X17 discovery potential in the $\gamma N \rightarrow e^+ e^- N$ process at electron scattering facilities

TL;DR

This paper explores the potential to detect the X17 particle, hypothesized to explain certain nuclear anomalies, through dilepton photoproduction at electron scattering facilities, estimating signal strength and background ratios.

Contribution

It proposes a novel experimental approach to search for X17 via dilepton photoproduction, considering different quantum number scenarios and existing experimental constraints.

Findings

Signal-to-background ratio up to ten times for neutron targets.

Higher detectability for pseudoscalar and vector X17 scenarios.

Feasible detection with current dilepton resolution capabilities.

Abstract

We propose a direct search for the X17 particle, which was conjectured to explain the ATOMKI $^8$Be and $^4$He anomalies, through the dilepton photoproduction process on a nucleon in the photon energy range below or around the pion production threshold. For the scenarios of either pseudoscalar, vector, or axial-vector quantum numbers of the conjectured X17, we use existing constraints to estimate the X17 signal process. For dilepton resolutions which have been achieved in previous experiments, a signal-to-background ratio of up to an order of magnitude is found for a neutron target, and in particular for the pseudoscalar and vector X17 scenarios.