𝒩 = 4 single-minus superamplitudes and dual superconformal symmetry

Abstract

We construct the 𝒩 = 4 supersymmetric completion of the recently proposed single-minus gluon amplitudes in (2, 2) signature, which are nonvanishing for all multiplicities on a half-collinear kinematic locus. The superamplitude factorises into a permutation-invariant measure ∆⁽ⁿ⁻¹⁾ with uniform little-group weight that imposes the half-collinearity constraint, a piecewise constant stripped amplitude \({\widetilde{A}}_{1\dots n}\) that is helicity blind and dual conformal invariant, and (super)momentum conservation delta functions. For n = 3, our superamplitude reduces to the known \(\overline{\text{M}\text{H}\text{V} }\) superamplitude. We prove dual superconformal covariance of the n-point superamplitude, and further analyse the Gr(k, n) Grassmannian integral at k = 1. Finally, we present the corresponding single-minus superamplitude in 𝒩 = 8 supergravity.