Study of the giant Gamow-Teller resonance in nuclear β-decay: The case of Ar-32

Abstract

Delayed proton and gamma emissions following the β-decay of Ar-32 have been studied. The half-life of Ar-32 is 98 ± 2 ms, and the T = 2 analogue state in Cl-32 lies at the excitation energy 5036 ± 12 keV. From the intensity of the feeding to this state the proton intensities can be converted to an absolute scale leading to a total proton branching ratio of (43 ± 3)%. From proton-gamma coincidence measurements it emerges that (1.9 ± 0.2)% of the protons lead to the first-excited state in S-31. A level scheme up to 8.75 MeV excitation in Cl-32 has been constructed and the Gamow-Teller strength function has been deduced. The result is a renormalization of the axial-vector strength to (49 ± 5)% of the free-nucleon value.