Compact Stars, Heavy Ion Collisions, and Possible Lessons For QCD at Finite Densities

TL;DR

This paper discusses how observations of neutron stars and heavy ion collisions provide complementary constraints on the equation of state of dense matter, helping to refine models of QCD at finite densities.

Contribution

It demonstrates how combining astrophysical and experimental data constrains effective models of dense matter's equation of state.

Findings

Neutron star mass measurements set a lower limit on EoS stiffness.

Heavy ion collision data impose an upper limit on EoS stiffness.

Combined constraints narrow down viable models of dense matter.

Abstract

Large neutron star masses as the recently measured $1.97\pm0.04$ M$_\odot$ for PSR J1614-2230 provide a valuable lower limit on the stiffness of the equation of state of dense, nuclear and quark matter. Complementary, the analysis of the elliptic flow in heavy ion collisions suggests an upper limit on the EoS stiffness. We illustrate how this dichotomy permits to constrain parameters of effective EoS models which otherwise could not be derived unambiguously from first principles.