Primakoff effect in eta-photoproduction off protons

TL;DR

This paper uses the Primakoff effect in eta-photoproduction off protons to extract the eta to gamma gamma decay width, constraining hadronic amplitudes with existing data and providing predictions for future experiments.

Contribution

It introduces a method to determine the eta decay width via the Primakoff effect, integrating a global fit to gamma p to p eta data for improved accuracy.

Findings

Extracted eta to gamma gamma decay width consistent with literature

Constrained hadronic amplitude using global fit to existing data

Provided predictions for upcoming Jefferson Laboratory experiments

Abstract

We analyse data on forward eta-meson photoproduction off a proton target and extract the eta to gamma gamma decay width utilizing the Primakoff effect. The hadronic amplitude that enters into our analysis is strongly constrained because it is fixed from a global fit to available gamma p to p eta data for differential cross sections and polarizations. We compare our results with present information on the two-photon eta-decay from the literature. We provide predictions for future PrimEx experiments at Jefferson Laboratory in order to motivate further studies.