Two-pion Interferometer For Viscous Hydrodynamic Sources

One of the most significant motivations of relativistic heavy ion collision is to product a new state of matter called quark-gluon plasma (QGP) and research its new characteristics and new phenomenon, which is defined as a thermalzed state of quarks and gluons without color confinement. Since the QGP produced in the early stage of collisions and the finally observed information only hadronic matter, the center of relativistic heavy-ion collisions include the formation conditions of QGP, the evolution of QGP and the final observed information. The experiments have showed that the behave of QGP like a perfect liquid, so we can use fluid dynamics to describe its evolution.First, we briefly review the basis of a viscous fluid dynamics and introduce the basic equations of ideal fluid and viscous fluid. Second, we used space-time evolution source of the (1+1)-dimensional viscous hydrodynamics to discuss the influence of the shear and bulk viscosities on the evolution of system and the two-pion Hanbury-Brown-Twiss (HBT) interferometry. We find that the evolution of system become slowly if take into account viscosities. The HBT analyses indicate the effect on the two-pion HBT result is small if we only consider shear viscosity. But transverse HBT radio are increased when we taken into bulk viscosity. Moreover, when we consider the viscous coefficient change with temperature, we find a larger HBT radius in side direction, but its effect on the longitudinal HBT radius is small.