Conditions of naturalness and fine-tunings for type-I seesaw mechanism with four-zero texture
Conditions of naturalness and fine-tunings for type-I seesaw mechanism with four-zero texture
复制标题
四零纹理I型跷跷板机构的自然度及微调条件
DOI：
10.1093/ptep/ptac054
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发表时间：
2022
影响因子：
3.5
通讯作者：
Masaki J.S. Yang
中科院分区：
文献类型：
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作者：
Narita Emi;Honda Mitsuru;Nakata Motoki;Yoshida Maiko; Hayashi Nobuhiko;Masaki J.S. Yang
在本文中，我们寻找轻中微子质量矩阵ν不是四零纹理I型跷跷板机制大抵消结果的条件。对于中微子的汤川矩阵 Yν 和重马约拉纳质量矩阵 MR，这些条件写为：我们称它们为对齐条件，因为它们对齐三个中微子质量矩阵的某些行或列。如果这些条件不成立，则 mν 中的大混合是由于取消了多项而进行微调的结果。那么从自然性的角度来看，它们是需要的。他们解释了四零纹理的跷跷板不变性，并对中微子的味道结构进行了粗略的限制。在这些条件下，Yν必须具有级联层次结构。对于MR，12子矩阵具有与Yν和mν类似的层次结构。然而，23 个子矩阵具有瀑布层次结构，无需进行任何微调。因此，Yν 和 MR 很可能具有性质不同的风味结构。此外，由于条件限制了矩阵元素的 CP 相位，因此它们意味着中微子扇区中存在通用的广义 CP 对称性。
In this paper, we search for conditions under which the mass matrix of light neutrinosmνis not a result of large cancellations for the type-I seesaw mechanism with four-zero texture. For the Yukawa matrix of neutrinosYνand heavy Majorana mass matrixMR, these conditions are written as. We call themalignmentconditions because they align certain rows or columns of the three neutrino mass matrices. If these conditions do not hold, the large mixing inmνis a result of fine-tuning due to the cancellation of several terms. Then they are required from the viewpoint of naturalness. They give an explanation of the seesaw invariance of four-zero texture, and place rough restrictions on flavor structures of neutrinos. Under these conditions,Yνmust have a cascade hierarchy. ForMR, the 12 submatrix has a similar hierarchy toYνandmν. However, the 23 submatrix has a waterfall hierarchy without some fine-tuning. Therefore, it is likely thatYνandMRhave qualitatively different flavor structures. Furthermore, since the conditions restrict CP phases of the matrix elements, they imply the existence of a universal generalized CP symmetry in the neutrino sector.