B. Eden, HU Berlin

Title: “Colour-dressed hexagon tessellations and the torus part of the norm”

The talk will summarise arXiv:1710.10212 with Yunfeng Jiang, Dennis le Plat and Alessandro Sfondrini.

Abstract:

We continue the study of four-point correlation functions by the hexagon
tessellation approach initiated in arXiv:1611.05436, 1611.05577 [hep-th].

We consider planar tree-level correlation functions in N = 4 supersymmetric
Yang-Mills theory involving two non-protected operators.
We find that, in order to reproduce the field theory result, it is necessary to
include SU(N) colour factors in the hexagon formalism; moreover, we find that the
hexagon approach as it stands is naturally tailored to the single-trace part of
correlation functions, and does not account for multi-trace admixtures. We discuss
how to compute correlators involving double-trace operators, as well as more general
1/N effects; in particular we compute the whole next-to-leading order in the large-N
expansion of tree-level BMN two-point functions by tessellating a torus with
punctures.

Finally, we turn to the issue of “wrapping”, Luescher-like corrections. We show
that SU(N) colour-dressing reproduces an earlier empirical rule for incorporating
single-magnon wrapping, and we provide a direct interpretation of such wrapping
processes in terms of N=2 supersymmetric Feynman diagrams.