α+α scattering in a microscopic model with monopolar distortion

The feasibility of general generator coordinate method calculations with monopolar specific distortion is investigated on α+α scattering. A triple integral transform of matrix elements calculated with Slater determinants eliminates spurious center-of-mass components and uniformizes the basis functions of the relative motion. Besides the α-particle ground state, the ${\mathrm{\alpha }}^{\mathrm{*}}$ breathing mode and two pseudostates are included in the calculation. Collision matrices are determined up to 400 MeV with the microscopic R-matrix method. Different types of resonances and the α+${\mathrm{\alpha }}^{\mathrm{*}}$ inelastic cross section are discussed. The nature of Pauli resonances, i.e., resonances related to almost forbidden states and their relation with the Levinson theorem are investigated in a single-channel approximation.