Neutrino masses from an A4 symmetry in holographic composite Higgs models
Neutrino masses from an A4 symmetry in holographic composite Higgs models
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DOI：
10.1007/jhep08(2010)127
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发表时间：
2010-01
影响因子：
5.4
通讯作者：
F. Águila;A. Carmona;J. Santiago
中科院分区：
文献类型：
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作者：
F. Águila;A. Carmona;J. Santiago
我们证明了具有离散A4对称性的全息复合Higgs模型是可以建立的，它自然地预言了分级带电轻子质量和近似的三重极大轻子混合，并具有正确的中微子质量尺度和特征现象。它们还满足电弱精密测试、轻子味破坏和轻子混合在大范围参数空间中的电流约束。在我们的模型中出现了两个现象学相关的特征。首先，对轻子汤川耦合的额外抑制使得τ轻子比从其质量天真地预期的更复杂。因此，新的轻轻子共振，质量低至几百GeV，与τ的大耦合和非常典型的对撞机现象，是很有可能的。其次，离散对称性A4与模型结构一起提供了双层风味保护，允许保持树水平介导的过程低于目前的实验限制。然而，违反轻子味的单圈过程，如μ→ eγ，可能在未来的实验中观察到。
We show that holographic composite Higgs Models with a discrete A 4 symmetry can be built, which naturally predict hierarchical charged lepton masses and an approximate tri-bimaximal lepton mixing with the correct scale of neutrino masses and a characteristic phenomenology. They also satisfy current constraints from electroweak precision tests, lepton flavor violation and lepton mixing in a large region of parameter space. Two features arise in our model phenomenologically relevant. First, an extra suppression on the lepton Yukawa couplings makes the τ lepton more composite than naively expected from its mass. As a consequence new light leptonic resonances, with masses as low as few hundreds of GeV, large couplings to τ and a very characteristic collider phenomenology, are quite likely. Second, the discrete symmetry A 4 together with the model structure provide a double-layer of flavor protection that allows to keep tree-level mediated processes below present experimental limits. One-loop processes violating lepton flavor, like μ→ eγ, may be however observable at future experiments.