Probing subnucleon scale fluctuations in ultraperipheral heavy ion collisions

We show that introducing subnucleon scale fluctuations constrained by HERA diffractive $J/\Psi$ production data significantly affects the incoherent diffractive $J/\Psi$ production cross section in ultraperipheral heavy ion collisions. We find that the inclusion of the additional fluctuations increases the ratio of the incoherent to the coherent cross section approximately by a factor of $2$, and modifies the transverse momentum spectra of the produced $J/\Psi$ at momenta larger than the scale that corresponds to the distance scale of the subnucleonic fluctuations. We present predictions for $J/\Psi$ production in ultraperipheral heavy ion collisions at $\sqrt{s_{NN}}=5.02\,{\rm TeV}$ at the LHC and $200\,{\rm GeV}$ at RHIC.