Multiparticle Factorization and the Rigidity of String Theory

Abstract

Is string theory uniquely determined by self-consistency? Causality and unitarity seemingly permit a multitude of putative deformations, at least at the level of two-to-two scattering. Motivated by this question, we initiate a systematic exploration of the constraints on scattering from higher-point factorization, which imposes extraordinarily restrictive sum rules on the residues and spectra defined by a given amplitude. These bounds handily exclude several proposed deformations of the string: the simplest "bespoke" amplitudes with tunable masses and a family of modified string integrands from "binary geometry." While the string itself passes all tests, our formalism directly extracts the three-point amplitudes for the low-lying string modes without the aid of worldsheet vertex operators.

5 pages (+ 4 pages supplementary), 2 figures

References in corpus (4)

• Causality, Analyticity and an IR Obstruction to UV Completion
• On Unitarity of Tree-Level String Amplitudes
• Bespoke Dual Resonance
• Accumulation-Point Amplitudes in String Theory

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• Lectures in Quantum Gravity
• Strings from Almost Nothing
• Higher-Spin and Higher-Point Constraints on Stringy Amplitudes
• Worldsheet for Generalized Veneziano Amplitudes
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• String Theory from Maximal Supersymmetry