共查询到20条相似文献,搜索用时 15 毫秒
1.
We show that non-Hermitian and nearest-neighbor-interacting perturbations to the Fritzsch textures of lepton and quark mass matrices can make both of them fit current experimental data very well. In particular, we obtain θ23?45° for the atmospheric neutrino mixing angle and predict θ13?3° to 6° for the smallest neutrino mixing angle when the perturbations in the lepton sector are at the 20% level. The same level of perturbations is required in the quark sector, where the Jarlskog invariant of CP violation is about 3.7×10−5. In comparison, the strength of leptonic CP violation is possible to reach about 1.5×10−2 in neutrino oscillations. 相似文献
2.
The solar and baseline neutrino oscillation data suggest bimaximal neutrino mixing among the first two generations, and trimaximal mixing between all three neutrino flavors. It has been conjectured that this indicates the existence of an underlying symmetry for the leptonic fermion mass textures. The experimentally measured quantities, however, are associated to the latter indirectly and in a rather complicated way through the mixing matrices of the charged leptons and neutrinos. Motivated by these facts, we derive exact analytical expressions which directly link the charged lepton and neutrino mass and mixing parameters to measured quantities and obtain constraints on the parameter space. We discuss deviations from Tri-Bi mixing matrices and present minimal extensions of the Harrison, Perkins and Scott matrices capable of interpreting all neutrino data. 相似文献
3.
In the context of the minimal seesaw framework, we discuss the implications of Dirac and Majorana mass matrices in which two properties coexist, namely, equalities among matrix elements and texture zeros. Among the large number of general possibilities, only 12 patterns are found to be consistent with the global neutrino oscillation data at the level of the most minimal number of free parameters. The predictions of the allowed textures for mass hierarchy, θ13 and effective mass governing neutrino-less double beta decay are discussed. We also explore the possibility of having non-zero CP violation for each allowed solution. We find that only one allowed solution can accommodate both low and high energy CP violation. We discuss the prediction of this solution for leptogenesis and explore the correlation, between leptogenesis and low energy CP violation. 相似文献
4.
B. Mukhopadhyaya S. Raychudhuri K. Agashe B. Allanach D. Bailin B. Brahmachari U. Chattopadhyay D. Choudhury P. Das Amitava Datta Anindya Datta A. Djouadi A. Giri K. Huitu A. Kundu U. Mahanta S. Moretti B. Mukhopadhyaya J. C. Pati A. K. Ray A. Raychaudhuri S. Raychaudhuri P. Roy N. Singh R. Vaidya 《Pramana》2003,60(2):395-399
5.
We present the symmetry realization of the phenomenologically viable Frampton-Glashow-Marfatia (FGM) two zero texture neutrino mass matrices in the flavor basis within the framework of the type (I+II) seesaw mechanism natural to SO(10) grand unification. A small Abelian cyclic symmetry group Z3 is used to realize these textures except for class C for which the symmetry is enlarged to Z4. The scalar sector is restricted to the Standard Model (SM) Higgs doublet to suppress the flavor changing neutral currents. Other scalar fields used for symmetry realization are at the most two scalar triplets and, in some cases, a complex scalar singlet. Symmetry realization of one zero textures has, also, been presented. 相似文献
6.
Eligio Lisi 《Progress in Particle and Nuclear Physics》2010,64(2):171-177
Established results on neutrino mass, mixing and flavor change (as of 2009) are briefly reviewed. Status and prospects of unknown neutrino properties (smallest mixing angle, Dirac/Majorana nature, absolute masses and their hierarchy) are also discussed. 相似文献
7.
S. Morisi E. Peinado 《Physics letters. [Part B]》2011,701(4):451-457
We propose a realization of the so-called bimodal/schizophrenic model proposed recently. We assume S4, the permutation group of four objects as flavor symmetry giving tri-bimaximal lepton mixing at leading order. In these models the second massive neutrino state is assumed quasi-Dirac and the remaining neutrinos are Majorana states. In the case of inverse mass hierarchy, the lower bound on the neutrinoless double beta decay parameter mee is about two times that of the usual lower bound, within the range of sensitivity of the next generation of experiments. 相似文献
8.
For the purpose of deriving the observed nearly tribimaximal neutrino mixing, a possible yukawaon model in the quark sector is investigated. Five observable quantities (2 up-quark mass ratios and 3 neutrino mixing parameters sin22θatm, tan2θsolar and |U13|) are excellently fitted by two parameters (one in the up-quark sector and another one in the right-handed Majorana neutrino sector). 相似文献
9.
Hisakazu Minakata 《Progress in Particle and Nuclear Physics》2010,64(2):216-218
After making brief comments on the Kamioka-Korea two-detector setting, I delivered a pedagogical seminar on perturbation theory of neutrino oscillations with and without nonstandard interactions. I also described a general property of neutrino flavor transformation of such a system which includes useful relationships between S matrix elements and a phase reduction theorem. 相似文献
10.
