θ_(13) and the Higgs Mass from High Scale Supersymmetry

In the framework in which supersymmetry is used for understanding fermion masses rather than stabilizing the electroweak scale, we elaborate on the phenomenological analysis for the neutrino physics. A relatively large sinθ13 0.13 is naturally obtained. The model further predicts vanishingly small CP violation in neutrino oscillations. While the high scale supersymmetry generically results in a Higgs mass of about 141 GeV, our model reduces this mass to 126 GeV via introducing SU(2)L triplet fields which make the electroweak vacuum metastable (with a safe lifetime) and also contribute to neutrino masses.     

Is the magic texture of Majorana neutrinos immanent in Dirac nature?

Magic textures are successful candidates of the correct texture for Majorana neutrinos. In this study, we demonstrate that several types of magic textures of Majorana neutrinos are approximately immanent in the flavor mass matrix of Dirac neutrinos. In addition, the normal mass ordering of Dirac neutrino masses is slightly preferable to inverted mass ordering in the context of magic textures.     

Quantum Mechanics of Neutrino Oscillations

We present a simple but general treatment of neutrino oscillations in the framework of quantum mechanics, using plane waves and intuitive wave packet principles when necessary. We attempt to clarify some confusing statements that have recently appeared in the literature.     

中微子几何混合模型与轻子和重子数产生

在这一报告中将报告我和BABU教授合作的在hep-ph/0507217一文中有关中微子混合研究结果. 目前中微子实验数据所决定的混合角可归结为几何混合状况:sin²θ₁₂=1/3,sin²θ₂₃=1/2, 和sin²θ₁₃=0. 我们在这一工作中建立了能实现这一几何混合的可重整化模型. 模型以非阿贝尔非连续群A₄为描述中微子不同代混合的对称性. 这类模型对中微子质量有很强的限制. 而且能很自然地由轻子数破坏产生重子不对称的实验观测值. 很有趣的是这类模型中出现在轻子不守恒和无中微子双beta衰变中的相位是一样的.     

Bounds on neutrino mixing with exotic singlet neutrinos

We examine the effects of mixing induced non-diagonal light-heavy neutrino weak neutral currents on the amplitude for the process (with a=e, μ or τ). By imposing constraint that the amplitude should not exceed the perturbative unitarity limit at high energy , we obtain bounds on light-heavy neutrino mixing parameter sin² where is the mixing angle. In the case of one heavy neutrino (mass mξ) or mass degenerate heavy neutrinos, for Λ=1 TeV, no bound is obtained for mξ<0.50 TeV. However, sin² ≤3.8 × 10⁻⁶ for mξ=5 TeV and sin ≤6.0 × 10⁻⁸ for mξ=10 TeV. For Λ=∞, no constraint is obtained for mξ<0.99 TeV and sin² ≤3.8 × 10⁻² (for mξ=5 TeV) and sin² ≤9.6 × 10⁻³ (for mξ=10 TeV).     

Phenomenology of Friedberg-Lee Texture in Left-Right Symmetric Model

We consider that the Higgs triplet Yukawa coupling takes the Friedberg-Lee texture, and the Higgs doublet Yukawa coupling simply identifies with the diagonal Yutawa coupling of charged lepton in the context of left-right symmetric model. In this scenario, the phenomenology, including effective neutrino masses, mixings, and thermal flavor-dependent leptogenesis and lepton flavor violation decays are studied. We investigate the combined constrain of the parameters in this scenario and test its consistency with present data.     

Maximal atmospheric neutrino mixing from texture zeros and quasi-degenerate neutrino masses

It is well known that, in the basis where the charged-lepton mass matrix is diagonal, there are seven cases of two texture zeros in Majorana neutrino mass matrices that are compatible with all experimental data. We show that two of these cases, namely B₃ and B₄ in the classification of Frampton, Glashow and Marfatia, are special in the sense that they automatically lead to near-maximal atmospheric neutrino mixing in the limit of a quasi-degenerate neutrino mass spectrum. This property holds true irrespective of the values of the solar and reactor mixing angles because, for these two cases, in the limit of a quasi-degenerate spectrum, the second and third row of the lepton mixing matrix are, up to signs, approximately complex-conjugate to each other. Moreover, in the same limit the aforementioned cases also develop a maximal CP-violating CKM-type phase, provided the reactor mixing angle is not too small.     

