标题： 中微子的电荷半径 显示英文标题

标题： On the charge radius of the neutrino

摘要： 使用夹点技术，在一环阶次下我们构建了一个中微子电荷半径，该半径是有限的，既不依赖于规范固定参数，也不依赖于所采用的规范固定方案，并且与过程无关。 此定义仅来自于一个有效的光子-中微子一环顶点，而没有参考框图或自能贡献。 在这一构造中，$WW$框图的作用被仔细考察。 特别是，证明了从中微子电荷半径的定义中排除有效WW框图并不是一种约定，而是在目标费米子为右旋极化时实际上动态实现的。 通过这种方式，我们得到了有效的自能、顶点和框图的独特分解，它们各自都尊重电弱规范不变性。 我们详细阐述了该机制在树图层次的起源，该机制在单环阶次下强制对费曼图中出现的纵向动量进行大质量抵消，并特别涉及与理论的非阿贝尔性质相关的动量。 进一步澄清了已知的夹点技术与背景场方法之间的联系相关的问题。 报告了中微子电荷半径的显式闭合表达式。 显示英文摘要

摘要： Using the pinch technique we construct at one-loop order a neutrino charge radius, which is finite, depends neither on the gauge-fixing parameter nor on the gauge-fixing scheme employed, and is process-independent. This definition stems solely from an effective proper photon-neutrino one-loop vertex, with no reference to box or self-energy contributions. The role of the $WW$ box in this construction is critically examined. In particular it is shown that the exclusion of the effective WW box from the definition of the neutrino charge radius is not a matter of convention but is in fact dynamically realized when the target-fermions are right-handedly polarized. In this way we obtain a unique decomposition of effective self-energies, vertices, and boxes, which separately respect electroweak gauge invariance. We elaborate on the tree-level origin of the mechanism which enforces at one-loop level massive cancellations among the longitudinal momenta appearing in the Feynman diagrams, and in particular those associated with the non-abelian character of the theory. Various issues related to the known connection between the pinch technique and the Background Field Method are further clarified. Explicit closed expressions for the neutrino charge radius are reported.