Strings on Celestial Sphere

Understand

We transform superstring scattering amplitudes into the correlation functions of primary conformal fields on two-dimensional celestial sphere.

• The points on celestial sphere are associated to the asymptotic directions of (light-like) momenta of external particles, with the Lorentz group realized as the SL(2,C) conformal symmetry of the sphere.
• The energies are dualized through Mellin transforms into the parameters that determine dimensions of the primaries.
• We focus on four-point amplitudes involving gauge bosons and gravitons in type I open superstring theory and in closed heterotic superstring theory at the tree-level.