Near-threshold production of \(\omega\)-mesons in the \(pn\rightarrow d\omega\) reaction

The first measurement of the \(pn\rightarrow d\omega\) total cross-section has been achieved at mean excess energies \(Q\approx 28\) and 57 MeV by using a deuterium cluster-jet target. The momentum of the fast deuteron was measured in the ANKE spectrometer at COSY-Julich and that of the slow “spectator” proton \((p_{\rm {sp}})\) from the \(pd\rightarrow p_{\rm {sp}}d\omega\) reaction in a silicon telescope placed close to the target. The cross-sections lie above those measured for \(pp\rightarrow pp\omega\) but seem to be below theoretical predictions.