The Massless Spectrum of Covariant Superstrings

TL;DR

This paper computes the complete cohomology of covariant superstrings at all ghost numbers, clarifying the structure of physical states using a novel grading approach in BRST quantization.

Contribution

It introduces a new grading-based method to accurately determine the cohomology of covariant superstrings at any ghost number.

Findings

Correct cohomology at all ghost numbers for open and closed superstrings

New current related to affine Lie algebra grading

Clarification of physical state conditions in covariant superstring theory

Abstract

We obtain the correct cohomology at any ghost number for the open and closed covariant superstring, quantized by an approach which we recently developed. We define physical states by the usual condition of BRST invariance and a new condition involving a new current which is related to a grading of the underlying affine Lie algebra.