Near-threshold production of ω -mesons in the pn→ dω reaction

. The first measurement of the pn→ dω total cross-section has been achieved at mean excess energies Q≈ 28 and 57 MeV by using a deuterium cluster-jet target. The momentum of the fast deuteron was measured in the ANKE spectrometer at COSY-Jülich and that of the slow “spectator” proton (p_sp) from the pd→ p_spdω reaction in a silicon telescope placed close to the target. The cross-sections lie above those measured for pp→ ppω but seem to be below theoretical predictions.