2016/10/31 by Sebastian Mizera · 1 citation
Physics and Astronomy · #hep-th
paper · pdf · doi:10.1007/jhep06(2017)084
published as JHEP 1706 (2017) 084 · 25 pages, published version, Mathematica notebook attached
arxiv created 2017/06/16 · arxiv updated 2017/06/19
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/p2 are replaced by either 1/sin (πα' p2/2) or 1/tan (πα' p2/2), 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.