Differential cross sections and photon beam asymmetries of photoproduction on the proton at = 1.3-2.4 GeV

Hashimoto, Toshikazu*; Tsuchikawa, Yusuke ; LEPS BGOegg Collaboration*; 58 of others*

We report exclusive measurements for the photoproduction on a proton target. The differential cross sections and photon beam asymmetries of the reaction are measured in a center-of-mass energy () range of 1.82-2.32 GeV and a polar angle range of by using a large acceptance calorimeter (BGOegg) and forward-angle charged-particle detectors at the SPring-8 LEPS2 beamline. The reaction is identified with a kinematic fitting method to select a recoil proton and two photons produced in an meson decay. A bump structure at W = 2.0-2.3 GeV in the differential cross section is confirmed at extremely backward polar angles, where the existing data are inconsistent with each other. This bump structure is likely associated with high-spin resonances that couple with quarks. The photon beam asymmetries in a wide polar angle range for the photon beam energies above 2.1 GeV are reported for the first time, providing an additional constraint to nucleon resonance studies at high energies.