Critically Analyzing the Existence of the X17 Particle

The X17 particle is a hypothetical protophobic boson proposed in 2016 by Krasznahorkay et al. at the Institute for Nuclear Research, Hungarian Academy of Sciences (ATOMKI) in order to explain excess decays in the production of e^-/e⁺ pairs by certain nuclear transitions. While the implications of such a particle have been connected to dark matter and ‘the fifth force,’ various critiques, including the inability by others to reproduce the signal, suggest that the proposed X17 particle must be treated with some skepticism. In this work, we present and analyze simulations probing ATOMKI’s work. In particular, we simulate electron and positron events within the relevant geometry of ATOMKI’s experimental apparatus, focusing on the asymmetry of e^-/e⁺ detector efficiency combined with various other quantities which could help to explain the X17 signal within the Standard Model. We conclude that ATOMKI’s setup manifests some discriminatory effects for e^-/e⁺, strengthening the possibility of a Standard Model explanation for the X17 signal and prompting further investigation.