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arXiv · 2412.13368

Bootstrapping Extremal Scalar Amplitudes With and Without Supersymmetry

Justin Berman·Henriette Elvang·Nicholas Geiser·Loki L. Lin
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Abstract

We re-examine positivity bounds on the $2\to2$ scattering of identical massless real scalars with a novel perspective on how these bounds can be used to constrain the spectrum of UV theories. We propose that the entire space of consistent weakly-coupled (and generically non-supersymmetric) UV amplitudes is determined as a convex hull of the massive scalar amplitude and a one-parameter family of scalarless "extremal amplitudes" parameterized by the ratio of the masses of the two lightest massive states. Further, we propose that the extremal amplitudes can be constructed from a similar one-parameter set of maximally supersymmetric amplitudes, leading to the surprising possibility that the S-matrix bootstrap with maximal supersymmetry may be sufficient to determine the entire allowed space of four-point amplitudes! Finally, we show that minimal spectrum input reduces the allowed space of Wilson coefficients to small islands around the open string Dirac-Born-Infeld tree amplitude and the closed string Virasoro-Shapiro amplitude.

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Justin Berman, Henriette Elvang, Nicholas Geiser, Loki L. Lin. 2024-12-17. Bootstrapping Extremal Scalar Amplitudes With and Without Supersymmetry. https://arxiv.org/abs/2412.13368

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