Tatsuo Kobayashi

An introduction to non-Abelian discrete symmetries for particle physicists

Introduction.- Basics of Finite Groups.- Subgroups and Decompositions of Multiplets.- Anomalies.- Non-Abelian Discrete Symmetry in Quark/Lepton Flavor Models.- Useful Theorems.- Representations of S4 in Different Bases.- Representations of A4 in Different Bases.- Representations of A5 in Different Bases.- Representations of T1 in Different Bases.- Other Smaller Groups.- References.

Polynomial inflation models after BICEP2

Large field inflation models are favored by the recent BICEP2 that has detected gravitational wave modes generated during inflation. We study general large field inflation models for which the potential contains (constant) quadratic and quartic terms of inflaton field. We show, in this framework, those inflation models can generate the fluctuation with the tensor-to-scalar ratio of 0.2 as well as the scalar spectral index of 0.96; those are very close to the center value of the tensor-to-scalar ratio reported by BICEP2 as well as Planck. Finally, we briefly discuss the particle physics model building of inflation.

Z N twisted orbifold models with magnetic flux

A bstractWe propose new backgrounds of extra dimensions to lead to four-dimensional chiral models with three generations of matter fermions, that is T2/ZN twisted orbifolds with magnetic fluxes. We consider gauge theory on six-dimensional space-time, which contains the T2/ZN orbifold with magnetic flux, Scherk-Schwarz phases and Wilson line phases. We classify all the possible Scherk-Schwarz and Wilson line phases on T2/ZN orbifolds with magnetic fluxes. The behavior of zero modes is studied. We derive the number of zero modes for each eigenvalue of the ZN twist, showing explicitly examples of wave functions. We also investigate Kaluza-Klein mode functions and mass spectra.

Phenomenological aspects of 10D SYM theory with magnetized extra dimensions

Abstract We present a particle physics model based on a ten-dimensional (10D) super Yang–Mills (SYM) theory compactified on magnetized tori preserving four-dimensional N = 1 supersymmetry. The low-energy spectrum contains the minimal supersymmetric standard model with hierarchical Yukawa couplings caused by a wavefunction localization of the chiral matter fields due to the existence of magnetic fluxes, allowing a semi-realistic pattern of the quark and the lepton masses and mixings. We show supersymmetric flavor structures at low energies induced by a moduli-mediated and an anomaly-mediated supersymmetry breaking.

Classification of three-generation models on magnetized orbifolds

Abstract We classify the combinations of parameters which lead three generations of quarks and leptons in the framework of magnetized twisted orbifolds on T 2 / Z 2 , T 2 / Z 3 , T 2 / Z 4 and T 2 / Z 6 with allowing nonzero discretized Wilson line phases and Scherk–Schwarz phases. We also analyze two actual examples with nonzero phases leading to one-pair Higgs and five-pair Higgses and discuss the difference from the results without nonzero phases studied previously. (Note: this article is registered under preprint number: arXiv:1501.02787 [hep-ph] .)

Axion monodromy inflation with sinusoidal corrections

We study the axion monodromy inflation with a non-perturbatively generated sinusoidal term. The potential form is a mixture between the natural inflation and the axion monodromy inflation potentials. The sinusoidal term is subdominant in the potential, but leaves significant effects on the resultant fluctuation generated during inflation. A larger tensor-to-scalar ratio can be obtained in our model. We study two scenarios, single inflation scenario and the double inflation scenario. In the first scenario, the axion monodromy inflation with a sufficient number of e-fold generates a larger tensor-to-scalar ratio about

CKM matrix and flavor symmetries

0.1 - 0.15

Superfield description of 10D SYM theory with magnetized extra dimensions

but also a tiny running of spectral index. In the second scenario of double inflation, axion monodromy inflation is its first stage and, we assume another inflation follows. In this case, our model can realize a larger tensor-to-scalar ratio and a large negative running of spectral index simultaneously.

Axion monodromy inflation with multi-natural modulations

Following the way proposed recently by Hernandez and Smirnov, we seek possible residual symmetries in the quark sector with a focus on the von Dyck groups. We begin with two extreme cases in which both

Shifted orbifold models with magnetic flux

theta_{13}