The detection of gravitational waves by the LIGO-VIRGO collaboration has marked a transformative era in astronomy, providing groundbreaking insights into the cosmos and creating new pathways for exploration. At the same time, advancements in the classical limit of scattering amplitudes, particularly through the KMOC formalism, have enriched our understanding of compact binary systems.
In this talk, we will discuss scalar-tensor theories that hold both theoretical and phenomenological interest, with examples including the Einstein-scalar-Gauss-Bonnet and Dynamical Chern-Simons theories. We will provide a brief overview of how compact objects acquire scalar hair in these settings and give an on-shell description of scalar hair for arbitrarily spinning bodies. Additionally, we compute waveforms directly from scattering amplitudes, exploring the role of alternative gravity theories in radiation losses for spinning binary systems. By identifying deviations from Einstein’s theory, we aim to reveal distinctive signatures of these frameworks, offering insights into fundamental physics and new avenues for experimental tests.
