Primakoff production of ${\pi }^0$, $\eta$ and ${\eta }^{\prime }$ in the Coulomb field of a nucleus

Abstract

Photoproduction of neutral pseudoscalar mesons ${\pi }^0,\eta (547)$ and ${\eta }^{\prime }(958)$ in the Coulomb field of an atomic nucleus is studied using a model which describes the Primakoff and nuclear parts of the production amplitude. At high energies the nuclear background is dominated by the exchange of $C$-parity odd Regge trajectories. In the coherent production the isospin filtering makes the $\omega (782)$ a dominant trajectory. The calculations are in agreement with ${\pi }^0$ data from JLAB provided the photon shadowing and final state interactions of mesons are taken into account. The kinematic conditions which allow to study the Primakoff effect in $\eta$ and ${\eta }^{\prime }$ photoproduction off nuclei are further discussed. We also give predictions for the higher energies available at the JLAB upgrade.

Comments: 15 pages, 14 figures, discussion added, final version to be published in Phys. Rev. C