ISOSPIN SYMMETRY OF T_z = ±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 37 Cl (3 He ,t)37 Ar and 41 K (3 He ,t)41 Ca reactions at E beam = 140 MeV / nucleon . The GT transition strengths in 37 Ar and 41 Ca 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 37 Ca and 41 Ti , 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.