Exclusive diffractive $J/\psi$ and $\psi \left(2S\right)$ production in dipole model using a holographic $\mathrm{AdS}/\mathrm{QCD}$ light-front wavefunction with longitudinal confinement

We use anti-de Sitter/quantum chromodynamics based holographic light-front wavefunction (LFWF) for vector meson, in conjunction with the dipole model to investigate the cross sections data for the diffractive and exclusive $J/\psi$ and $\psi \left(2S\right)$ production. We confront the experimental data using a new explicit form of the holographic LFWF, where the longitudinal confinement dynamics in the light-front Schrödinger equation is captured by the 't Hooft equation of ($1+1$)-dim, in large $N_c$ approximation, in addition to the transverse confinement dynamics governed by the confining mass scale parameter $\kappa$ in vector mesons. We obtain the LFWF parameters from fitting to the exclusive $J/\psi$ electroproduction data from the electron-proton collision at the Hadron Electron Ring Accelerator collider for $m_c=1.27\mathrm{GeV}$. Our results suggest that the dipole model together with holographic meson LFWFs with longitudinal confinement is able to give a successful description for differential scattering cross section for exclusive $J/\psi$ electroproduction for H1 and ZEUS data. We also predict the rapidity distributions of differential scattering cross section and total photoproduction of $J/\psi$ and $\psi \left(2S\right)$ states in proton-proton ultraperipheral collisions (UPCs) at center of mass energy $\sqrt{s}=7,13\mathrm{TeV}$. Using the minimum set of parameters, our predictions for the UPCs are in good agreement with the recent experimental observations of UPCs at ALICE and LHCb Collaborations.