Experimental investigation of high-energy photon splitting in atomic fields

TL;DR

This paper reports the first experimental observation of high-energy photon splitting in atomic fields, using a large photon dataset, and compares the results with theoretical predictions, confirming the accuracy of exact calculations over approximations.

Contribution

First experimental observation of photon splitting in atomic fields at high energies, with data analysis confirming exact theoretical cross sections.

Findings

Experimental results agree with exact atomic field calculations.

Born approximation predictions significantly differ from observed data.

Collected 1.6 billion photons and identified about 400 photon splitting candidates.

Abstract

The new data analysis of the experiment, where the photon splitting in the atomic fields has been observed for the first time, is presented. This experiment was performed at the tagged photon beam of the ROKK-1M facility at the VEPP-4M collider. In the energy region of 120-450 MeV, the statistics of $1.6\cdot 10^9$ photons incident on the BGO target was collected. About 400 candidates to the photon splitting events were reconstructed. Within the attained experimental accuracy, the experimental results are consistent with the cross section calculated exactly in an atomic field. The predictions obtained in the Born approximation significantly differ from the experimental results.