Constraints on nuclear gluon densities from J/psi data

Francois Arleo (1)

1 LAPTH - Laboratoire d'Annecy-le-Vieux de Physique Théorique

The gluon density in nuclei, G^A(x), is poorly constrained at all x from the current DIS and Drell-Yan data. In this paper, we point out that J/psi production measured in proton-nucleus collisions at sqrt(s)=38.8 GeV by the E866 collaboration puts stringent constraints on the x-dependence of the G^W/G^Be ratio in the x=0.02-0.1 range. The E866 data suggest a rather mild x-dependence of G^W/G^Be, and consequently tend to favour DS and HKM sets, rather than the DSg, EKS, and EPS parametrizations which exhibit a large shadowing and anti-shadowing.

Domaines: Physique des Hautes Energies - Phénoménologie [hep-ph]

Francois Arleo. Constraints on nuclear gluon densities from J/psi data. 2008. ⟨hal-00274202⟩