The particle spectra and Hanbury-Brown Twiss (HBT) radius of Au+Au collisions at RHIC energy are investigated by a hydrodynamical expanding source with both shear and bulk viscosities (ζ).With a large width of the ratio of ζ to entropy density s,both the particle transverse momentum spectra and the ratio Rout/Rside of HBT radii in the direction of the total transverse momentum of detected two particles (Rout) and perpendicular to both this direction and the beam direction (Rside) become a little steeper.
With a multi-phase transport (AMPT) model,a γ-jet with known production point and momentum is triggered to search for the origin of double-peak structure in di-hadron azimuthal correlation in central Au+Au collisions at RHIC energy.The different configurations of triggered γ-jet produce different shapes of medium responses.The key of the double-peak structure is found to be a strong shadowing effect of dense core,which is related to transverse expansion and radial flow of partonic matter.
Production and properties of φ-meson under the extreme hot dense matter which is formed in Au + Au collisions at RHIC energy have been briefly reviewed.The issues are focused on transverse momentum (p T ) spectra of φ,elliptic flow of φ,nuclear modification factor of φ,the ratio of Ω(p T )/φ(p T ) versus p T,the ratio of Ω(p T /3)/φ(p T /2) versus p T /n q,spin alignment of φ and the enhancement of φ etc.These observables give the significant information of the strange quark dynamics in hot dense matter under the extreme condition.
