标题： 新的双标量sigma模型软定理 显示英文标题

标题： New Soft Theorems for Two-Scalar Sigma Models

摘要： 本文中，我们研究具有两个标量的sigma模型的散射振幅和软定理。我们表明，如果粒子是Goldstone玻色子，则必然得到Adler零点且不存在非平凡的软定理。对于非Goldstone玻色子，软行为通常由Cheung等人研究的几何软定理所捕获，并且右边包含低点振幅的导数。受关于2D sigma模型的近期工作的启发，我们研究了一个特殊的两个标量sigma模型，其中目标空间中的对称性转化为一种特殊但非平凡的无导数的软定理。我们进一步将这种构造推广到两类更大的此类模型中，并推导出某些软定理求和规则，同样避免了振幅的导数。我们的分析为两个标量sigma模型和软定理提供了一个有趣的层次结构，范围从Goldstone玻色子情形到一般的靶空间，展示了其间存在有趣理论。 显示英文摘要

摘要： In this paper, we study the scattering amplitudes and soft theorems for the sigma models with two scalars. We show that if the particles are Goldstone bosons, then you necessarily get Adler zero with no possibility for non-trivial soft theorems. For non-Goldstone bosons, the soft behavior is generically captured by the geometric soft theorem studied by Cheung et al., and the right-hand side contains derivatives of lower-point amplitudes. Inspired by the recent work on the 2D sigma models, we study one special two-scalar sigma model, where the presence of symmetries in the target space translates into a special but non-trivial soft theorem without derivatives. We further generalize the construction to two larger classes of such models and derive certain soft theorem sum rules, again avoiding the derivatives of amplitudes. Our analysis provides an interesting hierarchy of two-scalar sigma models and soft theorems, ranging from Goldstone boson case to a generic target space, and showing that there are interesting theories in between.