Leptogenesis in the two right-handed neutrino model revisited
Leptogenesis in the two right-handed neutrino model revisited
复制标题
DOI：
10.1103/physrevd.86.023516
复制
发表时间：
2011-07
影响因子：
5
通讯作者：
S. Antusch;S. Antusch;P. Bari;D. A. Jones;S. King
中科院分区：
文献类型：
--
作者：
S. Antusch;S. Antusch;P. Bari;D. A. Jones;S. King
我们重新审视具有两个右手 (RH) 中微子的最小非超对称 I 型跷跷板机制中的轻子发生，包括风味效应，并允许 RH 中微子 ${N}_{1}$ 和 ${N}_{2}$ 做出贡献，而不仅仅是迄今为止考虑的最轻的 RH 中微子 ${N}_{1}$。通过根据正交矩阵 $R$ 的单个复角 $z$ 对参数空间进行扫描，对于一系列轻子混合参数，我们发现在 $z\ensuremath{\sim}\ifmmode\pm\else\textpm\fi{}\ensuremath{\pi}/2$ 周围的区域中，对于正常质量层次结构的情况，${N}_{2}$ 的贡献可以主导对轻子发生的贡献，从而允许这些区域中最轻的 RH 中微子质量将减少约一个数量级，降至 ${M}_{1}\ensuremath{\sim}1.3\ifmmode\times\else\texttimes\fi{}{10}^{11}\text{ }\text{ }\mathrm{GeV}$，初始 ${N}_{2}$ 丰度消失，数值结果得到解析支持估计。我们表明 $z\ensuremath{\sim}\ifmmode\pm\else\textpm\fi{}\ensuremath{\pi}/2$ 周围的区域对应于光顺序优势，因此本文的新结果可能与统一模型构建相关。
We revisit leptogenesis in the minimal nonsupersymmetric type I seesaw mechanism with two right-handed (RH) neutrinos, including flavor effects and allowing both RH neutrinos ${N}_{1}$ and ${N}_{2}$ to contribute, rather than just the lightest RH neutrino ${N}_{1}$ that has hitherto been considered. By performing scans over parameter space in terms of the single complex angle $z$ of the orthogonal matrix $R$, for a range of leptonic mixing parameters, we find that in regions around $z\ensuremath{\sim}\ifmmode\pm\else\textpm\fi{}\ensuremath{\pi}/2$, for the case of a normal mass hierarchy, the ${N}_{2}$ contribution can dominate the contribution to leptogenesis, allowing the lightest RH neutrino mass to be decreased by about an order of magnitude in these regions, down to ${M}_{1}\ensuremath{\sim}1.3\ifmmode\times\else\texttimes\fi{}{10}^{11}\text{ }\text{ }\mathrm{GeV}$ for vanishing initial ${N}_{2}$-abundance, with the numerical results supported by analytic estimates. We show that the regions around $z\ensuremath{\sim}\ifmmode\pm\else\textpm\fi{}\ensuremath{\pi}/2$ correspond to light sequential dominance, so the new results in this paper may be relevant to unified model building.