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

TL;DR

This paper introduces a combined fitting method for transverse mass spectra and HBT radii to extract temperature and transverse flow parameters in heavy-ion collisions, validated with simulations and applied to AMPT model data.

Contribution

It presents a novel combined fitting approach to simultaneously determine temperature and transverse flow from spectra and HBT radii, improving analysis accuracy.

Findings

Successfully extracted T and ρ from Monte Carlo simulations.

Observed differences in T and ρ between pions and kaons in AMPT model.

T and ρ trends with collision energy are consistent with direct AMPT results.

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.