Neutrino mass in a gauged L μ  −  L τ model

Chen, Chuan-Hung (Department of Physics, National Cheng-Kung University, Tainan, 70101, Taiwan) ; Nomura, Takaaki  (School of Physics, KIAS, Seoul, 02455, Republic of Korea)

31 January 2019

Abstract: We study the origin of neutrino mass through lepton-number violation and spontaneous U(1)Lμ−Lτ symmetry breaking. To accomplish the purpose, we include one Higgs triplet, two singlet scalars, and two vector-like doublet leptons in the U(1)Lμ−Lτ gauge extension of the standard model. To completely determine the free parameters, we employ the Frampton–Glashow–Marfatia (FGM) two-zero texture neutrino mass matrix as a theoretical input. It is found that when some particular Yukawa couplings vanish, an FGM pattern can be achieved in the model. Besides the explanation of neutrino data, we find that the absolute value of neutrino mass mj can be obtained in the model, and their sum can satisfy the upper bound of the cosmological measurement with ∑j|mj|<0.12 eV. The effective Majorana neutrino mass for neutrinoless double-beta decay is below the current upper limit and is obtained as 〈mββ〉=(0.34,2.3)×10−2 eV. In addition, the doubly charged Higgs H±± decaying to μ±τ± final states can be induced from a dimension-6 operator and is not suppressed, and its branching ratio is compatible with the H±±→W±W± decay when the vacuum expectation value of Higgs triplet is O(0.01) GeV.

Published in: Nuclear Physics B 940 (2019) 292-311
Published by: Elsevier
DOI: 10.1016/j.nuclphysb.2019.01.016
License: CC-BY-3.0

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