Diffractive $\phi$ photo-production off the Deuteron Near Threshold in LEPS/SPring-8

Measurement of $\phi$ photo-production off the deuteron at forward angles investigate an unique way of studying the reaction mechanisms. Close to production threshold, meson-exchange processes such as exchange of $\pi$ or $\eta$ shows up, other than the dominating channel of Pomeron exchange in the high energy region. The isovector $\pi$-meson exchange can be eliminated in coherent photoproduction from the deuteron as an isoscalar target. In the SPring-8/LEPS experiment, we have measured photo-production of $\phi$ from liquid deuteron target with a photon energy from production threshold to 2.4 GeV. Linearly polarized photon beam was generated by backward Compton scattering. In this talk, we will report preliminary results of differential cross section and decay asymmetry for both coherent and incoherent production.