  The simplicity of maximally supersymmetric Yang-Mills theory makes it an
ideal theoretical laboratory for developing computational tools, which
eventually find their way to QCD applications. In this contribution, we
continue the investigation of a recent proposal by Basso, Sever and Vieira, for
the nonperturbative description of its planar scattering amplitudes, as an
expansion around collinear kinematics. The method of arXiv:1310.5735, for
computing the integrals the latter proposal predicts for the leading term in
the expansion of the 6-point remainder function, is extended to one of the
subleading terms. In particular, we focus on the contribution of the 2-gluon
bound state in the dual flux tube picture, proving its general form at any
order in the coupling, and providing explicit expressions up to 6 loops. These
are included in the ancillary file accompanying the version of this article on
the arXiv.
