# Hidden gauge reducibility of superstring field theory and Batalin-Vilkovisky master action

## TL;DR

This paper reveals a hidden gauge reducibility in superstring field theory, leading to modifications in the Batalin-Vilkovisky master action and the emergence of additional degrees of freedom in loop amplitudes.

## Contribution

It uncovers a previously unnoticed gauge structure in superstring field theory and demonstrates how it alters the BV master action and the associated physical implications.

## Key findings

- Existence of hidden gauge reducibility in superstring field theory
- Modification of the BV master action due to additional ghost-antighost fields
- Presence of extra propagating degrees of freedom in loop amplitudes

## Abstract

In this paper, we show that there exists a hidden gauge reducibility in superstring field theory based on the small dynamical string field $\Psi \in \mathcal{H}_{\beta \gamma }$ whose gauge variation is also small $\delta \Psi \in \mathcal{H}_{\beta \gamma }$. It requires additional ghost-antighost fields in the gauge fixed or quantum gauge theory, and thus changes the Batalin-Vilkovisky master action, which implies that additional propagating degrees of freedom appear in the loop superstring amplitudes via the gauge choice of the field theory. We present that the resultant master action can take a different and enlarged form, and that there exist canonical transformations getting it back to the canonical form. On the basis of the Batalin-Vilkovisky formalism, we obtain several exact results and clarify this underlying gauge structure of superstring field theory.