Differential cross sections and photon beam asymmetries for the reaction γp→π0p have been measured in the photon beam energy range of 1.3-2.4GeV and the π0 polar angle range of -1<cosθπ0c.m.<0.7. The measurement has been done by using a large acceptance electromagnetic calorimeter in the SPring-8 LEPS2/BGOegg experiment. The results of the photon beam asymmetry in a wide π0 polar angle range are new for the photon beam energies exceeding 1.9GeV. None of the existing partial wave analysis models describe the observed asymmetries in the high energy region. The contribution of multipole amplitudes with an orbital angular momentum of 5 in the πN system has been found to be important at these energies.
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© 2019 American Physical Society.
ASJC Scopus subject areas
- Nuclear and High Energy Physics