Effective range analysis of s- and d-wave α-α scattering

Abstract

The new Q-value E r and width Γ of the 8Be ground state as determined in ref. 1) have been analysed with the low-energy α-α s-wave phase shifts δ 0 to determine the effective range expansion parameters of the phase shift δ 0. Use of these parameters gives better limits on Γ than the direct experimental ones quoted in ref. 1). The maximum of δ 0 as a function of the centre-of-momentum energy is calculated to be very close to 180° but does not exceed this value. The order of magnitude of δ 2 in this energy region is estimated on the basis on an effective-range analysis for l = 2; it is seen that δ 2 is negligible.