Evidence for J/ψ Suppression in Incoherent Photonuclear Production

Le résumé fourni par la source

According to quantum chromodynamics, at sufficiently high energy, the structure of hadrons reveals a dynamic equilibrium between gluon splitting and gluon recombination - a phenomenon known as saturation. The process of diffractive photonuclear production of a J/ψ vector meson provides a direct insight into the gluon composition of hadrons. The J/ψ production as a function of momentum transferred in the interaction, quantified by the Mandelstam-t variable, serves as an excellent probe for studying the structure of hadrons within the impact-parameter plane, because different ranges in t are sensitive to the dynamics of the gluon field at varying spatial size scales. The ALICE Collaboration has measured the energy dependence of incoherent photonuclear production of J/ψ mesons off lead ions, at sNN=5.02 TeV, for three Mandelstam-t intervals. The energy dependence of the photonuclear cross section at the highest |t| range measured, (0.81<|t|<1.44) GeV2, is sensitive to subnucleonic structures of the Pb target. The increase of the cross section with energy at large |t| shows evidence of suppression with respect to the increase seen at low |t|. The observed pattern of the energy evolution in data is similar to that of gluon saturation models.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.