Production ofπ∘Mesons byγ-Rays on Hydrogen

Abstract

The production of ${\pi }^{\circ }$ mesons in the reaction $\gamma +p\to {\pi }^{\circ }+p$ is investigated as a function of the incident $\gamma$-ray energy in the region from 200 Mev to 300 Mev. For the ${\pi }^{\circ }$ emitted at approximately 90° laboratory angle, the differential cross section can be represented by ${\left(\frac{d{{\sigma }_{\pi }}^{\circ }}{d\Omega }\right)}_{\frac{\pi }{2}}=C{\mathrm{}(K-145\mathrm{})\mathrm{}}^{1.9\pm 0.4},$ where $K$= energy of incident $\gamma$-ray in Mev. The approximate threshold for the reaction is 145 Mev.