PUB - Publikationen an der Universität Bielefeld

We present two types of models for hybrid compact stars composed of a quarkcore and a hadronic mantle with an abrupt first order phase transition at theinterface which are in accordance with the latest astrophysical measurements oftwo 2 M_sun pulsars. While the first is a schematic one, the second one isbased on a QCD motivated nonlocal PNJL model with density-dependent vectorcoupling strength. Both models support the possibility of so called twincompact stars which have the same mass but different radius and internalstructure at high mass (~2 M_sun), provided they exhibit a large jump \Delta\epsilon in the energy density of the first order phase transition fulfilling\Delta \epsilon/\epsilon_crit > 0.6. We conclude that the measurement ofhigh-mass twin stars would support the existence of a first order phasetransition in symmetric matter at zero temperature entailing the existence of acritical end point in the QCD phase diagram.