Eikonal approximation in celestial CFT

A bstract We identify an eikonal regime in celestial CFT 2 which massless 2-2 scattering is dominated by t-channel exchange. derive a formula for the amplitude that resums exchanges of arbitrary integer spin to all orders coupling. The resulting phase takes same form as flat space with powers center-of-mass energy replaced weight-shifting operators on sphere. independently compute two-point function scalar propagating shockwave background and show leading order gravitational coupling suitable choice source, result agrees prediction from graviton demonstrate this can be directly obtained corresponding AdS 4 limit. finally establish general relation between amplitudes d? 1 limit d +1 Witten diagrams.