Unitarized one-loop graviton-graviton scattering

Abstract

In this work we interpret the Einstein-Hilbert (EH) Lagrangian of gravitation asthe first term of a low-energy effective theory similar to those considered in thechiral Lagrangian approach to low-energy hadron physics or the electroweakchiral Lagragians describing the symmetry breaking sector of the StandardModel (SM). Starting from the one-loop computation of the elastic graviton-graviton scattering amplitude by Dunbar and Norridge, we unitarize the IRregularized partial waves by using the Inverse Amplitude Method (IAM). Thismethod enlarges the regime of applicability of the perturbative results to higherenergies of the order of the Plank scale M P and allows for the possibility ofpoles in the second Riemann which have the natural interpretation of dynamicalresonances. In this work we look for these possible resonances for the ++++and −−−− helicity channels and the J = 0, 2 and 4 partial waves.