Ellis Ye Yuan

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] In a common convention,with conserved massless momenta $k_a$ and puncture coordinates ${\sigma }_a$. The equations provide algebraic structure for scattering calculations rather than trajectories of particles moving on that auxiliary sphere.