标题： piNN系统在三维和四维中的少体描述 显示英文标题

标题： Few-Body Descriptions of the piNN System in Three and Four Dimensions

摘要： 我们总结了piNN系统少体描述的最新理论进展。 先前的描述，无论是三维还是四维的，都被证明存在严重的理论不一致之处。 我们说明了三维方法如何受到重整化问题的影响，以及四维描述如何同时存在图的过度计数和不足计数。 然后我们展示了这些理论问题是如何最近被克服的，从而得到了piNN系统的新的实用少体方程。 显示英文摘要

摘要： We summarise the recent theoretical progress in few-body descriptions of the piNN system. Previous descriptions, both three- and four-dimensional, are shown to possess serious theoretical inconsistencies. We illustrate how three-dimensional approaches suffer from renormalisation problems, and how four-dimensional descriptions contain both overcounting and undercounting of diagrams. We then show how such theoretical problems have been recently overcome, leading to new practical few-body equations for the piNN system.