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arXiv · 2302.04895

Bootstrapping the String KLT Kernel

Alan Shih-Kuan Chen·Henriette Elvang·Aidan Herderschee
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Abstract

We show that a generalized version of the 4-point string theory KLT double-copy map is the most general solution to the minimal-rank double-copy bootstrap in effective field theory. This follows from significant restrictions of the 4-point map resulting from the 6-point bootstrap analysis. The generalized 4-point double-copy map is defined by a function with only two parameters times a simple function that is symmetric in $s,t,u$. The two parameters can be interpreted as independent choices of $\alpha'$, one for each of the two sets of amplitudes double-copied with the map. Specifically, each of those two sets of amplitudes must obey either the string monodromy relations or the field theory KK & BCJ relations; there are no other options. We propose a closed form of the new double-copy map that interpolates between the original KLT string double-copy and the open & closed string period integrals. The construction clarifies the "single-valued projection" property of the Riemann zeta-function values for the 4-point string theory double copy.

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Alan Shih-Kuan Chen, Henriette Elvang, Aidan Herderschee. 2023-02-09. Bootstrapping the String KLT Kernel. https://arxiv.org/abs/2302.04895

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