Measurement of the beam-helicity asymmetry in photoproduction of π0η pairs on carbon, aluminum, and lead

Abstract The beam-helicity asymmetry was measured, for the first time, in photoproduction of π 0 η pairs on carbon, aluminum, and lead, with the A2 experimental setup at MAMI. The results are compared to an earlier measurement on a free proton and to the corresponding theoretical calculations. The Mainz model is used to predict the beam-helicity asymmetry for the nuclear targets. The present results indicate that the photoproduction mechanism for π 0 η pairs on nuclei is similar to photoproduction on a free nucleon. This process is dominated by the D 33 partial wave with the η Δ ( 1232 ) intermediate state.