Role of core excitation in (d,p) transfer reactions

TL;DR

This study systematically investigates the impact of core excitation on (d,p) transfer reactions using advanced models and reaction mechanisms, revealing significant energy-dependent effects on spectroscopic factors and reaction outcomes.

Contribution

It introduces a comprehensive approach combining particle-rotor models with dynamical core excitation in reaction calculations, advancing understanding of core effects in transfer reactions.

Findings

Spectroscopic factors decrease at intermediate beam energies.

Loosely bound systems show stronger energy dependence.

Dynamical core excitation significantly alters angular distributions.

Abstract

[Background:] Recent work found that core excitation can be important in extracting structure information from (d,p) reactions. [Purpose:] Our objective is to systematically explore the role of core excitation in (d,p) reactions, and understand the origin of the dynamical effects. [Method:] Based on the particle-rotor model of $n+^{10}$Be, we generate a number of models with a range of separation energies ($S_n=0.1-5.0$ MeV), while maintaining a significant core excited component. We then apply the latest extension of the momentum-space based Faddeev method, including dynamical core excitation in the reaction mechanism to all orders, to the $^{10}$Be(d,p)$^{11}$Be like reactions, and study the excitation effects for beam energies from $E_d=15-90$ MeV. [Results:] We study the resulting angular distributions and the differences between the spectroscopic factor that would be extracted from the cross sections, when including dynamical core excitation in the reaction, to that of the original structure model. We also explore how different partial waves affect the final cross section. [Conclusions:] Our results show a strong beam energy dependence of the extracted spectroscopic factors that become smaller for intermediate beam energies. This dependence increases for loosely bound systems.