Oscillations Do Not Distinguish Between Massive and Tachyonic Neutrinos

It is shown that the hypothesis of tachyonic neutrinos leads to the same oscillations effect as if they were usual massive particles. Therefore, the experimental evidence of neutrino oscillations does not distinguish between massive and tachyonic neutrinos. Thus, in view of the fact that the results of the direct neutrino mass measurements are not decisive, the question about the nature of neutrinos remains still open.     

A Model of Fermion Masses and Flavor Mixings with Family Symmetry SU(3)U(1)

The family symmetry SU(3)U(1) is proposed to solve flavor problems about fermion masses and flavor mixings.It is breaking is implemented by some flavon fields at the high-energy scale.In addition a discrete group Z 2 is introduced to generate tiny neutrino masses,which is broken by a real singlet scalar field at the middle-energy scale.The low-energy effective theory is elegantly obtained after all of super-heavy fermions are integrated out and decoupling.All the fermion mass matrices are regularly characterized by four fundamental matrices and thirteen parameters.The model can perfectly fit and account for all the current experimental data about the fermion masses and flavor mixings,in particular,it finely predicts the first generation quark masses and the values of θ l 13 and J l CP in neutrino physics.All of the results are promising to be tested in the future experiments.     

Search for Cold Dark Matter and Solar Neutrinos with GENIUS and GENIUS-TF

The new project GENIUS will cover a wide range of the parameter space of predictions of SUSY for neutralinos as cold dark matter. Further it has the potential to be a real-time detector for low-energy (pp and ⁷Be) solar neutrinos. A GENIUS Test Facility has been funded and will come into operation by early 2003.     

First Evidence for Neutrinoless Double Beta Decay

Double beta decay is indispensable to solve the question of the neutrino mass matrix together with oscillation experiments. Recent analysis of the most sensitive experiment since nine years—the HEIDELBERG-MOSCOW experiment in Gran-Sasso—yields a first indication for the neutrinoless decay mode. This result is the first evidence for lepton number violation and proves the neutrino to be a Majorana particle. We give the present status of the analysis in this report. It excludes several of the neutrino mass scenarios allowed from present neutrino oscillation experiments—only degenerate scenarios and those with inverse mass hierarchy survive. This result allows neutrinos to still play an important role as dark matter in the Universe. To improve the accuracy of the present result, considerably enlarged experiments are required, such as GENIUS. A GENIUS Test Facility has been funded and will come into operation by early 2003.     

后中微子振荡发现的实验进展与展望

2015年诺贝尔物理学奖授予了发现中微子振荡也就是中微子有质量的实验。这个发现是至今为止,粒子物理标准模型——这一得到广泛实验验证的理论中唯一指明存在新物理的明显证据。文章将介绍中微子振荡发现以后主要的中微子实验物理目标、采用的探测技术、实验状况及其未来展望。     

Distinguishable RGE Running Effects Between Dirac Neutrinos and Majorana Neutrinos with Vanishing Majorana CP-Violating Phases

In a novel parametrization of neutrino mixing and in the approximation of т-lepton dominance, we show that the one-loop renormalization-group equations (RGEs) of Dirac neutrinos are different from those of Majorana neutrinos even if two Majorana CP-violating phases vanish. As the latter can keep vanishing from the electroweak scale to the typical seesaw scale, it makes sense to distinguish between the RGE running effects of neutrino mixing parameters in Dirac and Majorana cases. The differences are found to be quite large in the minimal supersymmetric standard model with sizable tanβ, provided the masses of three neutrinos are nearly degenerate or have an inverted hierarchy.