Graviton-Scalar Interaction in the PP-Wave Background

TL;DR

This paper calculates the graviton-two scalar interaction vertex in a pp-wave background within Type IIB superstring theory, demonstrating its vanishing on-shell and confirming results through supergravity analysis.

Contribution

It provides a detailed computation of the off-shell interaction vertex and confirms its on-shell vanishing using both string field theory and supergravity methods.

Findings

The off-shell vertex is computed explicitly.

The vertex vanishes on-shell under conservation laws.

Results are consistent between string theory and supergravity approaches.

Abstract

We compute the graviton two scalar off-shell interaction vertex at tree level in Type IIB superstring theory on the pp-wave background using the light-cone string field theory formalism. We then show that the tree level vertex vanishes when all particles are on-shell and conservation of p_{+} and p_{-} are imposed. We reinforce our claim by calculating the same vertex starting from the corresponding SUGRA action expanded around the pp-wave background in the light-cone gauge.