Identification and analysis of thenp→dη cross section near threshold

It is demonstrated that existing np→dX data show a strong signal for the two-body reaction np→dη near its threshold. The cross sectio n is much larger than that for the analogous ${\mathrm{\pi }}^0$ threshold production, but is in accord with a model where production is dominated by the ${\mathit{S}}_{11}$ ${\mathit{N}}^{\mathrm{*}}$(1535) resonance. The Abashian-Both-Crowe enhancement ${\mathit{X}}_{\mathrm{ABC}}$ is a prominent feature of the data. It is shown that the np→${\mathit{dX}}_{\mathrm{ABC}}$ process at 1.9 GeV/c, which contains most of the 2π production, is almost isotropic, in constrast to theoretical models.