AI 中文总结
本文采用Raubold-Lynch序贯两体衰变算法，构造超氚核三体介子衰变相空间，生成带电、中性π介子衰变道的未加权事件，为衰变率计算及中性π介子道预测提供运动学基准。
AI 中文摘要
本文提出了一种针对超氚核三体介子衰变相空间的蒙特卡罗构造方法，该方法采用Raubold-Lynch序贯两体衰变算法实现。该方法将三体衰变分解为通过虚中间子系统的连续两体衰变，其中间子系统的不变质量在全部运动学允许区域内采样；构造过程采用精确的相对论两体运动学与洛伦兹变换，以获取所有衰变产物的完整四动量。该构造方法应用于带电π介子与中性π介子衰变道，所生成的事件可复现洛伦兹不变的三体相空间测度；其得到的动量谱、两两动量关联、张开角分布及Dalitz图，为两种衰变模式提供了完整的运动学表征。中性π介子道具有更大的可用三体能量，对应更宽的运动学极限；所生成的未加权事件提供了运动学基准，后续可逐事件用弱衰变矩阵元加权，以计算衰变率及其他可观测物理量。对于目前无实验数据的中性π介子道，洛伦兹不变相空间构成了预测的有用基准。
英文摘要
A Monte Carlo construction is presented for the three-body mesonic decay phase space of the hypertriton. This is accomplished using the Raubold-Lynch sequential two-body decay algorithm. The method factorises this three-body decay into successive two-body decays through a virtual intermediate subsystem, whose invariant mass is sampled over the full kinematically allowed region. Exact relativistic two-body kinematics and Lorentz transformations are employed to construct complete four-momenta for all decay products. The construction is applied to both charged- and neutral-pion decay channels, yielding events that reproduce the Lorentz-invariant three-body phase-space measure. The resulting momentum spectra, pairwise momentum correlations, opening-angle distributions, and Dalitz plots furnish a complete kinematic characterisation of both decay modes. The neutral-pion channel exhibits a larger available three-body energy and correspondingly broader kinematic limits. The unweighted events generated provide a kinematic baseline that can subsequently be weighted event by event with a weak-decay matrix element, for computing decay rates and other observables. For the neutral-pion channel, where no experimental data currently exists, the Lorentz-invariant phase-space constitutes a useful baseline for predictions.
Comments25 pages, 26 figures
