Neutron stars with crossover to color superconducting quark matter

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, 021915 (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 mu(0) could be constrained by neutron star phenomenology, in particular by massive pulsars such as PSR J0740+6620 with a mass exceeding 2 M-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.

Automated summary

This research demonstrates that the procedure to constrain the QCD phase diagram crucially depends on the fact that cold dense quark matter is very likely in a color superconducting state.