High-resolution study of 56Fe→56Mn Gamow-Teller transition by the combined analysis of 56Fe(3He, t)56Co and 56Fe(P, p')56Fe reactions

The Gamow-Teller (GT) transitions in the β+(electron capture) direction from the ground state of 56Fe to the excited states of 56Mn play an important role in the core collapse of presupernova. Assuming that isospin analogous transitions in isobars have corresponding strengths, we deduced these GT strengths by combining the results of the 56Fe(p, p')56Fe experiment performed at 200 MeV and 0 deg. and the 56Fe(3He, t)56Co experiment in the ββ direction at 140 MeV/u and 0 deg. The ground state of 56Fe has the isospin value of T = 2, while the GT states in 56Mn have T = 3. In order to identify the analogous T = 2→3, GT transitions in the 56Fe(p, p')56Fe and the 56Fe(3He, t)56Co measurements, we used the fact that the isospin Clebsch-Gordan (CG) coefficients for these T = 2→3 transitions are different in these measurements. Then the GT transition strengths B(GT) in the β+ direction can be deduced from the B(GT) values of the corresponding transitions well determined in the 56Fe(3He, t)56Co measurement assuming the isospin symmetry and correcting the difference of CG coefficients.