Sub- and near-barrier fusion reactions experimental results

Dipartimento di Fisica e Astronomia, Università di Padova, Padova, Italy and INFN, Sezione di Padova, Padova, Italy

Published online: 11 May 2016

Abstract

Early data of sub-barrier fusion teached us that cross sections may strongly depend on the structure of colliding nuclei and on couplings to transfer channels. The influence of transfer is clearly indicated in the excitation functions of different nickel isotopes and various Ca+Zr systems. Fusion barrier distributions often yield the fingerprint of the relevant inelastic and transfer couplings. At lower energies, far below the barrier the slope of the excitation function keeps increasing in many cases, so that the cross sections are strongly over-predicted by standard coupled-channels (CC) calculations; this was named a hindrance effect.

Furthermore, light heavy-ion systems show cross section oscillations above the Coulomb barrier. Recent experiments have been performed on the fusion of ^28,30Si+^28,30Si systems where all phenomena cited above show up. In particular regular oscillations that have been revealed above the barrier for ²⁸Si+²⁸Si and have been interpreted as the consequence of the strong channel couplings and/or the oblate deformation of ²⁸Si.