Photoproduction of a New Vector Meson by Linearly Polarized 9.3 GeV Gamma Rays

From a 275 events/μb exposure of the 82″ HBC to the SLAC linearly polarized monochromatic (9.3 GeV) γ beam, our preliminary analysis shows evidence for peripheral [exp (6t)] photoproduction of a JP = 1 −, meson with mass in the 1.5 GeV region, width ≳ 0.4 GeV (M and Γ both model dependent) and σ = 1.7 ± 0.3 μb in the reaction γp ⇒ ρ1 p, ρ1 ⇒ 2π+;2π−. The 4π system shows ρ0π+ π− substructure. Arguments for IG = 1+ are presented from the angular correlations (and the lack of clear evidence for a ρ0ρ0 decay mode).