A (p, p′ γ) angular correlation study of an intermediate structure in the 3− exit channel of40Ca+p

Excitation functions of the40Ca(p,p2γ) triple angular correlations have been measured in the region of an intermediate structure centered atEp=6.25 MeV, for 12 pairs of proton and gamma detector positions. The angular correlations are consistent with the spin 5/2 assigned for these resonances and have established thep1/2 partial wave as the main decay mode of the intermediate structure in the 3− inelastic channel. These results are strongly supporting the description of the structure observed in the 3− exit channel as consisting of 2p-1h doorway states in which a 2p1/2 single-particle state weakly coupled to 3− excited core is split by residual interactions. An improved dynamical treatment, aimed to obtain the strength function of the 2p1/2 single-particle state in the 3− channel, is suggested.