We review a series of unitarization techniques that have been used during the last decades, many of them in connection with the advent and development of current algebra and later of Chiral Perturbation Theory. Several methods are discussed like the generalized effective-range expansion, K-matrix approach, Inverse Amplitude Method, Pade approximants and the N/D method. More details are given for the latter though. We also consider how to implement them in order to correct by final-state interactions. In connection with this some other methods are also introduced like the expansion of the inverse of the form factor, the Omnes solution, generalization to coupled channels and the Khuri-Treiman formalism, among others.

中文翻译：

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强子物理中的幺正化技术与史记

我们回顾了过去几十年中使用的一系列幺正化技术，其中许多与当前代数以及后来的手性微扰理论的出现和发展有关。讨论了几种方法，如广义有效范围扩展、K 矩阵方法、逆幅度方法、Pade 近似和 N/D 方法。不过，后者提供了更多详细信息。我们还考虑如何实现它们以通过最终状态交互进行纠正。与此相关的一些其他方法也被引入，如形状因子的逆扩展、Omnes 解决方案、耦合通道的泛化和 Khuri-Treiman 形式主义等。