Color superconducting quark matter in compact stars

TL;DR

This paper demonstrates that modern quantum field theories including color superconductivity can model hybrid stars consistent with recent neutron star mass and radius observations, and discusses implications for future quark matter detection.

Contribution

It introduces a microscopic description of hybrid stars with color superconductivity that aligns with new astrophysical constraints and explores diagnostic tools for quark matter detection.

Findings

Color superconductivity is essential for modeling cooling in hybrid stars.

Hybrid stars can meet constraints from high mass and large radius observations.

Neutrino untrapping transition affects energy release and star appearance.

Abstract

Recent indications for high neutron star masses (M \sim 2 M_sun) and large radii (R > 12 km) could rule out soft equations of state and have provoked a debate whether the occurence of quark matter in compact stars can be excluded as well. We show that modern quantum field theoretical approaches to quark matter including color superconductivity and a vector meanfield allow a microscopic description of hybrid stars which fulfill the new, strong constraints. For these objects color superconductivity turns out to be an essential ingredient for a successful description of the cooling phenomenology in accordance with recently developed tests. We discuss the energy release in the neutrino untrapping transition as a new aspect of the problem that hybrid stars masquerade themselves as neutron stars. Quark matter searches in future generations of low-temperature/high-density nucleus-nucleus collision experiments such as low-energy RHIC and CBM @ FAIR might face the same problem of an almost crossover behavior of the deconfinement transition. Therefore, diagnostic tools shall be derived from effects of color superconductivity.