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arXiv · 1611.07479

Leading order multi-soft behaviors of tree amplitudes in NLSM

Yi-Jian Du·Hui Luo
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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.

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Yi-Jian Du, Hui Luo. 2017-01-15. Leading order multi-soft behaviors of tree amplitudes in NLSM. https://doi.org/10.1007/jhep03(2017)062

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