  The pp -> p K+ Y0 reaction has been studied for hyperon masses m(Y0)<1540
MeV/c2 at COSY-Juelich by using a 3.65 GeV/c circulating proton beam incident
on an internal hydrogen target. Final states comprising two protons, one
positively charged kaon and one negatively charged pion have been identified
with the ANKE spectrometer. Such configurations are sensitive to the production
of the ground state Lambda and Sigma0 hyperons as well as the Sigma0(1385) and
Lambda(1405) resonances. Applying invariant- and missing-mass techniques, the
two overlapping excited states could be well separated, though with limited
statistics. The shape and position of the Lambda(1405) distribution,
reconstructed cleanly in the Sigma0 pion0 channel, are similar to those found
from other decay modes and there is no obvious mass shift. This finding
constitutes a challenging test for models that predict Lambda(1405) to be a
two-state resonance.
