Heavy Quark Transport In Quark-gluon Plasma

In recent years,relativistic heavy-ion collisions performed at the Relativistic Heavy-Ion Collider(RHIC)at Brookhaven National Laboratory and the Large Hadron Collider(LHC)at CERN have discovered a new state of matter,which is referred to as the quark-gluon plasma(QGP).Two key experimental evidences that lead to the discovery of the QGP are strong collective flow of bulk matter,and jet quenching.The collective flow phenomenon refers to the fact that the bulk medium of the QGP undergoes a strong collective expansion after its initial creation.This behavior can be explained in great detail by relativistic viscous hydrodynamics.Jet quenching refers to the suppression of single inclusive hadron spectra at large transverse momen-tum.It is caused by the energy loss of jet partons produced from early hard scattering via elastic(collisional)and inelastic(radiative)interactions with the color-deconfined QGP medium before fragmenting into hadrons.There are many phenomenological studies of jet quenching such as the nuclear modifications of single inclusive hadron production,di-hadron and photon-hadron correlations,full jet observables.One of the major goals of these studies is to quantitatively extract jet transport coefficients in the QGP from systematic comparison with experimental data.Heavy quarks are important tools for studying the properties of QGP.Heavy quarks are produced from initial hard collisions.Due to their large mass compared to the temperature of the system,it is difficult for them to themalize.In the high transverse momentum region,heavy quarks lose energy primarily through inelastic scattering,while at the low transverse momentum interval,both elastic and inelastic scattering are important,for heavy quark energy loss.There exist many transport models for studying the production of heavy quarks and their evolution in QGP medium in relativistic heavy-ion collisions,such as par-ton cascade model based on Boltzmann equation,linearized Boltzmann transport or Langevin model coupled with hydrodynamics,and parton-hadron-string dynamics model.In this paper,we employ a quasi-particle model to describe the equation of state of QGP.Using the linearized Boltzmann transport model,together with the fluid dynamics model,we study the evolution of heavy quarks in the medium for RHIC LHC heavy ion collisions.For elastic scattering processes,we calculate the scattering rate using the perturbative QCD method,while the inelastic scattering process is described by the high twist energy loss model.Our model calculations for nuclear correction factor and elliptic flow of D meson are in good agreement with experimental data at RHIC and the LHC.