Recent Advances in Nuclear Reaction Theories for Weakly Bound Nuclei: Reexamining the Problem of Inclusive Breakup

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In this paper, we address the problem of the post-prior equivalence in the calculation of inclusive breakup and transfer cross sections. For that, we employ the model proposed by Ichimura, Austern, and Vincent [Phys. Rev. C 32, 431 (1985)], conveniently generalized to include the part of the cross section corresponding the transfer to bound states. We pay particular attention to the case in which the unobserved particle is left in a bound state of the residual nucleus, in which case the theory prescribes the use of a complex potential, responsible for the spreading width of the populated single-particle states. We see that the introduction of this complex potential gives rise to an additional term in the prior cross section formula, not present in the usual case of real binding potentials. The equivalence is numerically tested for reaction induced by deuterons. * jinl@ohio.edu † moro@us.es

Section: Theoretical Frameworkmentioning

confidence: 77%

Post-prior equivalence for transfer reactions with complex potentials

Lei

Moro

2018

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“…Due to the computational limitations at that time, this model was apparently fallen into disuse. Recently , the model model has been re-examined by several groups [7][8][9][10][11][12]. Moreover a systematic study of the alpha productions in 6 Li induced reactions has been recently reported by Lei and Moro [13], in which the numerical calculations using the IAV model agree well with the experimental data.…”

Section: Introductionmentioning

confidence: 89%

Inclusive breakup calculations in angular momentum basis: Application to Li7+Ni58

Lei¹

2018

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The angular momentum basis method is introduced to solve the inclusive breakup within the model proposed by Ichimura, Austern, and Vincent [Phys. Rev. C 32, 431 (1985)]. This method is based on the geometric transformation between Jacobi coordinates, thus it is easy to corporate with particle spins. To test the validity of this partial wave expansion method, a benchmark calculation is done comparing with the one given in [Phys. Rev. C 92, 044616 (2015)]. Using the distortedwave Born approximation (DWBA) version of IAV model, some applications to 7 Li reactions are presented and compared with available data.

“…For the non-elastic breakup calculations, we rely also on a α + d model, but the spin of the deuteron is ignored, since our current implementation of the IAV model ignores the intrinsic spin of the fragments. This approximation was also used in our previous works [2][3][4].…”

Section: Comparison With Experimental Datamentioning

confidence: 99%

“…This approximation was also used in our previous works [2][3][4]. 6 Li + 208 Pb at the incident energies indicated by the labels.…”

Section: Comparison With Experimental Datamentioning

confidence: 99%

“…When one is only interested in the evaluation of the singles' cross section (for example, the energy or angular distribution of α particles), rather than on the separate contributing mechanisms, one may resort to the inclusive breakup models proposed in the 1980s and recently reexamined by several groups [2][3][4][5][6]. In these models, the sum over all the possible final states through which the unobserved fragment d may interact with the target is done in a formal way, making use of the Feshbach projection formalism [7] and closure.…”

Section: Introductionmentioning

confidence: 99%

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Comprehensive analysis of large α yields observed in Li6 -induced reactions

Lei

Moro

2017

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Background: Large α yields have been reported over the years in reactions with 6 Li and 7 Li projectiles. Previous theoretical analyses have shown that the elastic breakup (EBU) mechanism (i.e., projectile breakup leaving the target in its ground state) is able to account only for a small fraction of the total α-inclusive breakup cross sections, pointing toward the dominance of nonelastic breakup (NEB) mechanisms. Purpose: We aim to provide a systematic study of the α-inclusive cross sections observed in nuclear reactions induced by 6 Li projectiles. In addition to estimating the total α singles' cross sections, it is our goal to evaluate angular and energy distributions of these α particles and compare them with experimental data, when available. Method: We compute separately the EBU and NEB components of the inclusive breakup cross sections. For the former, we use the continuum-discretized coupled-channels (CDCC) method, which treats this mechanism to all orders. For the NEB part, we employ the model proposed by Ichimura et al. [Phys. Rev. C 32, 431 (1985)], within the distorted-wave Born approximation (DWBA). Results: Overall, the sum of the computed EBU and NEB cross sections is found to reproduce very well the measured singles' cross sections. In all cases analyzed, we find that the inclusive breakup cross section is largely dominated by the NEB component. Conclusions:The presented method provides a global and systematic description of inclusive breakup reactions induced by 6 Li projectiles. It provides also a natural explanation of the previously observed underestimation of the measured α yields by CDCC calculations. The method used here can be extended to other weakly bound projectiles, including halo nuclei.