Near-threshold behavior of positronium-antihydrogen scattering cross sections
Near-threshold behavior of positronium-antihydrogen scattering cross sections
复制标题
正电子素-反氢散射截面的近阈值行为
DOI：
10.1103/physreva.105.052812
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发表时间：
2022
影响因子：
2.9
通讯作者：
Froelich Piotr
中科院分区：
文献类型：
--
作者：
Yamashita Takuma;Kino Yasushi;Hiyama Emiko;Jonsell Svante;Froelich Piotr
我们对反氢原子和电子偶素原子的散射进行了全面的数值研究，碰撞能量刚好高于重排反应的阈值。碰撞的形成对于欧洲核子研究中心的实验来说非常有趣。我们处理了低于阈值的通道重排成（其中包括弹性散射，激发和去激发的正电子素和从激发态，极化和去极化，重排成，并形成Ps和在逆反应）。我们的方法是变分计算与耦合重排通道方法的结合。通过对角化完整的哈密顿量得到的薛定谔方程的四体解，与满足正确的渐近边界条件的通道函数相结合，在一个过程中，提供散射矩阵。计算所有允许的散射过程的矩阵元素的完整集合（在正向和反向方向上，而不假设详细的平衡）。散射截面是从矩阵元素计算的总角动量，正子自旋，形成所需的。用矩阵的么正性准则检验了计算的数值精度。收敛的截面检查相对于分波的贡献，在守恒的总角动量和宇称的约束下。结果表明，在阈值附近的能量行为符合维格纳定律。与形成竞争的过程的横截面。
We have performed a comprehensive numerical investigation of the scattering of antihydrogen () and positronium (Ps) atoms, at collision energies just above the threshold for the rearrangement reaction resulting inions. Formation ofincollisions is of vivid interest for experiments withat CERN. We treatallopen channels below the threshold for the rearrangement into(which includes elastic scattering, excitation and deexcitation of positronium to and from the excited states with, polarization and depolarization of, rearrangement into, and formation of Ps andin the reverse reaction). Our method is a combination of the variational calculation with the coupled rearrangement channel method. The four-body solutions of the Schrödinger equation, obtained via diagonalization of the full Hamiltonian, are combined with the channel functions that satisfy the correct asymptotic boundary conditions, in a procedure that delivers the scattering matrix. The complete set of-matrix elements for all allowed scattering processes is calculated (both in forward and reverse directions, without assumption of the detailed balance). The scattering cross sections are obtained from the-matrix elements calculated for the total angular momenta, and for the positronic spin, required for the formation of. The numerical accuracy of the calculation is checked using the criterion of unitarity of thematrix. Convergence of the cross section is examined with respect to the partial wave contributions, under the constraint of conservation of total angular momentum and parity. We show that the energy behavior of the cross sections near thresholds is consistent with the Wigner laws. The cross sections for processes that compete withformation are presented.