  By using the hybrid formalism, superstrings in four-dimensional NS-NS plane
waves are studied in a manifest supersymmetric manner. This description of the
superstring is obtained by a field redefinition of the RNS worldsheet fields
and defined as a topological N=4 string theory. The Hilbert space consists of
two types of representations describing short and long strings. We study the
physical spectrum to find boson-fermion asymmetry in the massless spectrum of
the short string. Some massive spectrum of the short string and the massless
spectrum of the long string are also studied.

High Energy Physics - Theory