**Abstract:**

A remarkable double copy relation of Einstein gravity to QCD in Regge asymptotics is Γμν=12CμCν−12NμNν, where Γμν is the gravitational Lipatov vertex in the 2→3 graviton scattering amplitude, Cμ its Yang-Mills counterpart, and Nμ the QED bremssstrahlung vertex. In QCD, the Lipatov vertex is a fundamental building block of the BFKL equation describing 2→N scattering of gluons at high energies. Likewise, the gravitational Lipatov vertex is a key ingredient in a 2-D effective field theory framework describing trans-Planckian 2→N graviton scattering. We construct a quantitative correspondence between a semi-classical Yang-Mills framework for radiation in gluon shockwave collisions and its counterpart in general relativity. In particular, we demonstrate the Lipatov double copy in a dilute-dilute approximation corresponding to RS,L, RS,H ≪b, with RS,L, RS,H the respective emergent Schwarzchild radii generated in shockwave collisions and b is the impact parameter. We outline extensions of the correspondence developed here to the dilute-dense computation of gravitational wave radiation in close vicinity of one of the black holes, the construction of graviton propagators in the shockwave background, and a renormalization group approach to compute 2→N amplitudes that incorporates graviton reggeization and coherent graviton multiple scattering.

**H. Raj, R. Venugopalan, “Universal features of 2N scattering in QCD and gravity from shockwave
collisions”, Nov. 6, 2023, arXiv:2311.03463 (2023).**

https://arxiv.org/abs/2311.03463

Related to Project C05, Co6