Integrating out a heavy field gives rise to effective Lagrangian containing higher-dimensional operators. In the context of Type-I seesaw mechanism, integrating out the heavy right-handed neutrino field leads to unique dimension-five operator which gives the tree level neutrino mass term. Apart from these there are dimension-six operators that can have important implications. A linear combination of two such operators gives rise to the non-unitarity in the lepton mixing matrix, UPMNS. In this paper, we discuss the origin of non-unitarity at the high scale and its evolution through renormalization group running. 相似文献
11.
Anjan S Joshipura 《Pramana》2000,54(1):119-132
The observed deficits in the solar and atmospheric neutrino fluxes along with the accelerator results on neutrino oscillations
significantly constrain possible mass and mixing patterns among neutrinos. We discuss possible patterns emerging from the
experimental results and review theoretical attempts to understand them. 相似文献
12.
It is known that the charged lepton masses obey to high precision an interesting empirical relation (Koide relation). In turn, the light neutrino masses cannot obey such a relation. We note that if neutrinos acquire their mass via the seesaw mechanism, the empirical mass relation could hold for the masses in the Dirac and/or heavy Majorana mass matrix. Examples for the phenomenological consequences are provided. We furthermore modify the mass relation for light neutrino masses including their Majorana phases, and show that it can be fulfilled in this case as well, with interesting predictions for neutrinoless double beta decay. 相似文献
13.
G.C. Branco D. Emmanuel-Costa R. Gonzlez Felipe H. Serdio 《Physics letters. [Part B]》2009,670(4-5):340-349
We investigate the physical meaning of some of the texture zeros which appear in most of the ansatzes on leptonic masses and their mixing. It is shown that starting from arbitrary lepton mass matrices and making suitable weak basis transformations one can obtain some of these sets of zeros, which therefore have no physical content. We then analyse four-zero texture ansatzes where the charged lepton and neutrino mass matrices have the same structure. The four texture zeros cannot be obtained simultaneously through weak basis transformations, so these ansatzes do have physical content. We show that they can be separated into four classes and study the physical implications of each class. 相似文献
14.
We calculate finite quantum corrections to the tribimaximal neutrino mixing pattern VTB in three generic classes of neutrino mass models. We show that three flavor mixing angles can all depart from their tree-level results described by VTB, among which θ12 is most sensitive to such quantum effects, and the Dirac CP-violating phase can radiatively arise from two Majorana CP-violating phases. This theoretical scheme offers a new way to understand why θ13 is naturally small and how three CP-violating phases are presumably correlated. 相似文献
15.
H. Fritzsch 《Progress in Particle and Nuclear Physics》2010,64(2):313-314
We study a model for the mass matrices of the leptons, based on texture zero elements. We are able to relate the mass eigenvalues of the charged leptons and of the neutrinos to the mixing angles, and can predict the masses of the neutrinos. We find a normal hierarchy—the masses are 0.005 eV, 0.01 eV and 0.05 eV. Predictions for the double beta decay and the reactor neutrino experiments are made. 相似文献
16.
Werner Rodejohann 《Progress in Particle and Nuclear Physics》2010,64(2):321-323
Scaling is a highly predictive and fully reconstructible Ansatz for the structure of the neutrino Majorana mass matrix, which can be obtained in many models and scenarios. We summarize the phenomenology of scaling and discuss in particular its interesting aspects in the framework of the see-saw mechanism. 相似文献
17.
We investigate baryogenesis in the ν MSM, which is the Minimal Standard Model (MSM) extended by three right-handed neutrinos with Majorana masses smaller than the weak scale. In this model the baryon asymmetry of the universe (BAU) is generated via flavour oscillation between right-handed neutrinos. We consider the case when BAU is solely originated from the CP violation in the mixing matrix of active neutrinos. We perform analytical and numerical estimations of the yield of BAU, and show how BAU depends on mixing angles and CP violating phases. It is found that the asymmetry in the inverted hierarchy for neutrino masses receives a suppression factor of about 4% comparing with the normal hierarchy case. It is, however, pointed out that, when θ13=0 and θ23=π/4, baryogenesis in the normal hierarchy becomes ineffective, and hence the inverted hierarchy case becomes significant to account for the present BAU. 相似文献
18.
19.
We have studied the bulk viscosity of strange quark matter in the density dependent quark mass model (DDQM) and compared results
with calculations done earlier in the MIT bag model where u, d masses were neglected and first order interactions were taken into account. We find that at low temperatures and high relative
perturbations, the bulk viscosity is higher by 2 to 3 orders of magnitude while at low perturbations the enhancement is by
1–2 order of magnitude as compared to earlier results. Also the damping time is 2–3 orders of magnitude lower implying that
the star reaches stability much earlier than in MIT bag model calculations. 相似文献
20.
Single β-decay of 187Re and double β-decay are discussed for probing absolute masses of neutrinos. It is shown that 187Re decay is dominated by p-wave emission of the electron over s-wave. Double β-decay nuclear matrix elements relevant to the neutrino mass mechanism are discussed in the view point of nuclear structure and the underlying NN interaction. 相似文献