Spinning binary dynamics in cubic effective field theories of gravity

TL;DR

This paper investigates the dynamics of binary Kerr black holes with arbitrary spins within cubic gravity theories, deriving amplitudes and kicks to understand how parity-even and parity-odd deformations influence gravitational interactions.

Contribution

It introduces the first computation of binary black hole dynamics in cubic gravity, including all parity deformations, using amplitude methods and effective field theory techniques.

Findings

Derived tree-level Compton amplitudes for Kerr black holes in cubic gravity.

Computed leading-order momentum and spin kicks in cubic gravity.

Provided all-order spin deflection angles for aligned spins.

Abstract

We study the binary dynamics of two Kerr black holes with arbitrary spin vectors in the presence of parity-even and parity-odd cubic deformations of gravity. We first derive the tree-level Compton amplitudes for a Kerr black hole in cubic gravity, which we then use to compute the two-to-two amplitudes of the massive bodies to leading order in the deformation and the post-Minkowskian expansion. The required one-loop computations are performed using the leading singularity approach as well as the heavy-mass effective field theory (HEFT) approach. These amplitudes are then used to compute the leading-order momentum and spin kick in cubic gravity in the KMOC formalism. Our results are valid for generic masses and spin vectors, and include all the independent parity-even and parity-odd cubic deformations of Einstein-Hilbert gravity. We also present spin-expanded expressions for the momentum and spin kicks, and the all-order in spin deflection angle in the case of aligned spins.