Study on the ${22}_{22}^{++}$ Resonance in ⁶He via Analysis of ⁶He($pp$, $p{p}^{\prime }$) Reactions

${}^6$He is known as two-neutron halo nuclei and has a Borromean structure in which there is no bound state in the binary subsystems. To explore resonances of unstable nuclei, the (p, $p^{\prime }$) reaction with the inverse kinematics has been often used. The $2_2^{+}$ state has been investigated via various structural calculations and experimental studies. Unfortunately, the contribution of this state in the energy spectrum does not show a shape structure. Thus, the resonant energy and decay width of the $2_2^{+}$ state have never been clear. To clarify the properties, it is required an accurate analysis of treating not only resonant contributions but also nonresonant contributions in energy spectra. In this study, we investigated the $2_2^{+}$ resonant state via the analysis of ${}^6$He(p, $p^{\prime }$) reaction by using the continuum-discretized coupled-channels method. To describe the resonant and nonresonant state components, we also applied the complex scaling method to the analysis.