Orateur
Description
Using the axially deformed relativistic Hartree-Fock-Bogoliubov (D-RHFB) model, we explore the mechanism that triggers the novelties in $^{11}$Be, i.e., the parity inversion and one-neutron halo which are well reproduced by the RHF Lagrangian PKA1. Following the evolution from spherical to large prolate shapes, it is illustrated that the evidently enhanced $\pi$-pseudo-vector ($\pi$-PV) and $\rho$-tensor ($\rho$-T) couplings in PKA1 are crucial for correctly describing even-parity ground state (GS) of $^{11}$Be. By fragmentizing the even-parity orbit 1/2$_{\mskip 2mu 2}^{\mskip 1mu +}$, it is shown that the main fragment $1d_{5/2}$ strengthens the couplings with nuclear core to promise the even-parity GS, in which the $\rho$-T and $\pi$-PV couplings play an important role, and the other major one $2s_{1/2}$ remains weakly bound to form the halo in $^{11}$Be. Furthermore, it is found that the attractive inherent correlations between the $2s_{1/2}$ and $1d_{5/2}$ fragments are essential not only in determining the parity inversion but also in stabilizing the one-neutron halo of $^{11}$Be. Thus, an apparent picture of the deformed halo is achieved, which paves an efficient way to clarify the underlying mechanism responsible for the halos and other novelties in deformed unstable nuclei.
