${\eta }^{\prime }$ production in proton-proton scattering close to threshold}

Abstract

The $pp\to pp{\eta }^{\prime }$ (958) reaction has been measured at COSY using the internal beam and the COSY-11 facility. The total cross sections at the four different excess energies \mbox{$Q=1.5MeV,1.7MeV,2.9MeV,$ and $4.1MeV$} have been evaluated to be \mbox{$\sigma =2.5\pm 0.5nb$, $2.9\pm 1.1nb$, $12.7\pm 3.2nb$, ~ and $25.2\pm 3.6nb$}, respectively. In this region of excess energy the ${\eta }^{\prime }$ (958) cross sections are much lower compared to those of the ${\pi }^0$ and $\eta$ production.

Comments: 11 pages, 3 figures