Radiation reaction force for scalar-tensor theories in effective-one-body formalism

TL;DR

This paper derives the radiation reaction force for eccentric nonspinning binaries in scalar-tensor theories within the EOB framework, enabling improved waveform modeling for gravitational wave detection.

Contribution

It provides the first derivation of radiation reaction forces for eccentric orbits in scalar-tensor theories up to 1.5PN order within the EOB formalism.

Findings

Derived radiation reaction force for eccentric orbits in scalar-tensor theories.

Identified 1.5PN order effects due to radiation reaction square effects.

Results can enhance waveform templates for gravitational wave detection.

Abstract

Whilst most of the binary configurations in modified theories of gravity are studied under quasi-circular orbit limit, eccentricity effects could play a significant role in future gravitational wave detections. We derive the gravitational radiation-reaction force for nonspinning eccentric orbits within the effective-one-body (EOB) description for the massless scalar-tensor theories up to 1.5 post-Newtonian (PN) order. The effects in such theories start at $1/c^3$ and interestingly, the 1.5PN order effect is due to the radiation reaction square effects which is a conservative effect. The results derived here can be implemented in the quasi-circular EOB-based waveform models to construct waveform templates for generic orbit binaries within massless scalar-tensor theories of gravity.