Properties of the intermediate structure in 41Sc

Nuclear resonance structures having widths intermediate to those of compound nucleus states and single-particle states were first proposed as early as 1963. Closed shell nuclei represent the best place to test states of simple structure, so that nuclei such as 41Sc are attractive candidates for such studies. Possible intermediate structure was reported in 1974 when a cluster of seven resonances, centered about an excitation energy of 7.2 MeV in 41Sc, was observed to preferentially decay to the 3- excited state in 40Ca. We have measured angular correlations in the 40Ca(p,p'γ)40Ca* (3.73 MeV) reaction for many of the levels in this cluster, and, in addition, we have measured analyzing power in the elastic channel between E/sub p/ = 6.0 and 6.4 MeV. These measurements determined J/sup π/ = 5/2+ for the spin of 6 of the resonances which preferentially decay to the 1p-1h 3- state in 40Ca. In order to determine the decay properties of member resonances, analyzing powers, cross sections, spin-flip asymmetries, and spin-flip probabilities have been measured in the inelastic channel for two of the strongest resonances in this structure. The resonance at E/sub p/ = 6.18 MeV was found to decay to the 3- state in 40Ca be early pure p/sub 1/2/ decay, while the decay of the other strong resonance at E/sub p/ = 6.28 MeV was found to be a mixture of about 80% p/sub 1/2/ and 20% p/sub 3/2/ decay to the 3- state. These results are interpreted as being evidence for a 2p-1h intermediate structure in 41Sc formed by the coupling of a 2p proton to the 3- state in 40Ca. This result further implies that the 3- state in 40Ca is a complex state with both lp-1h configurations and a collective component