Low-energy corrections to the eikonal description of elastic scattering and breakup of one-neutron halo nuclei in nuclear-dominated reactions

Abstract

Background The eikonal approximation is a high-energy reaction model which is very computationally efficient and provides a simple interpretation of the collision. Unfortunately, it is not valid at energies around 10 MeV/nucleon, the range of energy of HIE-ISOLDE at CERN and the future ReA12 at MSU. Fukui et al. [Phys. Rev. C 90, 034617 (2014)] have shown that a simple semiclassical correction of the projectile-target deflection could improve the description of breakup of halo nuclei on heavy targets down to 20 MeV/nucleon. PurposeWe study two similar corrections, which aim at improving the projectile-target relative motion within the eikonal approximation, with the goal to extend its range of validity down to 10 MeV/nucleon in nuclear-dominated collisions, viz. on light targets. The semiclassical correction substitutes the impact parameter by the distance of closest approach of the corresponding classical trajectory. The exact continued S-matrix correction replaces the eikonal phase by the exact phase shift. Both corrections successfully describe the elastic scattering of one-neutron halo nuclei. MethodWe extend these corrections and study their efficiency in describing the breakup channel. We evaluate them in the case of 11 Be impinging on 12 C at 20 and 10 MeV/nucleon.Results Albeit efficient to reproduce the elastic channel, these corrections do not improve the description of the breakup of halo nuclei within the eikonal approximation down to 20 MeV/nucleon. ConclusionsOur analysis of these corrections shows that improving the projectile-target relative motion is not the ultimate answer to extend the eikonal approximation down to low energies. We suggest another avenue to reach this goal.

Role of continuum in nuclear direct reactions with one-neutron halo nuclei: A one-dimensional model

“…III C), the excitation energy might be a significant fraction of the available kinetic energy or even be of the same order. This resembles the limitations encountered in the eikonal model [49] (which is based on the assumption of straight projectile trajectories) when it is applied to study reactions at low beam energy [50][51][52]. Even if we used real potentials, the main conclusions on the role of the continuum in the reaction mechanism would remain unchanged.…”

Role of continuum in nuclear direct reactions with one-neutron halo nuclei: a one-dimensional model

“…In the situation shown in the last case (section 3.3), the excitation energy might be a significant fraction of the available kinetic energy or even be of the same order. This resembles the limitations encountered in the eikonal model [43] (which is based on the assumption of straight projectile trajectories) when it is applied to study reactions at low beam energy [44,45,46]. Even if we used real potentials, the main conclusions on the role of continuum in the reaction mechanism remain unchanged.…”

The eikonal model of reactions involving exotic nuclei; Roy Glauber's legacy in today's nuclear physics

“…For reactions on heavy targets, the Coulomb deflection can be easily simulated by a simple semiclassical correction, enabling a correct description of breakup reactions down to, at least, 20 MeV/nucleon [30]. On light targets however, no such correction seems to provide acceptable results to reliably analyse reactions at low energy [33].…”

“…It has been tried to apply similar corrections to nuclear-dominated reactions, hence to light targets [31,32]. Unfortunately, none of these corrections seem to work to properly describe the breakup of one-neutron halo nuclei on light targets down to 20 MeV/nucleon [33].…”