Search for narrow six-quark states in the reactions \gamma d -->\pi\gamma NN

Abstract

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.