Testing the hypothesis of vector X17 boson by D meson, Charmonium, and $\phi$ meson decays

TL;DR

This study investigates the potential role of the X17 boson in various meson decays, fitting coupling parameters to experimental data, and finds tensions with previous ATOMKI measurements, providing predictions for unmeasured decay rates.

Contribution

It offers a detailed analysis of X17 boson contributions to meson decays, fitting coupling parameters independently, and highlights discrepancies with earlier experimental results.

Findings

Fitted coupling |5_c|=7.653, |5_s|=2.453, and a large |5_u|, conflicting with ATOMKI data.

Predicted the decay rate for D^{*+} 5 D^{+} e^+ e^- based on fitted parameters.

Identified tension between meson decay data and ATOMKI measurements regarding the X17 boson.

Abstract

The recent ATOMKI experiments provided evidence pointing towards the existence of an X17 boson in the anomalous nuclear transitions of Beryllium-8, Helium-4, and Carbon-12. In this work, we consider X17 boson contributions to the previously measured $D$ meson decays which include $D_s^{*+} \rightarrow D_s^+ e^+ e^-$, $D_s^{*+} \rightarrow D_s^+ \gamma$, $D^{*0} \rightarrow D^0 e^+ e^-$, and $D^{*0} \rightarrow D^0 \gamma$, as well as the measured decays of $\psi(2S) \rightarrow \eta_c e^+ e^-$, $\psi(2S) \rightarrow \eta_c \gamma$, $\phi \rightarrow \eta e^+ e^-$, and $\phi \rightarrow \eta \gamma$. Using the data of the above meson decays, we perform a fitting to the coupling parameters $\varepsilon_u, \varepsilon_c$, and $\varepsilon_s$ by treating the couplings $\varepsilon_u$ and $\varepsilon_c$ as independent from each other rather than assuming the generation universality $\varepsilon_u =\varepsilon_c$. It is found that the above fitting renders $|\varepsilon_c|=7.6\times 10^{-3}$, $|\varepsilon_s|=2.4\times 10^{-3}$ and a huge magnitude for $\varepsilon_u$, which is in serious tension with $\left|\varepsilon_u\right|$ determined from ATOMKI measurements. Using our fitted range for $\varepsilon_c$ and the range for $\varepsilon_d$ from ATOMKI measurements, we predict the range for $D^{*+} \rightarrow D^{+} e^+ e^-$ decay rate.