Jonathan Carroll

University of Adelaide, Australia

QMC as a model of dense matter: from finite nuclei to hybrid stars

The QCD phase diagram at {μ > 0,T ≥ 0} is largely unknown and particularly inaccessible to even lattice QCD simulations. One method for investigating the μ >> 0 region is effective field theory using mean-field meson potentials. The EMC effect indicates that the quark structure of the nucleon is modified in an essential way in a nuclear medium, and the Quark-Meson Coupling (QMC) model provides a simple yet very successful description of meson-baryon interactions with feedback to the quark structure of the baryons. With QMC predictions for finite nuclei -- and, in particular, finite hypernuclei -- proving accurate, our attention turns to the equation of state of dense matter and the structure of 'hybrid stars'; neutron stars with proportions of hyperonic- or quark-matter. Using such an equation of state as an input to the Tolman-Oppenheimer-Volkoff equation allows us to construct models of stars and compare predicted mass and radius with pulsar observations. I will discuss the origins and predictions of QMC ranging from finite nuclei to hybrid stars and our recent progress in extending this model beyond the mean-field approximation to Hartree--Fock.

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