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

TL;DR

This paper uses the QCD color dipole model to predict the ratio of exclusive vector meson photoproduction to inclusive hadron/jet production in ultraperipheral heavy ion collisions at the LHC, exploring its dependence on various parameters.

Contribution

It provides new theoretical predictions for the ratio of exclusive to inclusive cross sections in ultraperipheral collisions, including the double ratio as a probe of parton saturation.

Findings

Predicted the ratio of exclusive vector meson to inclusive hadron/jet production at LHC energies.

Analyzed the dependence of the ratio on jet transverse momentum and atomic number.

Computed the double ratio $R_{UPC}$ as a novel observable for saturation physics.

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.