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Xin-Le Shang

Publications and source records attributed to Xin-Le Shang.

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Microscopic Optical Potential from Brueckner-Hartree-Fock Theory

Modern Brueckner-Hartree-Fock (BHF) calculations are very successful in describing various properties of symmetric and asymmetric nuclear matter. Within BHF theory a microscopic optical potential (MOP) for nucleon-nucleus scattering is developed. First, we parametrize the energy and density dependence of complex optical potentials in nuclear matter based on BHF calculations and then we construct the MOP for finite nuclei with the local density approximation extended to include the finite-range effects. The density distribution and the spin-orbit contribution are calculated from the Hartree-Fock (HF) approximation with LNS5 Skyrme interaction, the latter being constrained by the BHF results. The central real and imaginary potentials turn out to be quantitatively consistent with the phenomenological global Koning-Delaroche (KD) potentials. The performance of MOP is evaluated by considering neutron/proton scattering on $^{40,48}$Ca. The elastic scattering differential cross sections, analyzing powers and total/reaction cross sections are analyzed in the energy below 200 MeV. A good agreement between the theoretical results and the measurements is achieved. Since our results are presented in the analytic forms, they can thus be used easily in the analysis of the experimental data of the nucleon scattering on exotic nuclei.

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Coexistence of isospin I = 0 and I = 1 pairings in asymmetric nuclear matter

The coexistence of neutron-neutron (n-n), proton-proton (p-p), and neutron-proton (n-p) pairings is investigated by adopting an effective density-dependent contact pairing potential. These three types of pairings can coexist only if the n-p pairing is stronger than the n-n and p-p pairings for isospin asymmetric nuclear matter. In addition, the existence of n-n and p-p pairs might enhance n-p pairings in asymmetric nuclear matter when the n-p pairing strength is significantly stronger than the n-n and p-p ones. Conversely, the n-p pairing is reduced by the n-n and p-p pairs when the n-p pairing interaction approaches n-n and p-p pairings.

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Exact solution of the Brueckner-Bethe-Goldstone equation with three-body forces in nuclear matter

An exact treatment of the operators Q/e(ω) and the total momentum is adopted to solve the nuclear matter Bruecker-Bethe-Goldstone equation with two- and three-body forces. The single-particle potential, equation of state and nucleon effective mass are calculated from the exact G-matrix. The results are compared with those obtained under the angle-average approximation and the angle-average approximation with total momentum approximation. It is found that the angle-average procedure, whereas preventing huge calculations of coupled channels, nevertheless provides a fairly accurate approximation. On the contrary, the total momentum approximation turns out to be quite inaccurate compared to its exact counterpart.

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