Lepton flavor model with modular A4 symmetry in large volume limit
Lepton flavor model with modular A4 symmetry in large volume limit
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DOI：
10.1016/j.physletb.2020.135956
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发表时间：
2020-09
影响因子：
4.4
通讯作者：
T. Asaka;Yongtae Heo;Takahiro Yoshida
中科院分区：
文献类型：
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作者：
T. Asaka;Yongtae Heo;Takahiro Yoshida
我们认为与额外维紧化有关的模对称性是轻子扇区上的味对称性。特别地，我们提出了一个基于三个右手中微子和一个规范单重态Higgs的模A4对称性的模型，该模型在额外维度的大体积极限（即对于模τ，Im τ→∞）下工作得很好.引入右手中微子，实现了振荡实验中观测到的微小中微子质量的跷跷板机制。单态希格斯粒子的真空期望值给出了右手中微子的马约拉纳质量和希格斯场的μ项。该模型能较好地解释中微子的质量和混合角。我们发现其中一个混合角应该在sin 2 <$θ 23≥ 0.58的范围内。重要的是，在这两个限制区的中微子CP破坏相的预测。一个是狄拉克相是δ CP <$− 0.5 π，马约拉纳相是α 21 <$0和α 31 <$π。另一种是δ CP <$0 + 0.5 π，α 2 1 <$2 π和α 31 <$π。无中微子双β衰变的有效中微子质量为m_eff= 0.037-0.047 eV。这些预测将在未来的中微子实验中得到验证。
We consider the modular symmetry associated with the compactification of extra dimensions as the flavor symmetry on lepton sector. Especially, we propose a model based on the modular A 4 symmetry with three right-handed neutrinos and a gauge singlet Higgs, which works well in the so-called large volume limit of the extra dimensions, ie, Im τ→∞ for a modulus τ. The right-handed neutrinos are introduced to realize the seesaw mechanism for tiny neutrino masses observed in oscillation experiments. The vacuum expectation value of the singlet Higgs gives the Majorana masses for right-handed neutrinos and the μ-term for Higgs fields. The model can explain the observed masses and mixing angles of neutrinos successfully. We find that one of the mixing angles should be in the range sin 2 θ 23≥ 0.58. Importantly, the CP violating phases of neutrinos are predicted in the two restricted regions. One is that the Dirac phase is δ CP≃− 0.5 π and the Majorana phases are α 21≃ 0 and α 31≃ π. The other is δ CP≃+ 0.5 π, α 21≃ 2 π and α 31≃ π. The effective neutrino mass in the neutrinoless double beta decay is found to be m eff= 0.037–0.047 eV. These predictions will be tested in the future neutrino experiments.