The W-string spectrum
Kellogg S. Stelle · AIP conference proceedings · 1992
Anomaly‐free strings with local worldsheet symmetries described by W algebras have some coordinates that are frozen by the gauge constraints so that they have only discrete allowable values of momenta. This gives rise to a branched structure of the overall spectrum. A subset of the spectrum corresponds to the states of an ordinary noncritical bosonic string. However, there are also new kinds of physical states involving the frozen coordinates and also the ghost fields.