  We study the reactions \gamma d --> \pi\gamma NN with the aim to search for
six-quark states, the decay of which into two nucleons is forbidden by the
Pauli exclusion principle. Such states predicted by a variety of QCD inspired
models and recent evidence from Proton Linear Accelerator of INR (Moscow)
strongly suggests the existence of such states with masses 1904, 1926, and 1942
MeV. We propose an experiment at MAMI-B which will provide a unique opportunity
to observe such dibaryon states in mass region up to 2000 MeV and determine
their masses and quantum numbers.
