The role of $N^{\ast }(1535)$ in ${\eta }^{\prime }$ production

Abstract

We study the near-threshold ${\eta }^{\prime }$ production mechanism in nucleon-nucleon and $\pi N$ collisions under the assumption that sub-threshold resonance $N^{\ast }(1535)$ is predominant. In an effective Lagrangian approach which gives a reasonable description to the $pN\to pN\eta$ and $\pi p\to p\eta$ reactions, it is found that t-channel $\pi$ exchange make the dominate contribution to the $pN\to pN{\eta }^{\prime }$ process, and a value of 6.5 for the ratio of $\sigma (pn\to pn{\eta }^{\prime })$ to $\sigma (pp\to pp{\eta }^{\prime })$ is predicted. A strong coupling strength of $N^{\ast }(1535)$ to ${\eta }^{\prime }N$ ($g_{{\eta }^{\prime }N{N}^{\ast }}^2/4\pi =1.1$) is extracted from a combined analysis to $pp\to pp{\eta }^{\prime }$ and $\pi N\to N{\eta }^{\prime }$, and the possible implication to the intrinsic component of $N^{\ast }(1535)$ is explored.

Comments: 12pp + 5figs