Non-vanishing U(e3) and cos 2 theta(23) from a broken Z(2) symmetry
Non-vanishing U(e3) and cos 2 theta(23) from a broken Z(2) symmetry
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DOI：
10.1016/j.nuclphysb.2005.01.049
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发表时间：
2004-08
期刊：
影响因子：
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通讯作者：
W. Grimus;Anjan S.Joshipura;S. Kaneko;L. Lavoura;H. Sawanaka;M. Tanimoto
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文献类型：
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作者：
W. Grimus;Anjan S.Joshipura;S. Kaneko;L. Lavoura;H. Sawanaka;M. Tanimoto
结果表明，中微子质量矩阵的味基产生一个消失的Ue 3下的一类Z2对称性的特点是不变性。在这一类别中的特定Z2也导致最大大气混合角θ23。Z2的破缺可以用两个无量纲量ε和ε′来表征，并对ε，ε′ <$0的影响进行了微扰和数值研究.的诱导值|UE3|很大程度上取决于中微子的质量等级。我们发现|UE3|对于正常质量等级，即使ε，ε′ <$30%，也小于0.07。对于倒置的体量层次结构|UE3|倾向于在0.1左右，但可以大到0.17。在准简并中微子的情况下，|UE3|可能接近实验上限0.2。与此相反，|cos 2 θ23|总是能达到实验上限0.28。我们提出了一个具体的模型，在MSSM的电弱辐射修正的基础上，ε和ε′。在这个模型中，两者|UE3|和|cos 2 θ23|如果中微子是准简并的，则它们的能量密度可能接近各自的实验上限。
It is shown that the neutrino mass matrices in the flavour basis yielding a vanishing Ue3are characterized by invariance under a class of Z2symmetries. A specific Z2in this class also leads to a maximal atmospheric mixing angle θ23. The breaking of that Z2can be parameterized by two dimensionless quantities, ε and ε′; the effects of ε,ε′≠0 are studied perturbatively and numerically. The induced value of |Ue3| strongly depends on the neutrino mass hierarchy. We find that |Ue3| is less than 0.07 for a normal mass hierarchy, even when ε,ε′∼30%. For an inverted mass hierarchy |Ue3| tends to be around 0.1 but can be as large as 0.17. In the case of quasi-degenerate neutrinos, |Ue3| could be close to its experimental upper bound 0.2. In contrast, |cos2θ23| can always reach its experimental upper bound 0.28. We propose a specific model, based on electroweak radiative corrections in the MSSM, for ε and ε′. In that model, both |Ue3| and |cos2θ23|, could be close to their respective experimental upper bounds if neutrinos are quasi-degenerate.