SWANLOP: Scattering waves off nonlocal optical potentials in the presence of Coulomb interactions

We introduce the package SWANLOP to calculate scattering waves and corresponding observables for nucleon elastic collisions off spin-zero nuclei. The code is capable of handling local and nonlocal optical potentials superposed to long-range Coulomb interaction. Solutions to the implied Schrödinger integro-differential equation are obtained by solving an integral equation of Lippmann–Schwinger type for the scattering wavefunctions, ψ = ϕ_C + G_C U_S ψ, providing and exact treatment to the Coulomb force Arellano and Blanchon (2019). The package has been developed to handle potentials either in momentum or coordinate representations, providing flexible options under each of them. The code is fully self-contained, being dimensioned to handle any A >= 4 target for nucleon beam energies of up to 1.1 GeV. Accuracy and benchmark applications are presented and discussed.

本研究引入SWANLOP软件包，用于计算核子与自旋为零的原子核发生弹性碰撞时的散射波及其对应可观测量。该程序可处理叠加了长程库仑相互作用的局域与非局域光学势。针对所涉及的薛定谔积分微分方程，我们通过求解适用于散射波函数ψ = ϕ_C + G_C U_S ψ的李普曼-施温格（Lippmann–Schwinger）型积分方程，实现了对库仑力的严格处理（Arellano与Blanchon，2019）。本软件包支持动量空间与坐标空间下的势场表示，并为两种表示均提供了灵活的操作选项。该程序完全自包含，可处理核子束流能量最高达1.1 GeV时质量数A≥4的所有靶核。文中还展示并讨论了该程序的精度验证与基准测试应用案例。