High-resolution study of Gamow-Teller transitions from the Tz=1 nucleus Ti46 to the Tz=0 nucleus V46

The Gamow-Teller (GT) transition strengths in fp-shell nuclei are important parameters in presupernova models. A high-energy-resolution (He3,t) experiment was performed on the Tz=1 nucleus Ti46 at 0° and at an intermediate incident energy of 140 MeV/nucleon for the study of precise GT transition strengths to the final Tz=0 nucleus V46. With an energy resolution of 33 keV, individual GT transitions were observed and GT strengths were derived for them up to the excitation energy of 4.5 MeV. The GT strengths were compared with shell-model calculations using various effective interactions. In this low-lying region, most GT states have isospin T=0. A few GT states with isospin T=1 were identified from the existence of the corresponding (analog) M1 states in Ti46. By comparing the GT strength with the corresponding (analogous) M1 transition strength studied in Ti46(e,e') or (γ,γ') measurements, a large constructive interference of orbital and spin terms was suggested for one of these M1 transitions. © 2006 The American Physical Society.