Omega- and phi-meson production in p n ->d M reactions near threshold and OZI-rule violation

We investigate the reactions p n ->d omega and p n ->d phi close to the corresponding thresholds. The S-wave amplitudes are calculated within the framework of the two-step model which is described by a triangle graph with pi, rho and omega mesons in the intermediate state. The cross sections of the reactions p n ->d omega and p n ->d phi are predicted to be significantly larger than the cross sections of the corresponding reactions p p ->p p omega and p p ->p p phi at the same values of the c.m. excess energy Q. The ratio of the yields of phi to omega is found to be (30 +/- 7) x 10^-3.