The Gamow-Teller (GT) transition is a powerful tool to study nuclear structure because of its simple form of the operator στ. The structure of 26Al is studied through Gamow-Teller transitions using nuclear charge-exchange reaction. The reaction 26Mg(3He,t)26Al was performed at an incident energy of 140 MeV/nucleon and scattering angle at and near 0˚. The energy resolution of ΔE = 22 keV allowed us to study many discrete states. Most of the prominent states are suggested that they are excited with ΔL = 0 GT transitions. The GT states were studied up to 18.5 MeV. For the extraction of the B(GT) value, the proportionality between cross section and B(GT) was used. The standard B(GT) values were obtained from the 26Si beta decay, where the mirror symmetry of B(GT) was obtained. The T = 2 GT states are expected in the region Ex ≥ 13.5 MeV. By comparing with the results of 26Mg(t, 3He)26Na reactions, the isospin symmetry of T = 2 GT states is discussed. Due to the high-energy resolution, the decay widths Γ for the states in the Ex > 9 MeV region could be studied. The narrow width of the T = 2 states at 13.592 MeV is explained in terms of isospin selection rules.

In order to study the T z = +1 → 0 Gamow-Teller (GT) transitions in the mass A = 26 system, a chargeexchange reaction 26 Mg( 3 He,t) 26 Al was performed at an incident energy of 140 MeV/nucleon and scattering angle at and near 0• , where T z is the z component of isospin T defined by (N − Z)/2. In this (p,n)-type reaction, it is expected that GT states with T = 0, 1, and 2 are excited. An energy resolution of E = 23 keV allowed us to study many discrete states. Most of the prominent states showed 0• -peaked angular distributions, which suggested that they are the states excited by L = 0 GT transitions. Candidates of GT states were studied up to an excitation energy E x = 18.5 MeV. The reduced GT transition strengths, B(GT), were derived assuming the proportionality between cross sections and B(GT) values. Standard B(GT) values were obtained form the 26 Si β decay, where the mirror symmetry of T z = ±1 → 0 GT transitions was assumed. The GT strength, as a whole, is divided in two energy regions: the region of up to 8.5 MeV and the higher-energy region of 8.5-12.8 MeV, where the strength in the latter region distributed like a resonance. The obtained GT strength distribution is compared with the results of random phase approximation calculations. The T = 2 GT states are expected in the region E x 13.5 MeV. By comparing with the results of (n,p)-type 26 Mg(d, 2 He) 26 Na and 26 Mg(t, 3 He) 26 Na reactions, the isospin symmetry of T = 2 GT states is discussed. Owing to the high-energy resolution, we could study the decay widths for the states in the E x > 9 MeV region. The T = 2 state at 13.592 MeV is not noticeably wider than the experimental energy resolution. The narrow width of the state is explained in terms of isospin selection rules.