Global Bayesian Analysis of $\mathrm{J}\mathrm{/}\psi$ Photoproduction on Proton and Lead Targets

We perform a global Bayesian analysis of diffractive $\mathrm{J}\mathrm{/}\psi$ production in $\gamma +p$ and $\gamma +\mathrm{P}\mathrm{b}$ collisions using a color glass condensate (CGC) based calculation framework. As past calculations have shown that CGC-based models typically overpredict the $\mathrm{J}\mathrm{/}\psi$ production in $\gamma +\mathrm{P}\mathrm{b}$ collisions at high center of mass energy, we address the question of whether it is possible to describe coherent and incoherent diffractive $\mathrm{J}\mathrm{/}\psi$ data from $\gamma +p$ collisions at HERA and the LHC, and from $\gamma +\mathrm{P}\mathrm{b}$ collisions at the LHC simultaneously. Our results indicate that a simultaneous description of $\gamma +p$ and $\gamma +\mathrm{P}\mathrm{b}$ data is challenging, with results improving when an overall $K$-factor – scaling $\gamma +p$ and $\gamma +\mathrm{P}\mathrm{b}$ cross sections to absorb model uncertainties – is introduced.