Temperature and fluid velocity on the freeze-out surface from π, K, p spectra in pp, p–Pb and Pb–Pb collisions

Abstract:

We present a new approach to take into account resonance decays in the blast-wave model fits of identified hadron spectra. Thanks to precalculated decayed particle spectra, we are able to extract, in a matter of seconds, the multiplicity dependence of the single freeze-out temperature $T_{\mathrm{fo}}$, average fluid velocity $⟨{\beta }_T⟩$, 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 $T_{\text{fo}}\approx 150\text{MeV}$, which has only weak dependence on multiplicity and collision system. Finally, we discuss separate chemical and kinetic freeze-outs separated by partial chemical equilibrium.

A. Mazeliauskas, V. Vislavicius, „Temperature and fluid velocity on the freeze-out surface
from π, K, p spectra in pp, p–Pb and Pb–Pb collisions“, Phys. Rev. C 101, 014910 (2020).

https://journals.aps.org/prc/abstract/10.1103/PhysRevC.101.014910

Related to Project A01, C06