LOW-ENERGY M1 STRENGTH IN THE LI-7(P,GAMMA-O)BE-8 REACTION

The Li-7(p, gamma 0)Be-8 reaction is studied in a microscopic cluster model. All relevant subsystem properties are well reproduced. The calc ulated astrophysical S-factor is in good agreement with the experiment al data, although some M1 strength is missing in the 1(+); 1 resonance region, and there is no contribution from the 1(+);0 stare. Our model predicts, in contradiction to experiment, a dominant I = 1 channel sp in contribution to the cross section. We estimate an M1 strength of 3. 5% at 80 keV. By assuming the experimental resonance parameters and ch annel spin ratio for the first 1(+) state that M1 strength is 6.3%, in good agreement with an R-matrix analysis,