# Effects of jet-induced medium excitation in $\gamma$-hadron correlation in A+A collisions

## TL;DR

This paper introduces a coupled transport-hydrodynamics model to simulate jet-medium interactions in heavy-ion collisions, successfully reproducing experimental data and predicting soft hadron enhancements and azimuthal broadening.

## Contribution

The development of CoLBT-hydro, a GPU-accelerated (3+1)D simulation framework that models jet transport and medium excitation simultaneously in high-energy collisions.

## Key findings

- Accurately reproduces RHIC data on hadron suppression.
- Predicts soft hadron enhancement from jet-induced medium excitation.
- Shows broadening of soft hadron azimuthal distribution relative to jets.

## Abstract

Coupled Linear Boltzmann Transport and hydrodynamics (CoLBT-hydro) is developed for co-current and event-by-event simulations of jet transport and jet-induced medium excitation (j.i.m.e.) in high-energy heavy-ion collisions. This is made possible by a GPU parallelized (3+1)D hydrodynamics that has a source term from the energy-momentum deposition by propagating jet shower partons and provides real time update of the bulk medium evolution for subsequent jet transport. Hadron spectra in $\gamma$-jet events of A+A collisions at RHIC and LHC are calculated for the first time that include hadrons from both the modified jet and j.i.m.e.. CoLBT-hydro describes well experimental data at RHIC on the suppression of leading hadrons due to parton energy loss. It also predicts the enhancement of soft hadrons from j.i.m.e. The onset of soft hadron enhancement occurs at a constant transverse momentum due to the thermal nature of soft hadrons from j.i.m.e. which also have a significantly broadened azimuthal distribution relative to the jet direction. Soft hadrons in the $\gamma$ direction are, on the other hand, depleted due to a diffusion wake behind the jet.