Explaining ATOMKI, $(g-2)_μ$, and MiniBooNE anomalies with light mediators in $U(1)_H$ extended model

Abstract: We consider $U(1)_H$ extensions of Type-I 2HDM plus a singlet scalar $\phi_H$, introducing a new Higgs doublet $H_2$ and a singlet $\phi_H$ charged under $U(1)_H$. The SM Higgs doublet $H_1$ as well as all the SM fermions and three right-handed singlet neutrinos, introduced to generate nonzero neutrino masses and mixings, are neutral under $U(1)_H$. We also introduce a SM singlet Dirac fermion, charged under $U(1)_H$ and utilize it as sterile neutrinos relevant to the MiniBooNE experiment. The $U(1)_H$ symmetry breaks due to the vacuum expectation values of $H_2$ and $\phi_H$, leading to the emergence of a light vector boson with a mass of approximately 17 MeV. This vector boson interacts with fermions through mass mixing and kinetic mixing process involving other neutral gauge bosons. Furthermore, alongside the light vector boson, another light scalar particle with a mass around 10--100 MeV may arise from scalar sector mixing. By utilizing the gauge couplings of the light vector boson and the Yukawa couplings of the light scalar, this model can simultaneously provide an explanation for the Beryllium anomaly observed in the ATOMKI experiment, the anomalous magnetic moment of charged leptons and the excess of electron-like events detected at the MiniBooNE experiment.