Strong Multi-step Interference Effects in 12C(d,p) to the 9/2+ State in 13C

TL;DR

This study reveals complex multi-step interference effects in the 12C(d,p)13C reaction, emphasizing the importance of including multiple transfer pathways and their interference to accurately describe the angular distribution of the 9/2+ state.

Contribution

It demonstrates that accurate modeling of the reaction requires considering both direct and two-step transfer paths, highlighting the significant interference effects involved.

Findings

Two-step transfer via the 12C 2+ state dominates the population.

Including the 3- resonance pathway improves fit to experimental data.

Interference effects are driven by kinematic factors, not just wave function contributions.

Abstract

The population of the 9.50 MeV 9/2+ resonance in 13C by single neutron transfer reactions is expected to be dominated by the two-step route through the 12C 2+ (4.44 MeV) state, with another possible contribution via the strongly excited 3- (9.64 MeV) resonance in 12C. However, we find that a good description of the angular distribution for population of this state via the 12C(d,p)13C reaction is only possible when both direct 0+ x g_9/2 and two-step (via the 4.44 MeV 12C 2+ state) 2+ x d_5/2 paths are included in a coupled reaction channel calculation. While the calculated angular distribution is almost insensitive to the presence of the two-step path via the 9.64 MeV 12C 3- resonance, despite a much greater contribution to the wave function from the 3- x f_7/2 configuration, its inclusion is required to fit the details of the experimental angular distribution. The very large interference between the various components of the calculations, even when these are small, arises through the ``kinematic'' effect associated with the different transfer routes.