Nature of the enhancement of sub-barrier heavy-ion fusion cross section: dispersion relation approach

Sub-barrier heavy-ion fusion reactions are discussed within an effective one-channel model, which contains channel coupling effects through the presence of an inclusive energy-dependent polarization potential IPP. With the aid of an inverse dispersion relation, which gives the imaginary part of the IPP in terms of the principal part integral involving the real part, the heavy-ion systemsA1Ni +A2Ni and 16O + ASm are analysed. In particular the reactive content of the extracted imaginary part of the IPP is discussed. The first and second moments of the angular momentum distribution of the partial fusion cross section are calculated and discussed. (author)