Discretization methods of the breakup continuum in deuteron-nucleus collisions.
Discretization methods of the breakup continuum in deuteron-nucleus collisions.
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氘核碰撞中破裂连续体的离散化方法。
DOI：
10.1103/physrevc.39.1709
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Rawitscher
中科院分区：
文献类型：
--
作者：
Rasoanaivo;Rawitscher
比较了S波n-p分裂连续体的两种离散化方法，并用数值方法研究了这两种离散化方法对弹性氘核散射矩阵元的影响。在其中一种方法中，n-p哈密顿量的连续本征态在大小为k的离散动量柱上求平均。在另一种方法中，连续谱被展开成一组可归一化的基函数，物理上相当于将n-p势放入盒子中。结果表明，对于入射能量分别为21.6 MeV和45 MeV的{Ni}(d，d)粒子，这两种离散化技术具有相同的物理特性和结果。然而，入射氘的能量越低，动量离散化的答案收敛到最终结果的能力就越差。对角化方法在这方面表现得更好。数值证明了分裂空间势的长尾不敏感地影响弹性S矩阵元的理论期望。这一结果从数学上解释了为什么破碎连续体的离散化是包含破碎效应的一种可行和实用的方法。
Two methods of discretization of the s-wave n-p breakup continuum are compared, and their effect on the elastic deuteron-nucleus scattering matrix elements is numerically investigated. In one of the methods, the continuum eigenstates of the n-p Hamiltonian are averaged over discretized momentum bins of size \ensuremath{\Delta}k. In the other, which is a form of the ${L}^{2}$ diagonalization method, the continuum is expanded in a set of normalizable basis functions, which physically correspond to placing the n-p potential into a box. It is found, in the case of $^{58}\mathrm{Ni}$(d,d) at incident deuteron energies ${E}_{d}$=21.6 and 45 MeV, that those two discretization techniques consistently display the same physics and yield the same results. However, the lower the incident deuteron energy, the less well do the momentum discretized answers converge to a final result. The diagonalization method is found to perform better in this respect. The theoretical expectation that the long range tails of the potentials in breakup space do not sensitively affect the elastic S-matrix elements is demonstrated numerically. This result provides the mathematical reason why the discretization of the breakup continuum is a viable and practical procedure of including the breakup effects.