High energy scattering in gravity and supergravity

Understand

We investigate features of perturbative gravity and supergravity by studying scattering in the ultraplanckian limit, and sharpen arguments that the dynamics is governed by long-distance physics.

• A simple example capturing aspects of the eikonal resummation suggests why short distance phenomena and in particular divergences or nonrenormalizability do not necessarily play a central role in this regime.
• A more profound problem is apparently unitarity.
• These considerations can be illustrated by showing that known gravity and supergravity amplitudes have the same long-distance behavior, despite the extra light states of supergravity, and this serves as an important check on long-range dynamics in a context where perturbative amplitudes are finite.