Type I background fields in terms of type IIB ones

TL;DR

This paper derives an effective closed type I superstring theory from open IIB superstring theory with specific boundary conditions that preserve N=1 supersymmetry, revealing background fields with new quadratic corrections.

Contribution

It explicitly solves boundary conditions in open IIB superstring theory to obtain an effective theory with novel quadratic background field corrections.

Findings

Effective theory is symmetric under world-sheet parity.

Background fields include known and quadratic corrections.

Effective theory identified as closed type I superstring theory.

Abstract

We choose such boundary conditions for open IIB superstring theory which preserve N=1 SUSY. The explicite solution of the boundary conditions yields effective theory which is symmetric under world-sheet parity transformation $\Omega:\sigma\to-\sigma$. We recognize effective theory as closed type I superstring theory. Its background fields,beside known $\Omega$ even fields of the initial IIB theory, contain improvements quadratic in $\Omega$ odd ones.