$\pi^0\gamma$ invariant mass distribution in the low energy $\gamma p \to \omega p$ reaction

Abstract

We study the reaction mechanism for the correlated $\pi^0\gamma$ emission in the photon induced reaction on the proton target. Since this reaction is studied in the GeV region, we assume that it proceeds through the formation of the vector meson in the intermediate state. The vector meson, being an unstable particle, decays into $\pi^0\gamma$ bosons after propagating certain distance. Our analysis shows that the $\pi^0\gamma$ event seen in coincidence in the final state dominantly arises due to the decay of $\omega$ meson. The calculated results reproduce the measured $\pi^0\gamma$ invariant mass distribution spectra very well.