Heikki Mäntysaari, Hendrik Roch, Farid Salazar, Björn Schenke, Chun Shen, Wenbin Zhao
We perform a global Bayesian analysis of diffractive J / ψ production in γ + p and γ + Pb collisions using a color glass condensate (CGC) based calculation framework. As past calculations have shown that CGC-based models typically overpredict the J / ψ production in γ + Pb collisions at high center of mass energy, we address the question of whether it is possible to describe coherent and incoherent diffractive J / ψ data from γ + p collisions at Hadron–Electron Ring Accelerator (HERA) and the LHC, and from γ + Pb collisions at the LHC simultaneously. Our results indicate that a simultaneous description of γ + p and γ + Pb data is challenging, with results improving when an overall K -factor—scaling γ + p and γ + Pb cross sections to absorb model uncertainties—is introduced.