Weak basis transformations and texture zeros in the leptonic sector

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.     

The breaking of flavor democracy in the quark sector

The democracy of quark flavors is a well-motivated flavor symmetry,but it must be properly broken in order to explain the observed quark mass spectrum and flavor mixing pattern.We reconstruct the texture of flavor democracy breaking and evaluate its strength in a novel way,by assuming a parallelism between the Q = +2/3 and Q =-1/3 quark sectors and using a nontrivial parametrization of the flavor mixing matrix.Some phenomenological implications of such democratic quark mass matrices,including their variations in the hierarchy basis and their evolution from the electroweak scale to a super-high energy scale,are also discussed.     

Optical and phonon properties of Sm-doped α-Bi2O3 micro rods

A simple, low-cost, post-black etching process atop the random pyramidal emitter has been proposed and investigated. The multi-scale texture is achieved by combining nanoporous layer formed by the post-black etching with micron-scale pyramid texture. Compared to the pre-black etched Si solar cells, our experiments clearly show the advantage of post-black etched texturing: it enables high blue response and improved conversion efficiency. As a result, the enhancement of 7.1 mA/cm² on the short-circuit current density and improvement of 31 % in the conversion efficiency have been reached.     

Search for heavy Majorana neutrinos at future lepton colliders

A nonzero neutrino mass may be a sign of new physics beyond the standard model (SM). To explain the small neutrino mass, we can extend the SM using right-handed Majorana neutrinos in a low-scale seesaw mechanism, and the CP violation effect can be induced due to the CP phase in the interference of heavy Majorana neutrinos. The existence of heavy Majorana neutrinos may lead to lepton number violation processes, which can be used to search for the signals of heavy Majorana neutrinos. In this paper, we focus on the CP violation effect related to two generations of heavy Majorana neutrinos at \begin{document}$ 15 $\end{document} GeV \begin{document}$ <m_{N_1}< 70 $\end{document} GeV in the pair production of W bosons and rare decays. It is valuable to investigate Majorana neutrino production signals and the related CP violation effects in rare W boson decays at future lepton colliders.     

CP non-violation in neutral K-meson decay: A non-standard explanation

A recently presented concept, where, in the framework of parametrized relativistic quantum field theory, antiparticles are described consistently with negative frequencies, but positive energy density, is used to analyse the decay of neutralK-mesons, where the experimental results usually are interpreted as an evidence forCP-violation. In the theory presented the charge conjugation is antilinear, as in original Dirac theory, and theCPT-transformation is unitary. The Hamiltonian is indefinite, and changes sign under theCPT-transformation, since positive and negative eigenvalues are interchanged. As a result the eigenstates of the Hamiltonian are notCPT-eigenstates. The interference of positive and negative frequencies leads to a mixing ofCPT-eigenstates, as is observed in experiment. The study of a simple model system shows that the proposed mechanism of dynamical mixing offers an explanation for the experiments on theK ⁰– ⁰-meson system, with respect to both the observed mixing of eigenstates and the observed difference in the number of CP-violating events in the decays of the longer and shorter living neutralK-mesonsK _L andK _S . No symmetry violation of the theory needs be assumed.     

What information can be obtained by RHEED applied on polycrystalline films?

In this paper, an analysis of reflection high-energy electron diffraction (RHEED) performed on polycrystalline films is presented. It is shown that it is possible to obtain qualitative and quantitative information about the crystallography of the deposit. Two series of test samples were used: (i) glass substrates recovered by Fe grains with a (200) fiber-like texture normal or inclined with respect to the surface normal, and (ii) the same films but with a (110) texture. These samples exhibit characteristic RHEED patterns. Using a simple model, it is possible to determine: (i) the texture of the film, (ii) the average angle of the texture axis with respect to the surface normal, and (iii) the angular width of the distribution of this angle about its average value.     

Solar Neutrino Problem in Seesaw Model

A specific texture for the Dirac and Majorana mass matrices in the seesaw model leading to a pair of almost degenerate neutrinos is discussed. This texture can be obtained by imposing a global U(1) symmetry. This model could solve the solar neutrino problem through the MSW mechanism and offer the hot component of the dark matter of the universe which requires Σm_vi = 7 eV.     

