Identification of analog states in the T=1/2 A=27 mirror system from low excitation energies to the region of hydrogen burning in the 26Alg,m(p,γ)27Si reactions

The reactions Al-26(g)(p,gamma)Si-27 and Al-26(m)(p,gamma)Si-27 are important for influencing the galactic abundance of the cosmic gamma-ray emitter Al-26(g) and for the excess abundance of Mg-26 found in presolar grains, respectively. Precise excitation energies and spin assignments of states from the ground state to the region of astrophysical interest in Si-27, including the identification and pairing of key astrophysical resonances with analog states in the mirror nucleus Al-27, are reported using gamma rays observed in the C-12 + O-16 fusion reaction. The detailed evolution of Coulomb energy differences between the states in Si-27 and Al-27 is explored, including the region above the astrophysical reaction thresholds.