Analytical structure of the S matrix for the coupled channel problem d+t↔n+α and the interpretation of the Jπ=3/2+ resonance in 5He

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 5He(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 5He(3/2+) proves to be a coupled channel pole associated predominantly with the d-t system