Correlations Of D(?) Pairs In Relativistic Heavy-ion Collisions

High energy heavy ion collisions lead to the formation of a hot quark-gluon plasma.Heavy quarks that form in the early stages of collisions loss energy during their passage through the quark-gluon plasma(this phenomenon is known as jet quenching).They are important hard probes to study the properties of quark gluon plasma.In addition to single inclusive observables,correlations of final state particles play a very important role in the study of jet quenching and parton energy loss.We study the angular correlations and energy imbalance between heavy quark pairs and heavy meson pairs in ultra-relativistic heavy-ion collisions.There are many phenomenological models to describe the evolution of heavy quarks inside the thermalized medium.In our study,the evolution of charm quark pair in QGP medium is simulated by the linearized Boltzmann transport model.There are two energy loss mechanisms:elastic scattering and inelastic scattering.The scattering cross section,the scattering probability and the medium-incluced emission rate are calculated by perturbation QCD and higher twist energy loss model.The hadronization of heavy quarks is performed utilizing a hybrid model of fragmentation and coalescence.We study in detail the angular correlations and energy imbalance between back-to-back heavy quark pairs in the static medium and the dynamic medium produced in the collisions of Pb-Pb@2760GeV.We find that the momentum broadening and energy imbalance between the back-to-back heavy quark pairs have strong dependence on the evolution time and initial energy in the static medium,as well as the collision centrality in the collisions of Pb-Pb@2760GeV.It is interesting to find that a significant part of the energy imbalance of heavy quark pairs is caused by the energy loss fluctuations.