Probing the ATOMKI X17 vector boson using Dalitz decays <i>V</i> → <i>Pe</i> ⁺ <i>e</i> ⁻ *

Abstract Recent anomalies observed in nuclear transitions of , , and by the ATOMKI collaboration may hint at the existence of a vector boson with a mass around 17 MeV, which is referred to as X17. If it exists, this boson would affect similar processes in particle physics, including the Dalitz decays of vector mesons. Recently, the BESIII collaboration measured the Dalitz decay for the first time and reported a excess over the theoretical prediction based on the vector meson dominance (VMD) model. This excess may be another signal of X17. In this study, we investigate the possible effects of X17 on the Dalitz decays , , and . The required hadronic form factors are calculated within the framework of our covariant confined quark model without relying on heavy quark effective theory or the VMD model. We present predictions for the Dalitz decay widths and the ratios within the standard model and in several new physics scenarios involving modifications attributed to X17. Our results are compared with other theoretical calculations.