Leading order multi-soft behaviors of tree amplitudes in NLSM

Abstract

In this paper, we investigate multi-soft behaviors of tree amplitudes in nonlinear sigma model (NLSM). The leading behaviors of amplitudes with odd number of all-adjacent soft pions are zero. We further propose and prove that leading soft factors of amplitudes with even number all-adjacent soft pions can be expressed in terms of products of the leading order Berends-Giele sub-currents in Cayley parametrization. Each sub-current in the expression contains at most one hard pion. Discussions are generalized to amplitudes containing arbitrary number of nonadjacent soft blocks: The leading behaviors of amplitudes where at least one soft block has odd number of adjacent soft pions are zero; The leading soft factors for amplitudes where all soft blocks containing even number of soft pions are given by products of soft factors for these blocks.

27pages, 7 figures; references added and typos modified

References in corpus (5)

• Abelian Z-theory: NLSM amplitudes and alpha'-corrections from the open string
• Extensions of Theories from Soft Limits
• Scattering Equations, Twistor-string Formulas and Double-soft Limits in Four Dimensions
• Recursion Relations for Tree-level Amplitudes in the SU(N) Non-linear Sigma Model
• Origin of Soft Limits from Nonlinear Supersymmetry in Volkov-Akulov Theory

Cited by in corpus (5)

• Semi-abelian Z-theory: NLSM+phi^3 from the open string
• The Infrared Structure of Nambu-Goldstone Bosons
• The Infrared Structure of Exceptional Scalar Theories
• Higher-order tree-level amplitudes in the nonlinear sigma model
• Exploring the Landscape for Soft Theorems of Nonlinear Sigma Models