Spectra and radial flow in relativistic heavy ion collisions with Tsallis statistics in a blast-wave description

By Zebo Tang, Yichun Xu, L. Ruan, G. Buren, Fuqiang Wang, Zhangbu Xu. 2008

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We have implemented the Tsallis statistics in a Blast-Wave model (TBW) and applied it to midrapidity transverse-momentum spectra of identified particles measured at BNL Relativistic Heavy Ion Collider (RHIC). This new TBW function fits the RHIC data very well for p{sub T}<3 GeV/c. We observed that the collective flow velocity starts from zero in p+p and peripheral Au+Au collisions and grows to 0.470{+-}0.009c in central Au+Au collisions. The resulting (q-1) parameter, which characterizes the degree of nonequilibrium in a system, indicates an evolution from a highly nonequilibrated system in p+p collisions toward an almost thermalized system in central Au+Au collisions. The temperature and collective velocity are well described by a quadratic dependence on (q-1). Two sets of parameters in our TBW are required to describe the meson and baryon groups separately in p+p collisions while one set appears to fit all spectra in central Au+Au collisions.

Subfields: Nuclear and High Energy Physics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/5fc176f45039deeb5f702c3545fc5743692cc9a3