Where to find $X(17)$?

TL;DR

This paper investigates the hypothetical $X(17)$ particle proposed to explain the Atomki anomaly, using multiple experimental data sources to constrain its possible couplings, and finds no viable parameter space supporting its existence.

Contribution

The study provides comprehensive constraints on $X(17)$ couplings to electrons, challenging the particle's viability as a new physics signal based on current experimental data.

Findings

No viable parameter space for $X(17)$ models with various couplings.

Atomki anomaly unlikely due to new physics, possibly a nuclear effect.

Constraints derived from multiple experiments rule out $X(17)$ as an explanation.

Abstract

The Atomki anomaly puts forward the hypothesis of an $X(17)$ particle to explain the observation. Utilizing experimental data from the Atomki experiments, measurements of the electron's anomalous magnetic moment, beam dump experiments, the KLOE-2 experiment, the PADME experiment, and the parity-violating M{\o}ller scattering experiment, we derive constraints on the couplings of the $X(17)$ boson to electrons. Our findings indicate that no viable parameter spaces exist for the pseudoscalar, scalar, vector, axial-vector, and vector$\pm$axial-vector models describing the couplings of $X(17)$ to electrons. The Atomki anomaly may not correspond to signals of New Physics, but rather to some nuclear effect that remains poorly understood.