  We study the coupled pion-nucleon system (negative parity, isospin 1/2) based
on a lattice QCD simulation for nf=2 mass degenerate light quarks. Both,
standard 3-quarks baryon operators as well as meson-baryon (4+1)-quark
operators are included. This is an exploratory study for just one lattice size
and lattice spacing and at a pion mass of 266 MeV. Using the distillation
method and variational analysis we determine energy levels of the lowest
eigenstates. Comparison with the results of simple 3-quark correlation studies
exhibits drastic differences and a new level appears. A clearer picture of the
negative parity nucleon spectrum emerges. For the parameters of the simulation
we may assume elastic s-wave scattering and can derive values of the phase
shift.
