Symmetries and analytic properties of scattering amplitudes in image SYM theory Original Research Article

In addition to the superconformal symmetry of the underlying Lagrangian, the scattering amplitudes in planar image super-Yang–Mills theory exhibit a new, dual superconformal symmetry. We address the question of how powerful these symmetries are to completely determine the scattering amplitudes. We use the example of the NMHV superamplitudes to show that the combined action of conventional and dual superconformal symmetries is not sufficient to fix all the freedom in the tree-level amplitudes. We argue that the additional information needed comes from the study of the analytic properties of the amplitudes. The requirement of absence of spurious singularities, together with the correct multi-particle singular behavior, determines the unique linear combination of superinvariants corresponding to the n-particle NMHV superamplitude. The same result can be obtained recursively, by relating the n- and image-particle amplitudes in the singular collinear limit. We also formulate constraints on the loop corrections to the superamplitudes, following from the analytic behavior in the above limits.