Nuclear structure in Parity Doublet Model

Using an extended parity doublet model with the hidden local symmetry, we study some properties of nuclei in the mean field approximation to see if the parity doublet model could reproduce nuclear properties and also to estimate the value of the chiral invariant nucleon mass $m_0$ preferred by nuclear structure. We first determine our model parameters using the inputs from free space and from nuclear matter properties. Then, we study some basic nuclear properties such as the nuclear binding energy with several different choices of the chiral invariant mass. We observe that our results approach the experimental values as $m_0$ is increased until $m_0=700$ MeV and start to deviate more from the experiments afterwards with $m_0$ larger than $m_0=700$ MeV. From this observation, we conclude that $m_0=700$ MeV is preferred by nuclear properties. We then calculate some properties of several selected nuclei with $m_0=700$ MeV and compare them with experiments. Finally, we study the neutron-proton mass difference in some nuclei.