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

TL;DR

This paper models the photoproduction of neutral mesons $b5^0$, $b7$, and $b7'$ in the Coulomb field of nuclei, analyzing the Primakoff effect and nuclear background at high energies, with applications to JLAB experiments.

Contribution

It introduces a comprehensive model combining Primakoff and nuclear amplitudes, accounting for Regge exchanges and shadowing, to interpret meson photoproduction data.

Findings

Agreement with JLAB $b0$ data when including shadowing and final state interactions

Predictions for $b7$ and $b7'$ production at higher energies

Identification of kinematic conditions for studying the Primakoff effect

Abstract

Photoproduction of neutral pseudoscalar mesons $\pi^0,\eta(547)$ and $\eta'(958)$ 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 $\eta'$ photoproduction off nuclei are further discussed. We also give predictions for the higher energies available at the JLAB upgrade.