Orateur
Guillermo Contreras
(Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic)
Description
ALICE has measured the diffractive photo-nuclear cross section for coherent J$/\psi$ production off lead (Pb) nuclei. This process is highly sensitive to the gluon distribution in Pb. This measurement reaches centre-of-mass energies of the photon-nucleus system up to 813 GeV which is more than 340 GeV larger than ever before. It also covers three orders of magnitude of the relevant variable, Bjorken-$x$, with cross sections measured from $x\sim 10^{-2}$ to $x\sim 10^{-5}$.
This unprecedented coverage allows for probing the gluonic structure of the Pb nuclei at the lowest Bjorken-$x$ possible with any current experiment, challenging both gluon saturation and shadowing models to describe the data.
Auteur principal
Guillermo Contreras
(Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic)
