Speaker
Description
High-precision experiments of $p$-shell hypernuclear production have been successfully carried out at the Jefferson Laboratory (JLab), disclosing novel excited states. As one of the next advanced experiments, $_{\Lambda}^{40,48}$K production experiments are being planned. These experiments focus on the interaction between a $\Lambda$ hyperon and nucleons in a neutron-rich environment, and therefore it is interesting to know how the isospin dependence is reflected in the energy spectra and production cross sections.
In order to understand the detailed structure of cross sections producing typical $p$-shell hypernuclei, we have extended a shell-model space in which both positive- and negative-parity nuclear states are coupled with hyperon states. In fact this approach succeeded in explaining new extra subpeaks for the first time as well as the pronounced peaks in a consistent way.
In this presentation, we apply the extended shell-model to the analysis of $_{\Lambda}^{40,48}$K and evaluate DWIA spectra of $(\gamma,K^{+})$ reactions, which correspond to the $(e, e' K^{+})$ reaction experiments planned at JLab. Furthermore, we take into account the $\Lambda N$-$\Sigma N$ mixing effect and discuss how the isospin dependence of the $\Lambda N$-$\Sigma N$ mixing affects the hypernuclear energy spectra and production cross sections.
