Gamow-Teller transitions in pf-shell nuclei studied in (3He, t) reactions

The Gamow-Teller transition strengths in pf -shell nuclei are important parameters in a presupernova model. A high resolution ( 3 He, t ) reaction was performed from T z = + 1 nuclei ( 42 Ca, 46 Ti, 50 Cr and 54 Fe) to T z = 0 nuclei ( 42 Sc, 46 V, 50 Mn and 54 Co) at an incident energy of 140 MeV/nucleon and at 0°for the precise study of GT transition strengths B (GT). To derive B (GT) values for these pf -shell nuclei, the R 2 value, the ratio between the GT and Fermi unit cross sections, was introduced. The R 2 values were studied for various mass nuclei by using the B (GT) values from β -decay studies as standard, and the mass dependence was derived. It was found that GT strengths in these four pf -shell nuclei move to higher excitation energies as the mass numberA increases. The obtained GT strength distributions were compared with shell model calculations.