Seeking for resonances in unitarized one-loop graviton-graviton scattering

Abstract

Some effective field theories exhibit dynamical resonances that, when properly included, mitigate their bad behavior at high energies. Unitarization of the partial wave amplitudes is the preferred method to unveil such resonances. Interpreting the Einstein-Hilbert theory in the spirit of effective Lagrangians, we implement the inverse amplitude method and unitarize the one-loop level graviton-graviton scattering in pure gravity. Due to the presence of infrared divergences, the analysis requires a careful treatment of the infrared region and the introduction of infrared regulators, carefully selected in order to fulfill perturbative unitarity.