Strangeness thermodynamic instabilities in hot and dense nuclear matter

TL;DR

This paper investigates thermodynamic instabilities and potential phase transitions in hot, dense nuclear matter using a relativistic mean-field model that includes hyperons, $\Delta$-isobars, and mesons, revealing conditions for a hadronic phase transition.

Contribution

It demonstrates the possibility of a hadronic phase transition with strangeness fluctuations in nuclear matter, extending understanding of phase behavior at finite baryon density.

Findings

Phase transition characterized by mechanical and chemical instabilities.

Strangeness content varies during the mixed phase.

Conditions for phase transition depend on $\Delta$-meson coupling constants.

Abstract

We explore the presence of thermodynamic instabilities and, con\-se\-quen\-tly, the realization of a pure hadronic phase transition in the hot and finite baryon density nuclear matter. The analysis is performed by means of an effective relativistic mean-field model with the inclusion of hyperons, $\Delta$-isobars, and the lightest pseudoscalar and vector meson degrees of freedom. The Gibbs conditions on the global conservation of baryon number and zero net strangeness in symmetric nuclear matter are required. Similarly to the liquid-gas phase transition, we show that a phase transition, characterized by mechanical instabilities (due to fluctuations on the baryon number) and chemical-diffusive instabilities (due to fluctuations on the strangeness number), can take place for a finite range of $\Delta$-meson coupling constants, compatible with different experimental constraints. The hadronic phase transition, which presents similar features to the quark-hadron phase transition, is characterized by different strangeness content during the mixed phase and, consequently, by a sensible variation of the strange anti-particle to particle ratios.