Two-point functions of Neumann-Dirichlet open-string sector moduli

TL;DR

This paper calculates one-loop two-point functions of massless scalars in a specific open-string sector of a type IIB orientifold, revealing how moduli fields acquire mass when supersymmetry is broken.

Contribution

It introduces a method to evaluate boundary-changing vertex operator correlators for open strings, extending the understanding of moduli mass generation in string compactifications.

Findings

Computed one-loop masses for moduli fields in the N-D sector.

Established a connection between boundary-changing correlators and twist field correlators.

Provided insights into supersymmetry breaking effects on open-string moduli.

Abstract

We compute at one loop the two-point functions of massless scalars in the Neumann-Dirichlet open-string sector of the type IIB orientifold compactified on $T^2\times T^4/\mathbb{Z}_2$, when $\mathcal{N}=2$ supersymmetry is spontaneously broken. This is done by evaluating correlation functions of ``boundary-changing vertex operators'' which are analogous to correlators of twist fields for closed strings. We use our results to compute the mass developed at one loop by the moduli fields arising in the Neumann-Dirichlet sector.