Gravitino one-loop contribution to Planckian Scattering

TL;DR

This paper analyzes one-loop superstring amplitudes to compute quantum corrections to high-energy gravitational scattering, showing gravitinos do not affect the classical large-distance behavior.

Contribution

It provides the first explicit calculation of one-loop superstring corrections to the eikonal at high energies and clarifies the role of gravitinos in these corrections.

Findings

One-loop superstring amplitude yields the first subleading high-energy correction.

Gravitinos do not contribute to the large-distance two-loop correction.

The two-loop correction has a universal classical interpretation.

Abstract

Corrections to the semiclassical approximation in nearly forward Planckian energy collisions are here reconsidered. Starting from the one-loop superstring amplitude, we are able to disentangle the first subleading high-energy contribution at large impact parameters, and we thus directly compute the one-loop correction to the superstring eikonal. We finally argue, on the basis of analyticity and unitarity, that gravitinos do not contribute at all to the large distance two-loop ACV correction, which thus acquires a universal ``classical'' interpretation.