Scaling properties of spectra in new exact solutions of rotating, multi-component fireball hydrodynamics

TL;DR

This paper models the expansion of fireballs from quark matter to hadrons using a non-relativistic approach, revealing a secondary explosion near the QCD critical point and analyzing the temperature spectra of different hadrons.

Contribution

It introduces a new exact solution for rotating, multi-component fireball hydrodynamics with a non-relativistic approximation, highlighting a potential secondary explosion at the QCD critical point.

Findings

Identification of a secondary explosion at the QCD critical point

Effective temperature of hadrons depends linearly on their mass

Temperature spectra are influenced by radial flow and vorticity

Abstract

We describe fireballs that rehadronize from a perfect fluid of quark matter, characterized by the lattice QCD equation of state, to a chemically frozen, multi-component mixture, that contains various kinds of observable hadrons. For simplicity and clarity, we apply a non-relativistic approximation to describe the kinematics of this expansion. Unexpectedly, we identify a secondary explosion that may characterize fireball hydrodynamics at the QCD critical point. After rehadronization, the multi-component mixture of hadrons keeps on rotating and expanding together, similarly to a single component fluid. After kinetic freeze-out, the effective temperature $T_{i}$ of the single-particle spectra of hadron type $h_i$ is found to be a sum of the kinetic freeze-out temperature $T_f$ (that is independent of the hadron type $h_i$) and a term proportional to the mass $m_i$ of hadron type $h_i$. The coefficient of proportionality to $m_i$ is also found to be independent of the hadron type $h_i$ but be dependent on the radial flow and vorticity of collective dynamics.