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arXiv · 2602.12176

Single-minus gluon tree amplitudes are nonzero

Alfredo Guevara·Alexandru Lupsasca·David Skinner·Andrew Strominger·Kevin Weil
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Abstract

Single-minus tree-level $n$-gluon scattering amplitudes are reconsidered. Often presumed to vanish, they are shown here to be nonvanishing for certain "half-collinear" configurations existing in Klein space or for complexified momenta. We derive a piecewise-constant closed-form expression for the decay of a single minus-helicity gluon into $n-1$ plus-helicity gluons as a function of their momenta. This formula nontrivially satisfies multiple consistency conditions including Weinberg's soft theorem.

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Alfredo Guevara, Alexandru Lupsasca, David Skinner, Andrew Strominger, Kevin Weil. 2026-02-12. Single-minus gluon tree amplitudes are nonzero. https://arxiv.org/abs/2602.12176

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