Momentum imbalance of isolated photon-tagged jet production at RHIC and LHC

TL;DR

This paper compares photon-tagged jet production in heavy-ion collisions at RHIC and LHC, analyzing how the medium modifies jet momentum imbalance due to parton energy loss, providing theoretical predictions for experimental interpretation.

Contribution

It presents the first calculations of photon-tagged jet cross sections at RHIC and LHC energies, highlighting the energy-dependent effects of the medium on jet imbalance.

Findings

Increased transverse momentum imbalance due to medium interactions.

Quantitative predictions for jet quenching effects at different energies.

Framework for interpreting photon-jet measurements in heavy-ion collisions.

Abstract

In collisions of ultra-relativistic nuclei, photon-tagged jets provide a unique opportunity to compare jet production and modification due to parton shower formation and propagation in strongly-interacting matter at vastly different center-of-mass energies. We present first results for the cross sections of jets tagged by an isolated photon to ${\cal O}(\alpha_{\rm em} \alpha_s^2)$ in central Au+Au reactions with $\sqrt{s_{NN}}=200$ GeV at RHIC and central Pb+Pb reactions with $\sqrt{s_{NN}}=2.76$ TeV at LHC. We evaluate the increase in the transverse momentum imbalance of the observed $\gamma$+jet state, induced by the dissipation of the parton shower energy due to strong final-state interactions. Theoretical predictions to help interpret recent and upcoming experimental data are presented.