The role of pions on finite nuclei with relativistic chiral mean field model

We present a relativistic chiral mean field (RCMF) model, which is a method for proper treatment of pion-exchange interaction in the nuclear-many body problem. There the term of the pionic correlation is expressed in 2-particle 2-hole (2p-2h) states with particle-hole having pionic quantum number $J^{\pi} = 0^{1}, 1^{+}, 2^{-}, 3^{+}$,...to describe the full strength of the pionic correlation in the intermediate- and long-ranged region (r $>$ 0.5 fm). We include further the effect of the short-range repulsion in terms of the unitary correlation operator method (UCOM) for the central part of the pion-exchange interaction. We apply this model to $^{4}$He, $^{12}$C, and $^{16}$O nuclei. Pion plays an important role on the formation of the jj-magic shell structure by the Pauli-blocking mechanism of the pion- exchange interaction. The lowest pionic quantum number, $J^{\pi} = 0^{-}$, is the dominant component for construction of the surface structure. We also discuss chiral symmetry in finite nuclei in the linear sigma model.