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

The β decay of P26 was used to populate the astrophysically important Ex=5929.4(8) keV, Jπ=3+ state of Si26. Both β-delayed protons at 418(8) keV and γ 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 P26 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 Ex=5945.9(40) keV state. Combining the experimental results and theoretical calculations, the Al25(p,γ)Si26 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.