Omega N Scattering Length From Omega Photoproduction On The Proton Near The Threshold

Although the. meson is one of the best established hadrons, its fundamental properties such as the interaction with the nucleon is not known yet due to the difficulties in realizing scattering experiments. Recently, we have performed high-precision photoproduction experiment of the omega meson from the proton near the threshold. The total cross sections are determined at incident energies ranging from 1.08 to 1.15 GeV. The 1/2 and 3/2 spin-averaged scattering length a(omega N) and effective range r(omega N) between the omega meson and nucleon are extracted from the excitation function of the total cross section using a model with the final-state omega N interaction based on the Lippmann-Schwinger equation. The obtained values are a(omega p) = (-0.97(-0.16)(+0.16)) +i (0.07(-0.14)(+0.15)) fm and r(omega p) = (+2.78(-0.54)(+0.68)) +i (-0.01(-0.50)(+0.46)) fm, suggesting a strong repulsion force.