Angular momentum quasiparticle approach to cluster states in nuclei

Quasi-Free (p vector, 2p) reactions at medium energies are considered. In this context, a simple and rather direct method to extract informations about cluster correlations in nuclei is presented. It is shown that, if the initial nucleus has a nonvanishing spin, the effective polarization for a knock-out leading to a given final state can be expressed as a linear combination of effective polarizations defined in the basis of an angular momentum quasiparticle approach to cluster states in nuclei. Analyzing the effects of nuclear medium on the effective polarization, some informations about nuclear structure - particularly those associated with orbital angular momentum and/or spin cluster correlations in nuclei - may be obtained. The results of recent calculations of the effective polarizations for the reactions 6Li(p vector, 2p) 5He and 14N(p vector, 2p) 13C at 320 MeV are shown and compared to previous results obtained for the single-particle [jj] shell model. (author)