Resonant states 0+ of the Boron isotope 8B from the Jost-matrix analysis of the partial cross-sections

Abstract

The available [Formula: see text]-matrix parametrization of experimental data on the excitation functions for the elastic and inelastic [Formula: see text] scattering at the collision energies up to 3.4[Formula: see text]MeV is used to generate the corresponding partial-wave cross-sections in the states with [Formula: see text]. Thus, obtained data are fitted using the semi-analytic two-channel Jost matrix with a proper analytic structure and some adjustable parameters. Then the spectral points are sought as zeros of the Jost matrix determinant (which correspond to the [Formula: see text]-matrix poles) at complex energies. The correct analytic structure makes it possible to calculate the fitted Jost matrix on any sheet of the Riemann surface whose topology involves not only the square-root but also the logarithmic branching caused by the Coulomb interaction. In this way, two overlapping [Formula: see text] resonances at the excitation energies [Formula: see text] and [Formula: see text][Formula: see text]MeV have been found.