Conformal Moduli and b-c Pictures for NSR Strings

TL;DR

This paper investigates the geometry of superconformal moduli in NSR superstring theory to develop a consistent sigma-model, addressing picture-changing ambiguities and revealing global singularities linked to D-brane operators.

Contribution

It introduces a BRST-invariant formulation of b-c picture-changing operators and analyzes the superconformal moduli space structure, including singularities and non-perturbative effects.

Findings

Derived BRST-invariant picture-changing operators for open and closed strings

Identified global singularities in superconformal moduli spaces

Linked singularities to D-brane creation operators

Abstract

We explore the geometry of the superconformal moduli of the NSR superstring theory in order to construct the consistent sigma-model for the NSR strings, free of picture-changing ambiguities. The sigma-model generating functional is constructed by the integration over the bosonic and anticommuting moduli, corresponding to insertions of the vertex operators in scattering amplitudes. In particular, the integration over the bosonic moduli results in the appearance of picture-changing operators for the b-c system. Important example of the b-c pictures involves the unintegrated and integrated forms of the vertex operators. We derive the BRST-invariant expressions for the b-c picture-changing operators for open and closed strings and study some of their properties. We also show that the superconformal moduli spaces of the NSR superstring theory contain the global singularities, leading to the appearance of non-perturbative solitonic D-brane creation operators.