Modular symmetry in the SMEFT
Modular symmetry in the SMEFT
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DOI：
10.1103/physrevd.105.055022
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发表时间：
2021-12
影响因子：
5
通讯作者：
Tatsuo C. Kobayashi;Hajime Otsuka;M. Tanimoto;Kei Yamamoto
中科院分区：
文献类型：
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作者：
Tatsuo C. Kobayashi;Hajime Otsuka;M. Tanimoto;Kei Yamamoto
我们研究了模对称标准模型有效场论。我们采用了弦的Angleson耦合结构，即物质场的四点耦合y（4）由物质场的三点耦合y（3）的乘积写成，即，y（4）= y（3）y（3）。在这个框架下，我们讨论了双线性费米子算子和4-费米子算子的味结构，其中出现了全纯和反全纯模形式。具有手征翻转的双线性算符与夸克和轻子的成功质量矩阵有关。在附近的不动点τ = i，ω，i ∞上发现了一些味变跃迁的关系式，这些关系式在将来是可检验的.作为应用，我们讨论了轻子味破坏过程μ → e γ，τ → e γ和τ → μ γ之间的关系。我们预测BR（τ → μ γ）<$BR（τ → e γ）<$BR（μ → e γ），并输入分支比BR（μ → e γ）<4.2 × 10 − 13的当前上限，我们得到BR（τ → μ γ）<1.4 × 10 − 9和BR（τ → e γ）<1.4 × 10 − 11。这些预测与U（2）味对称的预测不同。我们还研究了夸克A4模对称中的变味4夸克算符。因此，最小的味道违反可以通过采取相关的特定参数集的顺序一实现。
We study the modular symmetric standard-model effective field theory. We employ the stringy Ansatz on coupling structure that 4-point couplings y(4) of matter fields are written by a product of 3-point couplings y(3) of matter fields, i.e., y(4) = y(3)y(3). In this framework, we discuss the flavor structure of bilinear fermion operators and 4-fermion operators, where the holomorphic and anti-holomorphic modular forms appear. The bilinear operators with chirality flip are related with the successful mass matrix of quarks and leptons. We find some relations of the flavor changing transition at nearby fixed points τ = i, ω , i∞, which are testable in the future. As an application, we discuss the relations of the lepton flavor violation processes, μ → eγ, τ → eγ and τ → μγ. We predict BR(τ → μγ) ≫ BR(τ → eγ) ≫ BR(μ → eγ), and inputting the current upperbound of the branching ratio BR(μ→ eγ) < 4.2×10−13, we obtain BR(τ → μγ) < 1.4×10−9 and BR(τ → eγ) < 1.4×10−11. These predictions are different from the ones of the U(2) flavor symmetry. We also study the flavor changing 4-quark operators in the A4 modular symmetry of quarks. As a result, the minimal flavor violation could be realized by taking relevant specific parameter sets of order one.