# Influence of target deformation and deuteron breakup in (d,p) transfer reactions

## TL;DR

This paper investigates how target deformation and deuteron breakup influence (d,p) transfer reactions using coupled-channels methods, providing a computationally efficient alternative to Faddeev calculations and clarifying the physical origins of observed effects.

## Contribution

It introduces an extended CDCC-BA approach to study target excitations in (d,p) reactions, comparing results with other coupled-channels methods and Faddeev calculations.

## Key findings

- Both formalisms reproduce deformation effects seen in Faddeev calculations.
- Deformation effects originate from interference between direct and two-step transfer processes.
- The coupled-channels approach offers a less demanding alternative to Faddeev calculations.

## Abstract

The effect of core excitations in transfer reactions of the form A(d, p)B has been found to affect significantly the calculated cross sections and to depend strongly and non-linearly on the incident deuteron energy in Faddeev/AGS calculations. Our goal is to investigate these effects within a coupled-channels formulation of the scattering problem which, in addition of being computationally less demanding than the Faddeev counterpart, may help shed some light into the physical interpretation of the cited effects. We use an extended version of the continuum-discretized coupled-channels (CDCC) method with explicit inclusion of target excitations within a coupled-channels Born approximation (CDCC-BA) formulation of the transfer transition amplitude. We compare the calculated transfer cross sections with those obtained with an analogous calculation omitting the effect of target excitation. We consider also an adiabatic coupled channels (ACC) method. Our working example is the 10 Be(d,p) 11 Be reaction. We find that both formalisms are able to reproduce the effects of deformation found in Faddeev calculations, whose origin stems from the interference of the direct one-step transfer, and the two-step transfer following target excitation.