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Abstract
Abstract
We investigate a new type of a two-Higgs-doublet model as a solution of the muon g - 2 anomaly. We impose a softly-broken Z 4 symmetry to forbid tree level flavor changing neutral currents in a natural way. This Z 4 symmetry restricts the structure of Yukawa couplings. As a result, extra Higgs boson couplings to muons are enhanced by a factor of tan [beta], while their couplings to all the other standard model fermions are suppressed by cot [beta]. Thanks to this coupling property, we can avoid the constraint from leptonic [tau] decays in contrast to the lepton specific two-Higgs-doublet model, which can explain the muon g - 2 within the 2[sigma] level but cannot within the 1[sigma] level due to this constraint. We find that the model can explain the muon g - 2 within the 1[sigma] level satisfying constraints from perturbative unitarity, vacuum stability, electroweak precision measurements, and current LHC data.
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1 Institute for Advanced Research, Nagoya University, Nagoya, Aichi, Japan; Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya, Aichi, Japan
2 Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot, Israel
3 INFN, Sezione di Firenze, and Department of Physics and Astronomy, University of Florence, Sesto Fiorentino, Italy