System-size dependence of $\gamma$-jet modifications in heavy-ion collisions

Abstract

Medium modifications of the $\gamma$-triggered jets are investigated with the Linear Boltzmann Transport (LBT) model in heavy-ion collisions with varying system sizes, focusing on centrality dependence in Pb+Pb and Xe+Xe collisions at the LHC. Our numerical results reveal that jets produced in central collisions exhibit a wider transverse asymmetry ($A_N^y$) distribution, a broader jet shape, and a more pronounced $\gamma$-jet transverse momentum imbalance ($X_{J\gamma}=p_T^{\rm jet}/p_T^\gamma$) compared to peripheral collisions. These effects arise from the longer path length and stronger jet-medium interactions in central collisions, leading to enhanced jet quenching and medium response. Our findings demonstrate that the magnitude of $\gamma$-jet modifications is sensitive to the size and centrality of the collision system, with larger systems inducing more significant alterations due to increased energy loss and medium feedback.