In-medium properties of the low-lying strange, charm, and bottom baryons in the quark-meson coupling model

In-medium properties of the low-lying strange, charm, and bottom baryons in symmetric nuclear matter are studied in the quark-meson coupling (QMC) model. Results for the Lorentz-scalar effective masses, mean field potentials felt by the light quarks in the baryons, in-medium bag radii, and the lowest mode bag eigenvalues are presented for those calculated using the updated data. This study completes the in-medium properties of the low-lying baryons in symmetric nuclear matter in the QMC model, for the strange, charm and bottom baryons which contain one or two strange, one charm or one bottom quarks, as well as at least one light quark. Highlight is the prediction of the bottom baryon Lorentz-scalar effective masses, namely, the Lorentz-scalar effective mass of $\Sigma_b$ becomes smaller than that of $\Xi_b$ at moderate nuclear matter density, $m^*_{\Sigma_b} < m^*_{\Xi_b}$, although in vacuum $m_{\Sigma_b} > m_{\Xi_b}$. We study further the effects of the repulsive Lorentz-vector potentials on the excitation (total) energies of these bottom baryons.

K. Tsushima · 2018