Hyperon Puzzle, Hadron-Quark Crossover and Massive Neutron Stars

Understand

Bulk properties of cold and hot neutron stars (NSs) are studied on the basis of the hadron-quark crossover picture where a smooth transition from the hadronic phase to the quark phase takes place at finite baryon density.

• By using a phenomenological equation of state (EOS) "CRover" which interpolates the two phases at around 3 times the nuclear matter density, it is found that the cold NSs with the gravitational mass larger than 2-solarmass can be sustained.
• This is in sharp contrast to the case of the first-order hadron-quark transition.
• The radii of the cold NSs with the CRover EOS are in the narrow range which is insensitive to the NS masses.