One-neutron transfer from O16 to Al27 and Si28 targets at Elab=240MeV

Background: Transfer reactions induced by heavy ions have been explored to study the role of pairing in the two-nucleon transfers. However, many reaction channels are often open and couplings between them must be considered. Some of these couplings are effectively taken by suitable optical potentials whereas other channels are explicitly considered into the coupling scheme. The interplay between optical potentials and coupling schemes may lead to ambiguities in the interpretation of transfer mechanisms.Purpose: Relevant parameters in the calculations can be constrained by several reactions measured under the same experimental conditions. This may lead to a unified theoretical reaction scheme that can be applied to properly judge the role of sequential and simultaneous processes in the two-nucleon transfers.Methods: In this work we analyze the one-neutron transfer reactions to 27Al and 28Si induced by (16O, 15O) at Elab = 240 MeV. The choice of targets is of particular interest: within the weak coupling model, the 27Al can be interpreted as a proton hole coupled to the 28Si core. The parameters of the optical potentials to describe the elastic and inelastic scattering in these reactions have been studied in a previous publication. Here, we focus on the reaction and nuclear structure models to describe the experimental cross sections. We performed coupled channel Born approximation (CCBA) and coupled reaction channels (CRC) using spectroscopic amplitudes obtained from shell model with three different interactions and single-particle model spaces.Results: The optical potentials and coupling schemes provide a good description of the angular distributions of the cross sections, in which the CRC calculations give a slightly better agreement with experimental than the CCBA one. We compare CRC calculations using spectroscopic amplitudes from three different shell-model interactions. They all give a reasonable description of the experimental data except for the transfer that populates the 7/2-1 state in 29Si. This requires a 1 f7/2 single-particle state, present only in the model space for one of the considered interactions. Conclusions: Within the same theoretical methodology, we are able to achieve an overall good description of the experimental data for one-neutron transfer in the 27Al(16O, 15O) 28Al and 28Si(16O, 15O) 29Si at 240 MeV. This methodology will be adopted to study the proton transfer channels in these systems in a future work.