# Explanation of the 17 MeV Atomki Anomaly in a $U(1)^\prime$-Extended 2-Higgs Doublet Model

## TL;DR

This paper proposes a $U(1)'$-extended 2-Higgs Doublet Model to explain the 17 MeV anomaly observed in Beryllium decay, aligning with experimental data and introducing a potential new gauge boson.

## Contribution

It introduces a novel $U(1)'$ extension with a 2-Higgs Doublet structure that can account for the Atomki anomaly while remaining consistent with other experimental results.

## Key findings

- Explains the 17 MeV Beryllium decay anomaly with a new gauge boson.
- Demonstrates compatibility with existing experimental constraints.
- Identifies specific charge and Yukawa interaction configurations.

## Abstract

Motivated by an anomaly observed in the decay of an excited state of Beryllium by the Atomki collaboration, we study an extension of the Standard Model with a gauged $U(1)'$ symmetry in presence of a 2-Higgs Doublet Model structure of the Higgs sector. We show that this scenario complies with a variety of experimental results and is able to explain the potential presence of a resonant spin-1 gauge boson, $Z'$, with a mass of 17 MeV in the Atomki experimental data, for appropriate choices of $U(1)'$ charges and Yukawa interactions.