution functions. Four different parametrizations for the nuclear effects of parton distributions are studied. We show that the NMC data on the Q2-dependence of F2Sn/F2C rule out the case where nuclear shadowing (suppression) of gluons at x∼0.01 is much larger than the shadowing observed in the ratio F2A/F2D. We also show that the possible non-linear correction terms due to gluon fusion in the evolution equations do not change this conclusion. Some consequences for computation of RHIC multiplicities, which probe the region x≳0.01, are also discussed