Photoproduction and Forbidden Decays of ϕ Mesons

Photoproduction of ϕ mesons from hydrogen and carbon was studied at 5.2 GeV by observing ϕ-->K⁺K^- decays. The results show that ϕ's are produced diffractively with a ϕ-nucleon cross section σ_ϕN=9.8^+2.9_-3.3 mb. In addition, 80 000 pion pairs were measured to search for the G-parity-nonconserving decay ϕ-->π⁺π^-. Assuming complete interference between ρ-->π⁺π^- and ϕ-->π⁺π^-, we found an upper limit of Γ_ϕ-->2πΓ_ϕ-->all=2.7×10^-4 at the 95% level.