Evaluating the ratio of the exclusive vector meson photoproduction to inclusive hadron/jet production cross section in ultraperipheral heavy ion collisions

Abstract

Using the QCD color dipole picture to study exclusive vector meson and inclusive jet/open meson photoproduction, we calculate the ratio of elastic meson production to inclusive hadron production cross sections for ultraperipheral heavy ion collisions. Predictions are evaluated for run 4 of the Large Hadron Collider in proton-nucleus ($pA$) and nucleus-nucleus ($AA$) collisions. The dependencies of the ratio on jet/hadron transverse momentum and atomic number are investigated. The double ratio $R_{\mathrm{UPC}}$ for $AA$ over $pA$ collisions is also computed, which has been previously proposed as a new observable probing parton saturation physics.