Heavy quark energy loss and angular de-correlation in a quark-gluon plasma matter

We study heavy quark energy loss in a hot and dense nuclear matter in the framework of Langevin equation coupled to a (2+1)-dimensional hydrodynamic model. The classical Langevin framework is modified such that both quasi-elastic scattering and gluon radiation are incorporated. We provide good description of D meson suppression measured by the ALICE collaboration. We further investigate the angular correlation function of c c-bar pairs, and find that it can be potentially employed to distinguish different energy loss mechanisms of heavy quarks inside QGP