Simultaneous measurement of beta-delayed proton and gamma emission of P-26 for the Al-25 (p , gamma) Si-26 reaction rate

The beta decay of P-26 was used to populate the astrophysically important E-x = 5929.4(8) keV, J(pi) = 3(+) state of Si-26. Both beta-delayed protons at 418(8) keV and gamma rays at 1742(2) keV emitted from this state were measured simultaneously for the first time, and the corresponding absolute intensities have been estimated as 11.1(12)% and 0.59(44)%, respectively. The half-life of P-26 has been determined to be 43.6(3) ms, which is in good agreement with previous experimental results. Besides, shell-model calculations with weakly bound effects were performed to investigate the decay properties of other resonant states and a spin-parity of 4(+) rather than 0(+) is favored for the E-x = 5945.9(40) keV state. Combining the experimental results and theoretical calculations, the Al-25(p, gamma)Si- 26 reaction rate in explosive hydrogen burning environments was calculated. The new determined total reaction rate is consistent with previous studies at T > 0.2 GK.