A dual description of quarks and baryons: Quarkyonic matter within a relativistic quark model

Abstract

We investigate quarkyonic matter within a relativistic quark model by combining the dual quarkyonic picture with the quark-meson coupling (QMC) model. Using relativistic gaussian quark wavefunctions for the nucleon, we construct the quarkyonic QMC (QQMC) model and study the properties of symmetric nuclear matter and pure neutron matter. We find that the quark saturation density depends sensitively on the nucleon size parameter and that nuclear interactions quantitatively modify the high-density behavior of the equation of state (EoS) and the sound velocity. In particular, the QQMC model yields an earlier onset of quark saturation than the noninteracting gaussian quarkyonic (GQ) model, indicating that nuclear interactions enhance the stiffening of the EoS in the quarkyonic regime.

Figures (4)

• Figure 1: Quark and nucleon momentum-space distributions, $f_{Q}(q)$ and $f_{N}(k=qN_{c})$, in symmetric nuclear matter (SNM) for the case of $r_{p}=0.7$ fm using the quarkyonic QMC (QQMC) model. Above $\rho_{\rm sat}$, $f_{Q}(q)$ is supposed to be the shifted distribution to describe that the low momentum levels of quarks are fully occupied, as discussed in Ref. PhysRevD.104.074005.
• Figure 2: Density dependence of nucleon bulk and shell momenta, $k_{b}^{\ast}$ and $k_{s}^{\ast}$, in the quarkyonic QMC (QQMC) model.
• Figure 3: Binding energy per nucleon, $\varepsilon_{b}=\varepsilon_{\rm tot}/\rho_{N}-M_{N}$, as a function of baryon density ratio, $\rho_{N}/\rho_{0}$, in the QMC and QQMC models.
• Figure 4: Sound velocity, $v_{s}^{2}$, as a function of baryon density ratio, $\rho_{N}/\rho_{0}$, for $r_p=0.6$, $0.7$, and $0.8$ fm in the QQMC and GQ models.