Isospin symmetry of Tz=±3/2 → ±1/2 Gamow-Teller transitions in A=37 and A=41 nuclei

Under the assumption of good isospin symmetry, Tz=±3/2 → ±1/2 Gamow-Teller (GT) transitions in a mass A isobar are analogous, where Tz is the z component of isospin T defined by 1/2(N - Z). We studied the Tz=+3/2 → +1/2 GT transitions by using the 37Cl(3He,t)37Ar and 41K(3He,t)41Ca reactions at Ebeam=140 MeV/nucleon. The GT transition strengths in 37Ar and 41Ca were obtained up to the excitation energy (Ex) of 14.2 MeV and 10.4 MeV with energy resolutions of 30 and 35 keV, respectively. The obtained GT strengths were compared with those of the Tz=-2/3 → -1/2 mirror transitions, measured by the β-decay of 37Ca and 41Ti, respectively. It was found that the overall distributions of the mirror transitions were similar in both A=37 and A=41 systems. In A=37 the differences seen at lower excitation energies are suggested to be the effect of the tensor interaction in the charge-exchange reaction. The differences seen at higher excitation energies are suggested to be the effect of the Coulomb interaction that can break the mirror symmetry of the strength distributions. (author)