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arXiv · 1610.04230

Inverse of the String Theory KLT Kernel

Sebastian Mizera
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Abstract

The field theory Kawai-Lewellen-Tye (KLT) kernel, which relates scattering amplitudes of gravitons and gluons, turns out to be the inverse of a matrix whose components are bi-adjoint scalar partial amplitudes. In this note we propose an analogous construction for the string theory KLT kernel. We present simple diagrammatic rules for the computation of the $α'$-corrected bi-adjoint scalar amplitudes that are exact in $α'$. We find compact expressions in terms of graphs, where the standard Feynman propagators $1/p^2$ are replaced by either $1/\sin (πα' p^2/2)$ or $1/\tan (πα' p^2/2)$, as determined by a recursive procedure. We demonstrate how the same object can be used to conveniently expand open string partial amplitudes in a BCJ basis.

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Sebastian Mizera. 2017-06-16. Inverse of the String Theory KLT Kernel. https://doi.org/10.1007/jhep06(2017)084

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