Cluster adjacency beyond MHV

Understand

We explore further the notion of cluster adjacency, focussing on non-MHV amplitudes.

• We extend the notion of adjacency to the BCFW decomposition of tree-level amplitudes.
• Adjacency controls the appearance of poles, both physical and spurious, in individual BCFW terms.
• We then discuss how this notion of adjacency is connected to the adjacency already observed at the level of symbols of scattering amplitudes which controls the appearance of branch cut singularities.