Two-neutron transfer reaction mechanism in ¹⁸O+²⁰⁶Pb below the Coulomb barrier: extreme cluster model calculations assuming di-neutron transfer

The pairing interaction induces nucleon-nucleon (N-N) correlation. Extensive studies have been made in the literature to understand the pairing effect. However, it is still an open question whether the pair correlation can be probed in heavy ion (HI) reactions. In a very recent work on ⁶⁰Ni+¹¹⁶Sn, the measured 2n transfer probabilities (both magnitude and slope) were reproduced, for the first time, in a microscopic calculation by incorporating the N-N pairing correlations. With a motivation to have further understanding of the role played by pairing correlations in nuclei, we have studied the 2n-transfer reaction ²⁰⁶Pb(¹⁸O,¹⁶O). As a first step to this, we have studied the relative contribution from different processes that are contributing to the absolute cross-section. The energy was chosen at below the Coulomb barrier. For HI reaction below the Coulomb barrier-though characteristic of low transfer cross-section-the two colliding nuclei interact at very large distances so that the effect of the attractive nuclear force on the Coulomb elastic waves is small and can easily be accounted for