Scale symmetry and composition of compact star matter

Abstract

The dense compact star matter is studied by using the skyrmion crystal approach. The chiral effective theory used includes the lightest scalar meson, the lowest-lying vector mesons as well as pions. Consistency with the vector manifestation and the dilaton limit fixed point at high density constrains the anomalous dimension of the gluon field $1.0\lesssim |{\gamma }_{G^2}|\lesssim 2.0$ and leads to the significance of the scale symmetry breaking in the intrinsic parity-odd part of the effective theory. The speed of sound $v_s^2\simeq 1/3$ and the polytropic index $\gamma \simeq 1$ -- both satisfy the conformal limits -- after the dilaton limit fixed point at high density but the matter is still in the hadronic phase. This means that neither the conformal speed of sound nor the smallness of the polytropic index can be used as a criterion of the onset of quark matter. These conclusions are significant for constructing the equation of state of nuclear matter.

6 pages, 5 figures

References in corpus (9)

• Sound velocity bound and neutron stars
• Towards Understanding Astrophysical Effects of Nuclear Symmetry Energy
• Compact stars with sequential QCD phase transitions
• Half-Skyrmions, Tensor Forces and Symmetry Energy in Cold Dense Matter
• Functional renormalization group studies of nuclear and neutron matter
• Quarkyonic stars with isospin-flavor asymmetry
• The Role of the Dilaton in Dense Skyrmion Matter
• Neutron stars with a crossover equation of state
• Vector dominance, one flavored baryons, and QCD domain walls from the "hidden" Wess-Zumino term

Cited by in corpus (3)

• Dense Matter in Neutron Stars with eXTP
• Topology and emergent symmetries in dense compact star matter
• Finite density nuclear matter and neutron stars in hard-wall AdS/QCD model