Universal features of 2 → N scattering in QCD and gravity from shockwave collisions

Journal Article · 27 February 2024 · Physical Review. D.

DOI: https://doi.org/10.1103/physrevd.109.044064 · OSTI ID:2315056

Raj, Himanshu ^[1]; Venugopalan, Raju ^[2]

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1. Université Paris-Saclay, Gif-sur-Yvette (France); Centre National de la Recherche Scientifique (CNRS) (France); Stony Brook Univ., NY (United States)
2. Brookhaven National Laboratory (BNL), Upton, NY (United States); Stony Brook Univ., NY (United States)

A remarkable double-copy relation of Einstein gravity to QCD in Regge asymptotics is Γ^μν = $$\tfrac{1}{2}$$C^μC^ν - $$\tfrac{1}{2}$$N^μN^ν, where Γ^μν is the gravitational Lipatov vertex in the 2 → 3 graviton scattering amplitude, C^μ its Yang-Mills counterpart, and N^μ the QED bremsstrahlung vertex. In QCD, the Lipatov vertex is a fundamental building block of the BFKL equation describing the 2 → N scattering of gluons at high energies. Likewise, the gravitational Lipatov vertex is a key ingredient in a 2D effective field theory framework describing trans-Planckian 2 → N graviton scattering. We construct a quantitative correspondence between a semiclassical 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 R_S,L, R_S,H $$\ll$$ b, where R_S,L, R_S,H are 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 the 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.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP); USDOE Laboratory Directed Research and Development (LDRD) Program
• Grant/Contract Number: SC0012704
• OSTI ID: 2315056
• Alternate ID(s): OSTI ID: 2324882
• Report Number(s): BNL-225391-2024-JAAM; TRN: US2409743
• Journal Information: Physical Review. D., Vol. 109, Issue 4; ISSN 2470-0010
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English