Gamow–Teller matrix elements in light nuclei and (p,n) cross sections at Ep = 35 MeV

The (p,n) cross sections for the 0+→1+ excitation are studied experimentally at Ep=35 MeV in eight nuclei with Tz=(N−Z)/2=1, 14C, 18O, 22Ne, 26Mg, 30Si, 34S, 38Ar and 42Ca. It is found that the peak (p,n) cross sections around θ≈30° are proportional to the corresponding β+-decay rates of the Tz=−1 partners of the T=1 multiplets. We propose a prescription to extract GT matrix elements in light nuclei from (p,n) cross sections using such proportionality. The method is applied to determine an unknown B(GT) matrix element in 26Al, which is energetically inaccessible by β+-decay experiments.