The reaction 3 He + 11 B → d + 12 C * has been used to populate resonances in 12 C up to an excitation energy of 15 MeV. The subsequent breakup to three α particles has been measured in complete kinematics. Dalitz plots are used to visualize and analyze the data. The Dalitz plot intensity distribution exhibits zero points characteristic of the total spin and parity of the 3α system allowing us to determine the spin and parity of a state in 12 C at 13.35 MeV whose quantum numbers were hitherto not well established. The Dalitz plot intensity distributions of the 2 − state at 11.83 MeV and the 1 + state at 12.71 MeV are compared with the predictions of a recent three-body calculation as well as with simpler models. All are able to reproduce the gross structures seen in the Dalitz plot, but none give an accurate description of the detailed profile of the distributions.

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The proton-rich nucleus 33 Ar has been studied by detailed proton and γ-ray spectroscopy at the low-energy facility of SPIRAL at GANIL. Proton and γ-ray singles and coincidence measurements allowed to establish a quasi complete decay scheme of this nucleus. By comparing the proton intensity to different daughter states, tentative spin assignments have been made for some of the states of 33 Cl. The Gamow-Teller strength distribution is deduced and compared to shell-model calculations and a quenching factor is determined. States close to the isobaric analogue state are searched for with respect to isospin mixing.PACS numbers: 21.10.-k Properties of nuclei, 23.50.+z Decay by proton emission, 29.30.Ep Charged-particle spectroscopy

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