Collective structure of negative parity states in ⁴²Ca

Proton- gamma ray angular correlations and Doppler shifts have been measured in the ³⁹K( alpha ,p gamma ) reaction at E_alpha =14 and 15 MeV. Spin-parity assignments and lifetimes were obtained for the following levels: E_x=6140 keV, J^pi =6^-, tau =70_-20⁺³⁰ fs; E_x=4896 keV, J^pi =5^-, tau =64+or-30 fs; E_x=4353 keV, J^pi =4^-, tau =550+or-150 fs; E_x=4099 keV, tau =730_-110⁺¹⁴⁰ fs; E_x=4045 keV, tau =250+or-85 fs. A total of five enhanced E2 transitions has been observed from these levels. The results are interpreted in terms of collective models.