Neutron stars with crossover to color superconducting quark matter
D. Blaschke, E.-O. Hanu, Simon Liebing
Abstract
We follow the idea that the QCD phase diagram may be described by a crossover from a hadron resonance gas to perturbative QCD using the switch function ansatz of Albright, Kapusta, and Young [Phys. Rev. C 90, 024915 (2014)]. While the switch function could be calibrated at vanishing baryon chemical potential with data from lattice QCD simulations, it has been suggested recently by Kapusta and Welle [Phys. Rev. C 104, L012801 (2021)] that in the zero temperature limit, the switch function parameter ${\ensuremath{\mu}}_{0}$ could be constrained by neutron star phenomenology, in particular by massive pulsars such as PSR $\text{J0740}+6620$ with a mass exceeding $2\phantom{\rule{0.16em}{0ex}}{M}_{\text{sun}}$. In this work we demonstrate that this procedure to constrain the QCD phase diagram does crucially depend on the fact that cold dense quark matter is very likely in a color superconducting state.