The S matrix of 6D super Yang-Mills and maximal supergravity from rational maps

Freddy Cachazo, Alfredo Guevara, Matthew Heydeman, Sebastian Mizera, John H. Schwarz, Congkao Wen
2018 Journal of High Energy Physics  
We present new formulas for n-particle tree-level scattering amplitudes of six-dimensional N=(1,1) super Yang-Mills (SYM) and N=(2,2) supergravity (SUGRA). They are written as integrals over the moduli space of certain rational maps localized on the (n-3)! solutions of the scattering equations. Due to the properties of spinor-helicity variables in six dimensions, the even-n and odd-n formulas are quite different and have to be treated separately. We first propose a manifestly supersymmetric
more » ... supersymmetric expression for the even-n amplitudes of N=(1,1) SYM theory and perform various consistency checks. By considering soft-gluon limits of the even-n amplitudes, we deduce the form of the rational maps and the integrand for n odd. The odd-n formulas obtained in this way have a new redundancy that is intertwined with the usual SL(2, C) invariance on the Riemann sphere. We also propose an alternative form of the formulas, analogous to the Witten-RSV formulation, and explore its relationship with the symplectic (or Lagrangian) Grassmannian. Since the amplitudes are formulated in a way that manifests double-copy properties, formulas for the six-dimensional N=(2,2) SUGRA amplitudes follow. These six-dimensional results allow us to deduce new formulas for five-dimensional SYM and SUGRA amplitudes, as well as massive amplitudes of four-dimensional N=4 SYM on the Coulomb branch.
doi:10.1007/jhep09(2018)125 fatcat:japgbllbizbutegh3spnrn4jbq