Probing $\Xi N$ interaction through inversion of spin-doublets in $\Xi N \alpha \alpha$ nuclei

Abstract

A new way to study the spin-isospin dependence of the $\Xi N$ interaction is explored through the energy levels of $\Xi N\alpha$ and $\Xi N\alpha \alpha$ systems with $\alpha$ being a spectator to attract the $ \Xi N$ pair without changing its spin-isospin structure. By using the Gaussian expansion method (GEM) with the state-of-the-art $\Xi N$ potential obtained from lattice QCD calculations, it is found that $\Xi N\alpha \alpha$ has spin-doublet bound states with $J^{\pi}={1^-}$ and $2^-$ in both isospin triplet and singlet channels. The inversion of the $1^-$-$2^-$ spin-doublet between the iso-triplet and the iso-singlet is found to be strongly correlated with the relative strengths of the $\Xi N$ interaction in the $^{11}{\rm S}_0, ^{13}{\rm S}_1,^{31}{\rm S}_0$ and $^{33}{\rm S}_1$ channels. The $(K^-, K^+)$ and $(K^-,K^0)$ reactions on the $^{10}$B target are proposed to produce those bound states.