Ellis Ye Yuan co-developed the scattering equations with Freddy Cachazo and Song He, connecting massless-particle kinematics with marked points on a sphere.[ref]
Scattering Equations and KLT Orthogonality by Freddy Cachazo and others. Definition and solution algorithm
In a common convention,with conserved massless momenta and puncture coordinates . The equations provide algebraic structure for scattering calculations rather than trajectories of particles moving on that auxiliary sphere. New to topics? Read the docs here!