Inelastic J ψ production in deep inelastic scattering from hydrogen and deuterium and the gluon distribution of free nucleons

Abstract

We present results on inelastic J/ψ production from muon interactions with hydrogen and deuterium at an incident muon energy of 280 GeV. The measured cross section ratio per nucleon for muon-induced J ψ production in deuterium and hydrogen was found to be R(D2/H2) = 1.01±0.15. The colour singlet model is shown to provide a good description of the observed differential cross section apart from a normalisation factor. The comparison between the observed cross section and the colour singlet model prediction allows the extraction of the gluon structure function G(x) of the nucleon. The momentum fraction x of the nucleon carried by the gluon is measured in the range of x = [0.02, 0.30]. The norma..