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The flavor structures on magnetized orbifold models and 4D modular symmetric models
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| Title: | The flavor structures on magnetized orbifold models and 4D modular symmetric models |
| Other Titles: | 磁化オービフォールドモデルと4次元モジュラー対称モデルにおけるフレーバー構造 |
| Authors: | 菊地, 渉太 Browse this author |
| Issue Date: | 25-Mar-2024 |
| Publisher: | Hokkaido University |
| Abstract: | We study quark and lepton flavor structures on magnetized T 2/Z2 twisted orbifold model. There are 6,460 number of flavor models but most of them cannot lead to realistic flavor observ-ables because of the difficulties on realizing mass hierarchies and small (large) mixing angles of quarks (lentons). We find that certain zero point patterns of zero-modes of fermions and Higgs fields give the flavor models being able to avoid these difficulties. We classify such flavor models and show numerical example. Also we study (T 2 1 × T 2 2 )/Z(per) 2 permutation model and its Z2 twist orbifolding. Additionally we study Yukawa matrices at three modular symmetric points, τ = i, ω and i∞, where S, ST and T -symmetries remain. We find Yukawa matrices on T 2/Z2 orbifold have a kind of texture structures because of the residual symmetries. Next we study four-dimensional (4D) modular symmetric quark flavor models without fine-tuning. Mass matrices are written in terms of the modular forms. The modular forms become hierarchical as close to the modular symmetric points depending on its residual charges. Ac-tually the residual ZN symmetries with N ≥ 6 can originate the large quark mass hierarchies. Also the products of residual symmetries such as Z3 × Z3 × Z3 have such possibility. First we study the quark flavor model with Γ6 symmetry. We assume the vicinity of the cusp τ = i∞ where residual Z6 symmetry remains. To make our analysis simple we use only Γ6 singlet modular forms. Consequently we find the models realizing the order of the quark mass ratios and the absolute values of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements without fine-tuning. In the same way, we study the quark flavor models with A4 × A4 × A4 symmetry. Then we discuss the CP violation caused by the value of the modulus τ and show numerical example. Results imply the quark flavors including the CP phase require non-universal moduli. Finally we construct the Siegel modular forms. Zero-modes on T 6 at⃗z = 0 are the Siegel modular forms of weight 1/2 for the subgroup of Sp(6, Z). They have several moduli parameters and therefore have the possibility realizing the flavor structures including the CP phases. We study the Siegel modular forms transformed by e∆(96) and show numerical example using the singlet Siegel modular forms. We find one of moduli patameters ω1 works on the large mass hierarchies and ω2 works on the CP violation successfully in our model. |
| Conffering University: | 北海道大学 |
| Degree Report Number: | 甲第15741号 |
| Degree Level: | 博士 |
| Degree Discipline: | 理学 |
| Examination Committee Members: | (主査) 教授 小林 達夫, 教授 鈴木 久男, 准教授 瀬戸 治, 講師 末廣 一彦 |
| Degree Affiliation: | 理学院（宇宙理学専攻） |
| Type: | theses (doctoral) |
| URI: | http://hdl.handle.net/2115/92284 |
| Appears in Collections: | 学位論文 (Theses) > 博士 （理学）
課程博士 (Doctorate by way of Advanced Course) > 理学院(Graduate School of Science)
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