Photoproductions of $f_1(1285)$ and ${\eta }^{\prime }(958)$ from the analysis of CLAS data with the Primakoff effect at high energies

Abstract

We investigate photoproduction of axial vector meson $f_1(1285)$ based on the CLAS experiment $\gamma p\to p{f}_1(1285)\to p\eta {\pi }^{+}{\pi }^{-}$ using the Regge model for ${\rho }^0+\omega$ exchanges. The combined analysis of $\gamma p\to p{\eta }^{\prime }\to p\eta {\pi }^{+}{\pi }^{-}$ reaction including $\eta (1295)$ is accompanied to evaluate the decay mode $\eta (1295)\to \eta {\pi }^{+}{\pi }^{-}$ from the potential overlap with the $f_1$ reaction. The predominance of ${\rho }^0(770)$ exchange over the $\omega (782)$ with the coupling constant $\gamma {\rho }^0{f}_1$ extracted from the CLAS experiment leads to a good description of the measured cross sections for $f_1$, while the scale of the cross section is corrected by the branching fraction ${\eta }^{\prime }\to \eta {\pi }^{+}{\pi }^{-}$, and $f_1\to \eta {\pi }^{+}{\pi }^{-}$, respectively. As an extension to study the nonmesonic production mechanism, the Primakoff effect by the virtual photon exchange is investigated in the exclusive reaction $\gamma p\to p{f}_1$ up to $\sqrt{s}\approx 50$ GeV, finding that it plays a similar role to the Pomeron in the vector meson photoproduction at high energies. Such an unique role of the virtual photon exchange similar to the $f_1$ case is identified up to $\sqrt{s}\approx 250$ GeV in the $\gamma p\to p{\pi }^0$ and $\gamma p\to p\eta$ as well as $\gamma p\to p{\eta }^{\prime }$ reaction.

Comments: 10 pages, 11 figures, 2 tables