Explicit inclusion of nonlocality in(d,p)transfer reactions

Abstract

Background: Traditionally, nucleon-nucleus optical potentials are made local for convenience. In recent work we studied the effects of including nonlocal interactions explicitly in the final state for (d,p) reactions, within the distorted wave Born approximation.Purpose: Our goal in this work is to develop an improved formalism for nonlocal interactions that includes deuteron breakup and to use it to study the effects of including nonlocal interactions in transfer (d,p) reactions, in both the deuteron and the proton channel.Method: We extend the finite-range adiabatic distorted wave approximation to include nonlocal nucleon optical potentials. Results: We find that nonlocality in the deuteron scattering state reduces the amplitude of the wave function in the nuclear interior, and shifts the wave function outward. In many cases, this has the effect of increasing the transfer cross section at the first peak of the angular distributions. This increase was most significant for heavy targets and for reactions at high energies.Conclusions: Our systematic study shows that, if only local optical potentials are used in the analysis of experimental (d, p) transfer cross sections, the extracted spectroscopic factors may be incorrect by up to 40% due to the local approximation.

Non local microscopic potentials for calculation of scattering observables of nucleons on deformed nuclei

“…Modern phenomenological non local potentials have been developed to study charge asymmetry dependence of the optical potential [7] and transfer reactions [3]. All these studies show that it is possible and desirable to use non local potentials when studying direct reactions.…”

“…Microscopic approches are being developped in order to improve prediction power and solve the aformentionned issue [1]. Potentials obtained microscopically are non local, and recent studies [2][3][4] have emphasized the importance of treating explicitely this nonlocality, and not through a localization procedure. These developments lead to the need of a computation code capable of solving coupled channel equations with non local potentials.…”

New developments in reaction theory: preparing for the FRIB era

“…This method was used to explore the role of core excitation in (d,p) reactions, and understand the origin of the dynamical effects [3]. Based on the particle-rotor model of n+ 10 Be, a number of 11 Belike models were generated with a range of separation energies, while maintaining a significant coreexcited component. We used the n+ 10 Be system as a toy model, included the first two states of 10 Be and coupled the additional neutron to a total spin J = 1 2 just as in 11 Be(g.s.…”

“…), but then adjusted the interaction to produce a number of models with different separation energies ranging S n = 0.1 − 5.0 MeV. We then applied the method of [7], which includes dynamical core excitation in the reaction mechanism to all orders, to the 10 Be(d,p) 11 Be like reactions, and studied the excitation effects for beam energies from the range E d = 15 − 90 MeV [3]. We compared the resulting angular distributions and the spectroscopic factor that would be extracted from the cross sections, when including dynamical core excitation in the reaction model (S f add ), to that of the original structure model S th .…”

“…Based on the particle-rotor model of n+ 10 Be, a number of 11 Belike models were generated with a range of separation energies, while maintaining a significant coreexcited component. We used the n+ 10 Be system as a toy model, included the first two states of 10 Be and coupled the additional neutron to a total spin J = 1 2 just as in 11 Be(g.s. ), but then adjusted the interaction to produce a number of models with different separation energies ranging S n = 0.1 − 5.0 MeV.…”