A Model for High Energy Scattering in Quantum Gravity

TL;DR

This paper models high energy quantum gravity scattering, highlighting black hole formation at small impact parameters and eikonalized graviton exchange at larger distances, with implications for low-scale quantum gravity theories.

Contribution

It introduces a model for high energy scattering in quantum gravity that incorporates black hole formation and decay, extending previous approaches with a focus on impact parameter regimes.

Findings

Black hole formation dominates at small impact parameters.

Elastic scattering is suppressed at small impact parameters.

Eikonalized graviton exchange describes large impact parameter scattering.

Abstract

We present a model for high energy two body scattering in a quantum theory of gravity. The model is applicable for center of mass energies higher than the relevant Planck scale. At impact parameters smaller than the Schwarzchild radius appropriate to the center of mass energy and total charge of the initial state, the cross section is dominated by an inelastic process in which a single large black hole is formed. The black hole then decays by Hawking radiation. The elastic cross section is highly suppressed at these impact parameters because of the small phase space for thermal decay into a high energy two body state. For very large impact parameter the amplitude is dominated by eikonalized single graviton exchange. At intermediate impact parameters the scattering is more complicated, but since the Schwarzchild radius grows with energy, we speculate that a more sophisticated eikonal calculation which uses the nonlinear classical solutions of the field equations may provide a good approximation at all larger impact parameters. We discuss the extent to which black hole production will be observable in theories with low scale quantum gravity and large dimensions.