Incoherent ϕ photo-production from deuteron in SPring-8∕LEPS

Abstract

We present measurements of differential cross sections and decay asymmetries of incoherent φ‐meson photo‐production from the deuteron at forward angles using linearly polarized photons beam in energy range from the production threshold to E = 2.4 GeV. The experiment was performed at the SPring‐8/LEPS facility. The differential cross section of incoherent production shows a large suppression compared with the free proton case. The reduction for the deuteron cannot be clearly explained in terms of simple isospin asymmetry. The decay asymmetry of incoherent φ photo‐production shows that the eta exchange process is small. Since the exclusive K+K−p cross section shows the same reduction with incoherent, both the proton and neutron cross section reduce similarly. Consequently, the π‐η interference effect is small too. The present results suggest that our understanding of φ photo‐production within a nucleus should be rearranged.