Low-lying resonances in the 16B nucleus

We investigate the 16B spectrum within a microscopic 15B + n model, involving several channels. The wave functions are defined in the Generator Coordinate Method, associated with the microscopic R-matrix formalism. We suggest that the narrow peak observed in recent experiments above the 15B + n threshold can be assigned to a 0− resonance which decays by d-wave neutron emission. The GCM calculation shows that this state cannot be reproduced in a single-channel B15(3/2−)+n model, and that excited configurations are necessary. Other 1− and 2−s-wave resonances are found at low excitation energies. In particular, we find a 1− state which represents a possible candidate for the 16B ground state. In general, our results show the importance of a multichannel framework. Comparisons with shell-model calculations are briefly discussed.