We propose a new splitting behavior of tree-level string/particle amplitudes for massless scalars, gluons and gravitons. We identify certain subspaces in the space of Mandelstam variables, where the universal Koba-Nielsen factor splits into two parts (each with an off-shell leg). Both open- and closed-string amplitudes with Parke-Taylor factors naturally factorize into two stringy currents, which implies the splitting of bi-adjoint ϕ3 amplitudes and via a simple deformation to unified stringy amplitudes, the splitting of amplitudes in the non-linear sigma model and Yang-Mills-scalar theory; the same splitting holds for scalar amplitudes without color such as the special Galileon. Remarkably, if we impose similar constraints on Lorentz products involving polarizations, gluon and graviton amplitudes in bosonic string and superstring theories also split into two (stringy) currents. A special case of the splitting implies soft theorems, and more generally it extends recently proposed smooth splittings and new factorizations near zeros to all these theories.

中文翻译：

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树级弦和粒子散射振幅的通用分裂


我们提出了一种新的树级弦/粒子振幅的分裂行为，用于无质量标量、胶子和引力子。我们在 Mandelstam 变量的空间中确定了某些子空间，其中通用 Koba-Nielsen 因子分为两部分（每部分都有一条离壳边）。具有 Parke-Taylor 因子的开弦和闭弦振幅自然地分解成两个细流，这意味着双伴随 φ3 振幅的分裂，并通过简单的变形获得统一的细长振幅，非线性 sigma 模型和 Yang-Mills 标量理论中的振幅分裂;同样的分裂适用于没有颜色的标量振幅，例如特殊的 Galileon。值得注意的是，如果我们对涉及极化的洛伦兹积施加类似的约束，那么玻色子弦和超弦理论中的胶子和引力子振幅也会分裂成两个（细状）电流。分裂的一个特例意味着软定理，更一般地说，它将最近提出的平滑分裂和接近零的新因式分解扩展到所有这些理论。