Hadron-Quark Crossover and Massive Hybrid Stars. (arXiv:1212.6803v1 [nucl-th])

Hadron-Quark Crossover and Massive Hybrid Stars. (arXiv:1212.6803v1 [nucl-th]):
On the basis of the percolation picture from the hadronic phase with hyperons
to the quark phase with strangeness, we construct a new equation of state (EOS)
with the pressure interpolated as a function of the baryon density. The maximum
mass of neutron stars can exceed $2M_{\odot}$ if the following two conditions
are satisfied; (i) the crossover from the hadronic matter to the quark matter
takes place at around three times the normal nuclear matter density, and (ii)
the quark matter is strongly interacting in the crossover region. This is in
contrast to the conventional approach assuming the first order phase transition
in which the EOS becomes always soft due to the presence of the quark matter at
high density. Although the choice of the hadronic EOS does not affect the above
conclusion on the maximum mass, the three-body force among nucleons and
hyperons plays an essential role for the onset of the hyperon mixing and the
cooling of neutron stars.