English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The equation of state $p(\epsilon)$ and speed of sound squared $c_s^2$ arestudied in grand canonical ensemble of all hadron resonances having masses$\leq 2\,$GeV. This large ensemble is divided into strange and non-strangehadron resonances and furthermore to pionic, bosonic and femionic sectors. Itis found that the pions represent the main contributors to $c_s^2$ and otherthermodynamic quantities including the equation of state $p(\epsilon)$ at lowtemperatures. At high temperatures, the main contributions are added in by themassive hadron resonances. The speed of sound squared can be calculated fromthe derivative of pressure with respect to the energy density, $\partialp/\partial \epsilon$, or from the entropy-specific heat ratio, $s/c_v$. It isconcluded that the physics of these two expressions is not necessarilyidentical. They are distinguishable below and above the critical temperature$T_c$. This behavior is observed at vanishing and finite chemical potential. Athigh temperatures, both expressions get very close to each other and both ofthem approach the asymptotic value, $1/3$. In the HRG results, which are onlyvalid below $T_c$, the difference decreases with increasing the temperature andalmost vanishes near $T_c$. It is concluded that the HRG model can very wellreproduce the results of the lattice quantum chromodynamics (QCD) of $\partialp/\partial \epsilon$ and $s/c_v$, especially at finite chemical potential. Inlight of this, energy fluctuations and other collective phenomena associatedwith the specific heat might be present in the HRG model. At fixedtemperatures, it is found that $c_s^2$ is not sensitive to the chemicalpotential.

Hadronic Equation of State and Speed of Sound in Thermal and Dense Medium