Polarization of Recoil Protons from the Photoproduction of Eta-Meson

Abstract

The polarization of recoil protons from the reaction γ+p→p+η⁰ was measured for eta center of mass angle of 107.5° at 890 MeV γ-ray energy.
The decay γ-rays from η⁰ were detected by a lead glass Cerenkov counter in coincidence with a recoil proton. Recoil proton polarization was measured by analysing the scattering asymmetry in a carbon plate spark chamber.
According to Minami’s theoretical analysis for the interpretation of the eta-nucleon system, the obtained value of the polarization P=0.54±0.40 is suggesting that the contribution of the interaction in the S_1⁄2 state is predominant over that in the D_3⁄2 state.