论文标题
两体衰减的部分波形分析与螺旋形式形式主义
Partial wave analysis of two-body decay with helicity formalism
论文作者
论文摘要
在本文中，我们发现可以通过引入螺旋度方法研究的两体衰减和散射过程的角度分布。它被认为，角度分布仅取决于衰减幅度的大小，最终粒子沿$ z $轴的衰减幅度。因此，在计算角度分布时，我们只需要知道$ z $方向上的螺旋幅度即可。同时，我们还讨论了物理过程的对称性，例如奇偶校验和时间倒转转换等。在本文中研究了这些对称转换对螺旋状态和规范状态的影响。当将其应用于两个身体衰减过程时，振幅的对称性可以通过螺旋方法获得。此外，我们还引入了密度矩阵来研究最终态颗粒的极化，并讨论了密度矩阵的一些固有对称性。当我们研究最终状态颗粒的极化和角度分布时，我们可以使用这些属性来简化密度矩阵而不知道密度矩阵的所有要素。衰减和两个身体级联衰变过程可以通过螺旋方法分析，该方法具有非常好的应用。
In this paper, We find that the angular distribution of two-body decay and scattering process that can be studied by introducing the helicity method.It has been argued that the angular distribution only depends on magnitude of the decaying amplitude which final particle momentum is along the $Z$ axis. Therefore, when calculating the angular distribution,we only need to know the helicity amplitude in the $Z$ direction. At the same time, we also discuss the symmetry of physical processes, such as parity and time inversion transformation and so on. The effects of these symmetric transformations on the helicity state and the canonical states are studied in this paper. When it is applied to two body decay process, the symmetry of the amplitude can be obtained by helicity method. In addition, we also introduce the density matrix to study the polarization of the final state particles, and discuss some inherent symmetries of the density matrix. When we study the polarization and angular distribution of final state particles, we can use these properties to simplify density matrix without knowing all the elements of the density matrix.Then we find that there is a close relationship between the partial wave\cite{2003Tree}coupling constants and the angular distribution parameters, indicating that these coupling constants can be obtained by experimental fitting to data.In a word, the properties of two body decay and two body cascade decay process can be analyzed by helicity method, which has a very good application .
