Muon-to-electron conversion in mirror fermion model with electroweak scale non-sterile right-handed neutrinos
P.Q. Hung (Center for Theoretical and Computational Physics, Hue University College of Education, Hue, Viet Nam, Department of Physics, University of Virginia, Charlottesville, USA); Trinh Le (Department of Physics, University of Virginia, Charlottesville, USA); Van Que Tran (Department of Physics, National Taiwan Normal University, Taipei, Taiwan); Tzu-Chiang Yuan (Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan, Institute of Physics, Academia Sinica, Nangang, Taiwan)
The muon-to-electron conversion in aluminum, titanium and gold nuclei is studied in the context of a class of mirror fermion model with non-sterile right-handed neutrinos having masses at the electroweak scale. We show that the electric and magnetic dipole operators from the photon exchange diagrams provide the dominant contributions, which enables us to derive a simple formula to relate the conversion rate with the on-shell radiative decay rate of muon into electron at the limit of zero momentum transfer and large mirror lepton masses. Current experimental limits (SINDRUM II) and projected sensitivities (Mu2e, COMET and PRISM) for the muon-to-electron conversion rates in various nuclei and latest limit from MEG for the radiative decay rate of muon into electron are used to put constraints on the parameter space of the model. Sensitivities to the new Yukawa couplings can reach the range of one tenth to one hundred-thousandth, depending on the mixing scenarios and mirror fermion masses in the model as well as the nuclei targets used in future experiments.
