Towards detailed tomography of high energy heavy-ion collisions by $\gamma$-jet

Abstract

Within a multi-phase transport (AMPT) model with string melting scenario, the transverse momentum imbalance between prompt photon and jet is studied in Pb+Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 2.76 TeV. Jet loses more energy in more central collisions due to strong partonic interactions between jet parton shower and partonic matter, which is more significant than due to hadronic interactions only. The hadronization and final-state hadronic interactions have little influences on the imbalance. The imbalance ratio $x_{j\gamma}$ is sensitive to both production position and passing direction of $\gamma$-jet, which provides an opportunity to do detail $\gamma$-jet tomography on the formed partonic matter by selecting different $x_{j\gamma}$ ranges. It is also proposed that $\gamma$-hadron azimuthal correlation associated with photon+jet is a probe to see the medium responses to different $\gamma$-jet production configurations.