Reanalysis of α+α scattering and the β-delayed α spectra from 8Li and 8B decays -: art. no. 055502

We reanalyzed the Wilkinson-Alburger delayed-alpha spectra from Li-8 and B-8 decay, accounting for lepton-recoil broadening that had been neglected in previous analyses. This substantially improved the quality of the fits. The Li-8 and B-8 delayed-alpha spectra are now consistently described by the same Be-8 final-state continuum. In our analysis, which did not invoke a low-lying intruder state, the discrepancy between the final-state continua inferred from the delayed-alpha spectra and from the L=2 alpha+alpha phase shifts is much less than found by previous authors. This largely resolves discrepancies noted by Barker and Warburton; the remaining differences may be artifacts of the assumption that the beta-decay matrix elements are independent of excitation energy. Our analysis of the Wilkinson-Alburger data is consistent with results from the recent coincidence study of Ortiz , which gives additional confidence in using delayed-alpha spectra to infer the spectrum of B-8 neutrinos that dominate the counting rate of many solar neutrino detectors.