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In order to study the Gamow-Teller (GT) transitions from the Tz = +2 nucleus 44Ca to the Tz = +1 nucleus 44Sc, where T. is the z component of isospin T, we performed the (p, n)-type (³He, t) charge-exchange (CE) reaction at 140 MeV/nucleon and the scattering angles 0 and 2.5°. An energy resolution of 28 keV, that was realized by applying matching techniques to the magnetic spectrometer system, allowed the study of fragmented states. The GT transition strengths, ß(GT), were derived up to the excitation energy (Ex) of 13.7 MeV assuming the proportionality between cross sections and ß(GT) values. The total sum of ß(GT) values in discrete states was 3.7, which was 31 % of the sum-rule-limit value of 12. Shell model calculations using the GXPF1J interaction could reproduce the gross features of the experimental /Í(GT) distribution, but not the fragmentation of the strength. By introducing the concepts of isospin, properties of isospin analogous transitions and states were investigated, (i) Assuming isospin symmetry, the Tz = +2 → +1 and Tz = -- 2 → --1 mirror GT transitions should have the same properties, where the latter can be studied in the ß decay of ""Cr to 44V. First, we confirmed that the /i-decay half-life T\ß of44Crcan be reproduced using the ß(GT) distribution from theCaHe, t) measurement. Then, the 0°, ('He, t) spectrum was modified to deduce the "/i-decay spectrum" and it was compared with the delayed-proton spectrum from the 44Cr ß decay. The two spectra were mostly in agreement for the GT excitations, but suppression of the proton decay was found for the T = 2 isobaric analog state (IAS), (ii) Starting from the T = 2 ground state of 44Ca, the (3He, t) can excite GT states (state populated by GT transitions) with 7 = 1, 2, and 3. On the other hand, the uCa(p, p') reaction can excite spin-Ail states (states populated by spin-Mi transitions) with T = 2 and 3 that are analogous to the T = 2 and 3 GT states, respectively. By comparing the spectra from these two reactions, a T value of 2 is suggested for several GT states in the Ex = 11.5-13.7 MeV region, (iii) It has been suggested that the T = 2, Jπ = 0+ double isobaric analog state (DIAS) at 9.338 MeV in the Tz = 0 nucleus 44Ti forms an isospin-mixed doublet with a subsidiary 0+ state at 9.298 MeV. Since no corresponding state was found in the Tz = +1 nucleus 44Sc, we suggest 7=0 for the subsidiary state. [ABSTRACT FROM AUTHOR]

In this work we have studied Tz=+2→+1, Gamow-Teller (GT) transitions in the 48Ti(³He,t)48V charge-exchange reaction at 140 MeV/nucleon and 0° at the Research Center for Nuclear Physics, Osaka. From the high-resolution facility, consisting of a high-dispersion beamline and the Grand Raiden spectrometer, the spectrum had an energy resolution of 21 keV, among the best achieved. Individual GT transitions were observed and GT strength was derived for each state populated up to an excitation energy of 12 MeV. The total sum of the B(GT) strength observed in discrete states was 4.0, which is 33% of the sum-rule-limit value of 12. The results were compared with the results of shell-model calculations carried out with the GXPF1J interaction. The measured B(GT) distribution was also compared with that obtained in the (³He,t) charge-exchange reaction on 47Ti. On the assumption of isospin symmetry the β spectrum of the Tz=-2 nucleus Fe48 was deduced from the observed spectrum in the 48Ti(³He,t)48V reaction and this predicted spectrum was compared with the measured one. [ABSTRACT FROM AUTHOR]