Phase diagram determination at fivefold nuclear compression

In the standard model of particle physics, the strong force is described by the theory of quantum chromodynamic (QCD). Based on QCD properties, it is commonly believed that at sufficiently high temperatures or densities, the hadrons are melted into their constituent quarks, i.e., undergo a deconfinement transition to a new phase of quarks and gluons. Such phase is frequently called quark matter or quark-gluon plasma (QGP). Although QGP has been observed in relativistic heavy-ion collisions, it is currently an open question about the onset of deconfinement. By comparing simulations from a reliable hadron and quark relativistic transport model and recent STAR experimental data, we infer that the onset of hadron-quark phase transition occurs at about fivefold nuclear compression corresponding temperature $T\sim$ 112 MeV and baryon chemical potential $\mu_{B}\sim$ 586 MeV in nuclear matter phase diagram. This finding has important implications for the studies of early and present universe, such as relevant to the fraction of dark matter formed in early universe and structure of neutron stars as well as the dynamics of neutron star mergers.
Comment: 12 pages, 4 figures