Analytical structure of theSmatrix for the coupled channel problemd+t⇆n+α and the interpretation of theJπ=3/2+resonance inHe5

Using a resonance coupled channel model that provides a good description of the experimental data on the reaction d+t⇆n+α and d-t elastic scattering in the region of the resonance ${}_{}{}^5{}_{}{}^{}\mathrm{He}$(3/$2^{+}$), we find the disposition of the S-matrix poles on the different Riemann sheets. An investigation of the motion of the poles with variation of the coupling strengths reveals the structure of the resonant state. The role of scattering and confined channels in the formation of the physical resonance is considered with the use of the probability sum rule for the confined channel. We demonstrate that the resonance ${}_{}{}^5{}_{}{}^{}\mathrm{He}$(3/$2^{+}$) proves to be a coupled channel pole associated predominantly with the d-t system.