Asymmetries in phi photoproduction and the OZI violation

We study the vector meson density matrix and the associated polarization asymmetries in $\phi$ photoproduction near threshold. In order to study the OZI violating processes, we consider the direct $\phi NN$ coupling as well as the knockout processes arising from the non-vanishing $s\bar{s}$ sea quarks in the nucleon. The polarization asymmetries in $\phi$ meson decays are found to be very useful to constrain the $\phi NN$ coupling constant. The hidden strangeness of the nucleon can also be studied by these asymmetries, but mostly at large $|t|$ region.