The Z^0-tagged jet event asymmetry in heavy-ion collisions at the CERN Large Hadron Collider

TL;DR

This paper presents the first calculation of the transverse momentum asymmetry in Z^0-tagged jet events in heavy-ion collisions at the LHC, combining perturbative and medium-induced effects.

Contribution

It introduces a novel theoretical calculation of jet asymmetry in heavy-ion collisions, incorporating both perturbative QCD and medium modifications.

Findings

Strong asymmetry observed in central lead-lead collisions

Asymmetry shows little sensitivity to soft background fluctuations

Model predictions for asymmetry shape and magnitude provided

Abstract

Tagged jet measurements provide a promising experimental channel to quantify the similarities and differences in the mechanisms of jet production in proton-proton and nucleus-nucleus collisions. We present the first calculation of the transverse momentum asymmetry of Z^0/gamma^*-tagged jet events in sqrt{s}=2.76$ TeV reactions at the LHC. Our results combine the O(G_F\alpha_s^2) perturbative cross sections with the radiative and collisional processes that modify parton showers in the presence of dense QCD matter. We find that a strong asymmetry is generated in central lead-lead reactions that has little sensitivity to the fluctuations of the underlying soft hadronic background. We present theoretical model predictions for its shape and magnitude.