Inelastic exponentiation and classical gravitational scattering at one loop
Alessandro Georgoudis, Carlo Heissenberg, Ingrid A. Vazquez-Holm
Abstract
A bstract We calculate the inelastic 2 → 3 one-loop amplitude for the scattering of two point-like, spinless objects with generic masses involving the additional emission of a single graviton. We focus on the near-forward, or classical, limit. Our results include the leading and subleading orders in the soft-region expansion, which captures all non-analytic contributions in the transferred momentum and in the graviton’s frequency. This allows us to check the first constraint arising from the inelastic exponentiation put forward in refs. [1–3], and to calculate the 2 → 3 one-loop matrix element of the N -operator, linked to the S -matrix by S = e iN , showing that it is real, classical and free of infrared divergences. We discuss how our results feature in the calculation of the $$ \mathcal{O} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> </mml:math> ( G 3 ) corrections to the asymptotic waveform.