arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1910.03460hep-ph
收藏

模 $S_4$ 和 $A_4$ 对称性及其固定点:轻子混合的新预测示例

Modular $S_4$ and $A_4$ Symmetries and Their Fixed Points: New Predictive Examples of Lepton Mixing

University of Science and Technology of China(中国科学技术大学);University of Southampton(南安普顿大学)

Gui-Jun Ding, Stephen F. King, Xiang-Gan Liu, Jun-Nan Lu

AI总结:

本文研究了 $S_4$ 和 $A_4$ 对称性的固定点,应用于轻子混合,发现三种现象学上可行的模型,其中轻子混合呈现三极最大化 TM1 模式。

摘要:

在中子模型的模对称性方法中,风味对称性作为模对称性的有限子群 $Γ_N$ 出现,通过模场 $τ$ 的真空期望值(VEV)被打破。如果模场 $τ$ 的VEV取某些特殊值,$Γ_N$ 的残余子群会被保留。我们推导出在基本域中不变于模变换的固定点 $τ_S=i$,$τ_{ST}=(-1+i\sqrt{3})/2$,$τ_{TS}=(1+i\sqrt{3})/2$,$τ_T=i\infty$。然后我们将这些固定点推广到上半复平面上的 $τ_f=γτ_S$,$γτ_{ST}$,$γτ_{TS}$ 和 $γτ_{T}$,并显示只需考虑 $γ\inΓ_{N}$。聚焦于 $N=4$ 的层级,对应于风味群 $S_4$,我们考虑在这些固定点上到重量6的所有三元模形式。然后我们将结果应用于轻子混合,其中带电轻子部分和每个右手轻子部分有不同的残余子群。在最简情况下,即两个右手轻子的情况下,我们发现三种现象学上可行的情况,其中轻子质量矩阵仅依赖于三个自由参数,且轻子混合取三极最大化 TM1 模式。其中一种情况对应于基于 CSD$(n)$ 的新 Littlest Modular Seesaw,其中 $n=1+\sqrt{6}\approx 3.45$,介于 CSD$(3)$ 和 CSD$(4)$ 之间。最后,我们将结果推广到具有三个右手轻子的例子,也考虑了 $N=3$ 的情况,对应于 $A_4$ 味对称性。

英文摘要:

In the modular symmetry approach to neutrino models, the flavour symmetry emerges as a finite subgroup $Γ_N$ of the modular symmetry, broken by the vacuum expectation value (VEV) of a modulus field $τ$. If the VEV of the modulus $τ$ takes some special value, a residual subgroup of $Γ_N$ would be preserved. We derive the fixed points $τ_S=i$, $τ_{ST}=(-1+i\sqrt{3})/2$, $τ_{TS}=(1+i\sqrt{3})/2$, $τ_T=i\infty$ in the fundamental domain which are invariant under the modular transformations indicated. We then generalise these fixed points to $τ_f=γτ_S$, $γτ_{ST}$, $γτ_{TS}$ and $γτ_{T}$ in the upper half complex plane, and show that it is sufficient to consider $γ\inΓ_{N}$. Focussing on level $N=4$, corresponding to the flavour group $S_4$, we consider all the resulting triplet modular forms at these fixed points up to weight 6. We then apply the results to lepton mixing, with different residual subgroups in the charged lepton sector and each of the right-handed neutrinos sectors. In the minimal case of two right-handed neutrinos, we find three phenomenologically viable cases in which the light neutrino mass matrix only depends on three free parameters, and the lepton mixing takes the trimaximal TM1 pattern for two examples. One of these cases corresponds to a new Littlest Modular Seesaw based on CSD$(n)$ with $n=1+\sqrt{6}\approx 3.45$, intermediate between CSD$(3)$ and CSD$(4)$. Finally, we generalize the results to examples with three right-handed neutrinos, also considering the level $N=3$ case, corresponding to $A_4$ flavour symmetry.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