Scattering amplitudes at strong coupling for 4K gluons

TL;DR

This paper investigates strong coupling scattering amplitudes for 4K gluons, addressing degeneracies and monodromy issues, and extends methods to compute T functions from Y functions, confirming results for eight-point cases.

Contribution

It introduces a method to compute T functions from Y functions for 4K gluons at strong coupling, resolving degeneracy and monodromy challenges.

Findings

Derived T functions from Y functions for 4K gluons.

Resolved degeneracy issues in the n=4K case.

Confirmed eight-point amplitude results in AdS_3.

Abstract

In this paper we study the scattering amplitudes at strong coupling for the case where the number of gluons is a multiple of four. This is an important missing piece in arXiv:1002.2459. The tricky point for n=4K is that there is some accidental degeneracy in such case. We explain this point in detail and show that a non-trivial monodromy around infinity was developed by the world-sheet coordinate transformation appearing in the computation. It turns out that besides solving the Y system, we also need to calculate T functions to compute the full amplitudes. We show that the T functions can be derived by taking a limit of Y functions of a higher-point case. As a check, we obtain the known result of eight-point in AdS_3 case.