STRONG ENHANCEMENT OF 2-PROTON TRANSFER IN THE CA-40(CL-37,K-39)AR-38REACTION

Measurements of one-and two-proton transfer in the system Cl-37+ Ca-40 at energies close to the Coulomb barrier have been performed. The two -proton transfer to ground states attains cross sections which are com parable to the one-proton transfer. The strong enhancement of the prot on-pair transfer is interpreted in terms of a combined action of stati c and dynamic proton-proton correlations, for example in the 2(+) stat e of Ar-38 and in the 0(+) ground state of Ca-40 which are introduced by mixing of shell model configurations across two major shells with < (h)overbar>omega = 2 and 3 of different parities (s(1/2), d(3/2) and f (7/2), P-3/2). This effect, which is called hybridization, induces a s trong spatial polarization of the nucleons in the two-proton wave-func tion and enhances the two-proton transfer cross section. Coupled react ion channel calculations reproduce consistently the one and two proton transfer using spectroscopic information from light ion reactions.