Gauge-covariant vertex operators

TL;DR

This paper derives gauge-covariant vertex operators for superstring theory that are BRST invariant without fixing a gauge, enabling direct computation of gauge-invariant three-point vertices using conformal field theory methods.

Contribution

It introduces a new approach to constructing BRST-invariant vertex operators that do not depend on gauge fixing, simplifying calculations in string theory.

Findings

BRST invariance achieved with free gauge-covariant equations

Three-point vertices obtained in gauge-invariant form

Method simplifies string theory vertex computations

Abstract

We derive Yang-Mills vertex operators for (super)string theory whose BRST invariance requires only the free gauge-covariant field equation and no gauge condition. Standard conformal field theory methods yield the three-point vertices directly in gauge-invariant form.