# Temperature and fluid velocity on the freeze-out surface from $\pi$, $K$, $p$ spectra in pp, p--Pb and Pb--Pb collisions

## TL;DR

This paper introduces a rapid method to incorporate resonance decays into blast-wave model fits of hadron spectra, enabling quick extraction of freeze-out parameters across different collision systems and multiplicities.

## Contribution

The authors develop a new approach with pre-calculated decay spectra that improves blast-wave fits by accurately accounting for resonance feed-down effects.

## Key findings

- Freeze-out temperature around 150 MeV with weak multiplicity dependence
- Method allows rapid extraction of freeze-out parameters
- Discussion of chemical vs kinetic freeze-out separation

## Abstract

We present a new approach to take into account resonance decays in the blast-wave model fits of identified hadron spectra. Thanks to pre-calculated decayed particle spectra, we are able to extract, in a matter of seconds, the multiplicity dependence of the single freeze-out temperature $T_{\rm fo}$, average fluid velocity $\left<\beta_{\rm T}\right>$, velocity exponent $n$, and the volume $dV/dy$ of an expanding fireball. In contrast to blast-wave fits without resonance feed-down, our approach results in a freeze-out temperature of $T_{\rm fo}\approx 150\,\text{MeV}$, which has only weak dependence on multiplicity and collision system. Finally, we discuss separate chemical and kinetic freeze-outs separated by partial chemical equilibrium.