First measurement of coherent $\phi$-meson photoproduction on deuteron

\newcommand{\sigphin}{$\sigma_{\phi N}$} \newcommand{\gevc}{~GeV$^2$/c$^2$} Coherent $\phi$-meson photoproduction on deuteron is studied in a high-statistics photo-deuteron experiment at CLAS with a tagged photon beam ($E_{\gamma}=$ 0.8 -- 3.6~GeV). The cross section and decay angular distributions have been measured for the first time up to a squared four-momentum transfer $t = (p_{\gamma}-p_{\phi})^2 =-2$\gevc. The cross sections are compared with predictions from a re-scattering model. In the framework of vector meson dominance (VMD), the data are consistent with the total $\phi$-N cross section \sigphin ~at about 10~mb. If vector meson dominance is violated, a larger \sigphin ~from the A-dependence experiment~[1] is possible by introducing a larger $t$-slope for the $\phi N\rightarrow\phi N$ process than that for the $\gamma N\rightarrow\phi N$ process. The decay angular distributions follow the prediction from helicity conservation. This measurement demonstrates a new approach to the study of the $\phi$-N interaction in the energy region where VMD may not be a good approximation.\\ ~[1]~ T.~Ishikawa, {\it et al.} Phys. Lett. {\bf B608}, 215 (2005).