Largely deformed states of ${}^{13}$B

Abstract

The excited states of ${}^{13}$B were studied with a method of antisymmetrized molecular dynamics(AMD). The theoretical results suggest that the intruder states with large deformations construct the rotational bands, $K^{\pi }=3/2^{-}$ and $K^{\pi }=1/2^{+}$, starting from 5 MeV and 8 MeV, respectively. The neutron structure of the $K^{\pi }=3/2^{-}$ is analogous to the intruder ground state of ${}^{12}$Be. In the predicted $K^{\pi }=1/2^{+}$ band, we found very exotic structure with a proton intruder configuration. This proton intruder state has a larger deformation than superdeformation. The band-head $1/2^{+}$ state is assigned to the $1/2^{+}$(4.83 MeV), which was experimentally suggested to be the proton intruder state because of the strong production via the proton-transfer to the ${}^{12}$Be($0^{+}$) state in the ${}^4$He(${}^{12}$Be,${}^{13}$B$\gamma$)$X$ experiments.

Comments: 4 figures, submitted to Phys. Rev. C