Speaker
Prof.
Che-Ming Ko
(Texas A&M University)
Description
Using a two-component model for J/Ψ production, which includes both from initial hard nucleon-nucleon scattering and from regeneration in the produced quark-gluon plasma, we have studied the nuclear modification factor RAA and elliptic flow v2 of J/Ψ in Au+Au collision at sNN1/2=200 GeV. For the expansion dynamics of produced hot dense matter, we have introduced a schematic fireball model with its transverse acceleration determined from the pressure gradient inside the fireball and azimuthally anisotropic expansion parameterized to reproduce measured v2 of light hadrons. We assume that light hadrons freeze out at the temperature of 120 MeV while J/Ψ at 160 MeV, similar to, respectively, the kinetic and chemical freeze-out temperatures in the statistical model. For the properties of J/Ψ in the quark-gluon plasma, we use the perturbative QCD (pQCD) to calculate the screening mass between their charm quarks in the leading order and their dissociation cross sections up to the next-to-leading order. For the relaxation time of charm quarks in the quark-gluon plasma, it is also calculated in the leading order of pQCD. Modeling the effect of higher-order corrections in pQCD by introducing multiplicative constants to the dissociation cross section of J/Ψ and the elastic cross section of charm quarks, we find that their effects are small on the RAA of J/Ψ as they suppress the number of initially produced J/Ψ but enhance the number of regenerated ones. The higher-order corrections increase, however, the v2 of J/Ψ. Our results suggest that studying the v2 of J/Ψ provides the possibility to discriminate between the two J/Ψ production mechanisms from initial hard scatterings and from regeneration in the quark-gluon plasma.
Primary author
Prof.
Che-Ming Ko
(Texas A&M University)
Co-author
Dr
Taesoo Song
(Texas A&M University)
