Contact terms, symmetries and D-instantons

TL;DR

This paper investigates how boundary contact terms are essential for maintaining gauge invariance, supersymmetry, and symmetry in the scattering of NS-NS antisymmetric tensor states with D-instantons in type IIB superstring theory.

Contribution

It demonstrates the necessity of including boundary contact terms to preserve fundamental symmetries in string scattering processes involving D-instantons.

Findings

Boundary contact terms are required for gauge invariance.

Supersymmetry and picture changing symmetry are preserved with contact terms.

The study clarifies the role of contact terms in string scattering amplitudes.

Abstract

The scattering of NS-NS antisymmetric tensor states in the presence of D-instantons in type IIB superstring theory is studied. It is shown that in order to preserve gauge invariance, spacetime supersymmetry and picture changing symmetry the inclusion of boundary contact terms for closed string antisymmetric tensor vertex operators is necessary.