Delayed Alpha Spectra from the Beta Decay of 8Li and 8B

Abstract

Many-level R-matrix fits are made to the ()(-()( scattering d-wave phase shift and to ()(-spectra from BLi and BB ,8-decay measured by Wilkinson and Alburger (1971). With the requirement that the parameter values are the same in the fits to the phase shift and the ()(-spectra data, the best overall fits are obtained for a channel radius of about 6�5 fm, implying a broad 2+ intruder state of BBe at about 9 MeV. There is satisfactory agreement between the Gamow-Teller matrix elements extracted from the fits and shell model values.