Identify the best medium-response implementation for Z–hadron correlations in PbPb collisions

Determine which medium-response implementation—specifically the hydrodynamic positive and negative wake in the Hybrid strong/weak-coupling jet quenching model and the medium recoils with corresponding hole contributions in the JEWEL perturbative jet quenching model—provides the best description of the measured normalized associated yield distributions of charged hadrons relative to Z bosons in PbPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV, across azimuthal-angle (Δφ) and rapidity (Δy) differences and in charged-hadron transverse-momentum bins 1–2, 2–4, and 4–10 GeV.

Background

The paper presents the first measurement of Z boson–hadron two-particle correlations in PbPb collisions, analyzing normalized associated yields as functions of azimuthal-angle and rapidity differences in several charged-hadron pT bins and centrality classes. The results reveal a dip near the Z direction and an excess on the jet side, consistent with medium response effects such as hydrodynamic wakes and medium recoils.

Comparisons with several jet-quenching models (Hybrid, JEWEL, Pyquen, and Co-LBT) indicate that implementations including medium response provide better qualitative agreement with the data than those without. However, due to current statistical precision, the authors explicitly state that it is not clear which specific medium-response implementation best describes the measured distributions.