Tz = -1 → 0 β decays of 54Ni, 50Fe, 46Cr, and 42Ti and comparison with mirror (³He,t) measurements.

We have studied the β decay of the Tz = -1, f7/2 shell nuclei 54Ni, 50Fe, 46Cr, and 42Ti produced in fragmentation reactions. The proton separation energies in the daughter Tz = 0 nuclei are relatively large (≈4-5 MeV) so studies of the γ rays are essential. The experiments were performed at GSI as part of the Stopped-beam campaign with the RISING setup consisting of 15 Euroball Cluster Ge detectors. From the newly obtained high precision β-decay half-lives, excitation energies, and β branching ratios, we were able to extract Fermi and Gamow-Teller transition strengths in these β decays. With these improved results it was possible to compare in detail the Gamow-Teller (GT) transition strengths observed in beta decay including a sensitivity limit with the strengths of the Tz = +1 to Tz = 0 transitions derived from high resolution (³He,t) reactions on the mirror target nuclei at RCNP, Osaka. The accumulated B(GT) strength obtained from both experiments looks very similar although the charge exchange reaction provides information on a broader energy range. Using the "merged analysis" one can obtain a full picture of the B(GT) over the full Qβ range. Looking at the individual transitions some differences are observed, especially for the weak transitions. Their possible origins are discussed. [ABSTRACT FROM AUTHOR]