8136589
Deviation from tri-bimaximal mixing and flavor symmetry breaking in a seesaw type A(4) model
Abstract We have studied the contribution of higher order corrections of the flavor symmetry breaking in the A 4 seesaw model with the supersymmetry. Taking account of possible higher dimensional mass operators, we predict the deviation from the tri-bimaximal lepton mixing for both normal hierarchy and inverted hierarchy of neutrino masses. We have found that the value of sin 2 2 θ 23 is larger than 0.96 and the upper bound of sin 2 θ 13 is 0.01. We have also examined the flavor changing neutral current of leptons from the soft SUSY breaking in slepton masses and A-terms within the framework of supergravity theory. Those magnitudes are enough suppressed to be consistent with experimental constraints.
453979
S4 Flavor Model of Quarks and Leptons
We present an S4 flavor model to unify quarks and leptons in the framework of the SU(5) GUT. Three generations of 5-plets in SU(5) are assigned to be 31 of S4 while the first and the second generations of 10-plets in SU(5) are assigned to be 2 of S4 ,a nd the third generation of 10-plet is to be 11 of S4. Right-handed neutrinos are also assigned to be 2 for the first and second generations and 11 for the third generation, respectively. Taking vacuum alignments of relevant gauge singlet scalars, we predict the quark mixing as well as the tri-bimaximal mixing of neutrino flavors. Especially, the Cabbibo angle is predicted to be 15 ◦ in the limit of the vacuum alignment. We can improve the model to predict observed CKM mixing angles.
118633837
Like-Sign Dimuon Asymmetry of B0 Meson and LFV in SU(5) SUSY GUT with S4 Flavor Symmetry
The like-sign dimuon charge asymmetry of the B meson, which was reported in the DO Collaboration, is studied in the SU(5) SUSY GUT model with S4 flavor symmetry. Additional CP violating effects from the squark sector are discussed in Bs- ¯ Bs mixing process. The predicted like-sign charge asymmetry is in the 2σ range of the combined result of DO and CDF measurements. Since the SUSY contributions in the quark sector affect to the lepton sector because of the SU(5) GUT relation, two predictions are given in the leptonic processes: (i) both BR(μ → eγ) and the electron EDM are close to the present upper bound, (ii) the decay ratios of τ decays, τ → μγ and τ → eγ, are related to each other via the Cabibbo angle λc :B R( τ → eγ)/BR(τ → μγ) � λ 2. These are testable at future experiments. Subject Index: 142, 151, 152, 154, 158
120533600
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.
9783573
S4 Flavor Symmetry of Quarks and Leptons in SU(5) GUT
We present an S4 flavor model to unify quarks and leptons in the framework of the SU(5) GUT. Three generations of 5-plets in SU(5) are assigned to 31 of S4, while the first and second generations of 10-plets in SU(5) are assigned to 2 of S4, and the third generation of 10-plets is assigned to 11 of S4. Right-handed neutrinos are also assigned to 2 for the first and second generations and to 11 for the third generation. By considering the vacuum alignments of relevant gauge singlet scalars, we predict the quark mixing as well as the tribimaximal mixing of neutrino flavors. In particular, the Cabbibo angle is predicted to be 15 ◦ in the limit of the vacuum alignment. We can improve the model to predict observed CKM mixing angles as well as the nonvanishing Ue3 of the neutrino flavor mixing. Subject Index: 140, 154
116955892
Realisability of SUSY discrete flavour symmetry in our universe
We study the realisation of supersymmetric discrete flavour symmetry models to the thermal history of our universe. We focus on the evolution of the pseudo moduli field among the flavons by taking into account finite temperature corrections. We show that the pseudo moduli flavon dominates the energy density of our universe and this domination makes crucially difficult to realise the flavour symmetry models in our universe. We also discuss possible extensions of the supersymmetric discrete flavour symmetry models which can ensure the consistency of the models with the thermal history of our universe. Finally, we show an extension to realise the thermal inflation by the flavon domination.
121264816
Electroweak corrections to muon pair production in electron-positron annihilation at high energy
Abstract The lowest-order radiative corrections to the reaction e + + e − → μ + + μ − are analyzed in the standard SU(2) × U(1) electroweak theory. The virtual corrections are calculated in the on-shell renormalization scheme. The masses of the recently discovered Z-boson and W-boson are used to fix the weak coupling constants. The decay width of the Z-boson is also taken into account. By including the cross section of hard photon emission, various kinds of distribution are obtained both analytically and numerically. The magnitude of the effective axial vector coupling is confirmed to be quite different from that previously taken in the calculations within QED. This difference, which is due to the genuine electroweak corrections, reaches about 10% in angular distribution at the energy around the Z-boson mass, even if the reasonable effect of a hard photon is included.
12942853
Calculation of strongly-coupled rotational bands in terms of the tilted axis cranking model
Abstract Recently observed strongly-coupled rotational bands associated with the ν[505] 11 2 − quasiparticle state are studied by means of a microscopic tilted axis cranking (TAC) model. The results of calculation for the routhians and the B (M1)/ B (E2) ratios are investigated in the light of other existing models, i.e., the strong-coupling model and the conventional cranking model. It is demonstrated that only the TAC model can successfully reproduce these two observables at the same time. The reason of the success is clarified by making connections between these models.
121954152
The role of spin-orbit potential in nuclear prolate-shape dominance
Abstract It is confirmed, in terms of the Woods–Saxon–Strutinsky method, that the spin–orbit potential plays a decisive role in the predominance of prolate deformation, which has been a long standing problem in nuclear physics. It is originated from the combined effects of the spin–orbit coupling and the diffused surface of the potential, in agreement with the previous work based on a more schematic Nilsson–Strutinsky method. The degree of prolate-shape dominance exhibits an oscillatory behavior with respect to the strength of spin–orbit potential and, the prolate-shape dominance is realized at the proper strength of the spin–orbit potential together with the standard surface diffuseness; this oscillatory behavior disappears in case of small diffuseness corresponding to ellipsoidal cavity. The calculated energy differences between oblate and prolate minima in this Letter are consistent with those of our extensive self-consistent calculations of the Hartree–Fock + BCS method with the Skyrme interaction.
119827880
Parity violation in helium and cesium and the effect of electron-electron interaction
Abstract We investigate the parity violating effect in helium and cesium atoms due to the exchange of a Z 0 -meson between atomic electrons. It is found that this effect is negligible for both atoms in comparison with the contribution from the electron-nucleus interactions, if we take the neutral-current coupling between electrons as predicted by the SU (2) × U (1) theory and sin 2 θ W ≈ 0.3.
12101981
Microscopic Study of Wobbling Motions in Hf and Lu Nuclei
One of the most striking findings in the recent high-spin spectroscopy is the discovery of one-phonon, and possibly double-phonon, excitation of the nuclear wobbling rotational bands. In this talk, we first review the properties of observed wobbling motions, and discuss the failure and success of the possible interpretation in terms of the simple rotor model. Then, we further present results of our microscopic study in Hf and Lu nuclei by means of the theoretical framework, the cranked mean-field and the random phase approximation.