  We propose to describe bulk wave functions of fractional quantum Hall states
in terms of correlators of non-unitary b/c-spin systems. These yield a
promising conformal field theory analogon of the composite fermion picture of
Jain. Fractional statistics is described by twist fields which naturally appear
in the b/c-spin systems. We provide a geometrical interpretation of our
approach in which bulk wave functions are seen as holomorphic functions over a
ramified covering of the complex plane, where the ramification precisely
resembles the fractional statistics of the quasi-particle excitations in terms
of branch points on the complex plane. To extend Jain's main series, we use the
concept of composite fermions pairing to spin singlets, which enjoys a natural
description in terms of the particular c=-2 b/c-spin system as known from the
Haldane-Rezayi state. In this way we derive conformal field theory proposals
for lowest Landau level bulk wave functions for more general filling fractions.
We obtain a natural classification of the experimentally confirmed filling
fractions which does not contain prominent unobserved fillings. Furthermore,
our scheme fits together with classifications in terms of K-matrices of
effective multilayer theories leading to striking restrictions of these
coupling matrices.
