We revisit a remarkable relation discovered by Lipatov in 1982 of the 2 -> N multi-particle Regge amplitude in Einstein gravity to its counterpart in QCD. We demonstrate [1] that Lipatov's result for the effective graviton emission vertex (originally obtained via Feynman diagrams and analytic properties of scattering amplitudes) can be recovered by computing gravitational radiation produced in the collision of two gravitational shockwaves. This analysis mirrors analogous prior computations of gluon production in heavy ion collisions modeled by colliding gluon shockwaves. In an upcoming work [2], we show that a precise double copy relation employing color-kinematic duality exists between the effective emission vertices in QCD and gravity. These relations strongly suggest that strong field techniques developed for the former could, with appropriate modifications, be applied to compute the spectrum of gravitational radiation in trans-Planckian scattering.
References:
[1] Himanshu Raj and Raju Venugopalan, arXIv:2311.03463
[2] Himanshu Raj and Raju Venugopalan, arXIv:2312.xxxxx