  We discuss a hybrid equation of state (EoS) that fulfills constraints for
mass-radius relationships and cooling of compact stars. The quark matter EoS is
obtained from a Polyakov-loop Nambu--Jona-Lasinio (PNJL) model with color
superconductivity, and the hadronic one from a relativistic mean-field (RMF)
model with density-dependent couplings (DD-RMF). For the construction of the
phase transition regions we employ here for simplicity a Maxwell construction.
We present the phase diagram for symmetric matter which exhibits two remarkable
features: (1) a "nose"-like structure of the hadronic-to-quark matter phase
border with an increase of the critical density at temperatures below T ~ 150
MeV and (2) a high critical temperature for the border of the two-flavor color
superconducting (2SC) phase, T_c > 160 MeV. We show the trajectories of
heavy-ion collisions in the plane of excitation energy vs. baryon density
calculated using the UrQMD code and conjecture that for incident energies of 4
... 8 A GeV as provided, e.g., by the Nuclotron-M at JINR Dubna or by lowest
energies at the future heavy-ion collision experiments CBM@FAIR and NICA@JINR,
the color superconducting quark matter phase becomes accessible.
