Extracting temperature and transverse flow by fitting transverse mass spectra and HBT radii together

Abstract

Single particle transverse mass spectra and HBT radii of identical pion and identical kaon are analyzed with a blast-wave parametrization under the assumptions local thermal equilibrium and transverse expansion. Under the assumptions, temperature parameter $T$ and transverse expansion rapidity $\rho$ are sensitive to the shapes of transverse mass $m_\text T$ spectrum and HBT radius $R_\text{s}(K_\text T)$. Negative and positive correlations between $T$ and $\rho$ are observed by fitting $m_\text{T}$ spectrum and HBT radius $R_\text s (K_\text T)$, respectively. For a Monte Carlo simulation using the blast-wave function, $T$ and $\rho$ are extracted by fitting $m_T$ spectra and HBT radii together utilizing a combined optimization function $\chi^2$. With this method, $T$ and $\rho$ of the Monte Carlo sources can be extracted. Using this method for A Multi-Phase Transport model (AMPT) at RHIC energy, the differences of $T$ and $\rho$ between pion and kaon are observed obviously, and the tendencies of $T$ and $\rho$ vs collision energy $\sqrt{s_\text{NN}}$ are similar with the results extracted directly from the AMPT model.