Hadron productions and jet substructures associated with $Z^0/\gamma$ in Pb+Pb collisions at the LHC

Abstract

We carry out a detailed study of medium modifications on $Z^0$/$\gamma$+hadron correlations as well as jet substructures in association with $Z^0/\gamma$ in Pb+Pb collisions with $\sqrt{s_{NN}}=5.02$ TeV at the LHC. We utilize the Linear Boltzmann transport (LBT) model to simulate the jet-medium interactions and medium response, and an extended cluster hadronization model to investigate the non-perturbative transition of quarks and gluons into final hadrons in heavy-ion collisions. Including hadronization effect, we can well describe $Z^0/\gamma$+hadrons correlations and $Z^0/\gamma$-tagged jet substructures in both p+p and Pb+Pb collisions simultaneously. Medium modification on jet profile and jet fragmentation functions indicate that particles carrying a large fraction of the jet momentum are generally closely aligned with the jet axis, whereas low-momentum particles are observed to have a much broader angular distribution relative to jet axis in Pb+Pb collisions due to jet-medium interactions. In particular, we find that $Z^0/\gamma$-tagged hadron correlations are sensitive to the soft particles from the dense medium and medium response, while jet-substructures show weak dependence on those soft hadrons with only a fraction of them falling inside the jet area