The difference between perceived video quality and objective video quality

Abstract  

We select 93 video sequences encoded/decoded by Microsoft MPEG-4 software to classify them into six different content characteristics by the cluster analysis and the discriminant analysis in this study. We compare the peak signal noise ratio (PSNR) of objective video quality evaluation with the mean opinion score of subjective quality evaluation to understand their difference by varying different bit rate. We find that the acceptable satisfaction of user perceived quality for different motion and texture characteristics is significantly different in varying the bit rates. For the low motion and simple texture characteristic (Type 1) and the low motion and complex texture characteristic (Type 4), when the bit rate is 2,000 kbps, the tolerable discarded ratio is allowed to 44% and 49%, and the PSNR is 41.7 dB and 41.0 dB, subjects could perceive the acceptable satisfaction of video quality. For the middle motion and simple texture characteristic (Type 2) and the high motion and simple texture characteristic (Type 3), when the bit rate needs around 3,000 kbps, the tolerable discarded ratio must be controlled below 12% and 34%, and the PSNR is 45.2 dB and 41.7 dB, subjects could perceive the acceptable satisfaction of video quality. For the middle motion and complex texture characteristic (Type 5) and the high motion and complex texture characteristic (Type 6), when the bit rate is 6,000 kbps, the tolerable discarded ratio is allowed to 14%, and the PSNR is 43.2 dB and 42.9 dB, subjects could perceive the acceptable satisfaction of video quality.     

CP symmetry and its violation in fundamental interactions

The concept of discrete symmetries in classical and quantum physics is reviewed. An account is given ofCP violation observed in theK-meson system and of other experiments whereCP symmetry has been tested. The present theoretical ideas onCP violation within the standard model, and problems needing extension of the model are described. Finally, ideas and experimental approaches toCP violation beyond the standard model are reviewed in brief.     

Thermal stability and the magnetization process in CoCrPt–SiO2 perpendicular recording media

The correspondence between the crystallographic texture and intergranular exchange coupling interactions, with the switching mechanism and the thermal response of the magnetization in CoCrPt–SiO₂ perpendicular recording media was investigated. Virgin hysteresis and isothermal remanence magnetization measurements both showed a three-stage process, which was interpreted to indicate that the Stoner–Wohlfarth coherent reversal mode is the dominant switching mechanism irrespective of the texture. For media samples with similar degree of texture, improvement in exchange decoupling of the media grains caused an increase in the onset field for the virgin magnetization process. The thermal decay of the magnetization, evaluated via the field-dependent viscosity coefficient peaked near the nucleation field, and the peak value showed a strong dependence on the strength of the exchange coupling interactions. A model establishing the role of the texture and exchange interactions in perpendicular recording media is put forth.     

Texture zeros for the Standard Model quark mass matrices

A way of counting free parameters in the quark mass matrices of the standard model, including the constraints coming from weak basis transformations, is presented; this allows one to understand the exact physical meaning of the parallel and non-parallel texture zeros which appear in some “ansätze” of the 3×3 quark mass matrices, including the CP violation phenomena in the analysis; it is shown why the six texture zeros are ruled out. Finally, a five texture zeros “ansatz” which properly copes with all experimental constrains, including the angles of the unitary triangle, is presented.     

Possibility of extracting the weak phase 7 from Λb→ Λ0 decays

We explore the possibility of extracting the weak phase γ from pure tree decays Λ_b→ Λ(ie687_01) in a model independent way. We find the CP violating phase γ can be determined cleanly without any hadronic uncertainties. Furthermore, these decays are free from the penguin pollution and neither tagging nor time dependent studies are required for the extraction.     

SUSY CP problem in gauge mediation model

SUSY CP problem in the gauge mediation supersymmetry breaking model is reconsidered. We pay particular attention to two sources of CP violating phases whose effects were not seriously studied before; one is the effect of the breaking of the GUT relation among the gaugino masses due to the field responsible for the GUT symmetry breaking, and the other is the supergravity effect on the supersymmetry breaking parameters, in particular, on the bi-linear supersymmetry breaking Higgs mass term. We show that both of them can induce too large electric dipole moments of electron, neutron, and so on, to be consistent with the experimental bounds.     

A computer programme for the evaluation of Mössbauer data

A high speed Mössbauer fitting programme of general applicability is described. Its main features are the use of transmission integral procedures, full Hamiltonian diagnonalisation for arbitrary spins, magnetic field distribution analysis to the first order, single or polycrystalline intensity calculation for arbitrary (mixed) transitions, and the option to include Goldanskii-Karyagin or texture effects. The programme is designed to maintain a simple logical structure as seen by the user.     

Neutrino masses and lepton-flavor-violating τ decays in the supersymmetric left-right model

In the supersymmetric left-right model,the light neutrino masses are given by the Type-II seesaw mechanism.A duality property of this mechanism indicates that there exist eight possible Higgs triplet Yukawa couplings which result in the same neutrino ma6s matrix.In this paper,we work out the one-loop renormalization group equations for the effective neutrino mass matrix in the supersymmetric left-right model.The stability of the Type-II seesaw scenario is briefly discussed.We also study the lepton-flavor-violating processes (τ→μγ and τ→eγ)by using the reconstructed Higgs triplet Yukawa couplings.     

微光夜视仪分辨力客观测量方法研究

利用灰度 梯度共生矩阵模型对微光夜视仪分辨力测量图像的纹理特征进行了分析 ,通过对大量图像的 5个纹理特征参数的计算 ,结果表明 ,这些参数能对微光夜视仪分辨力测量图像的纹理特征作出有效的客观评价 ,此计算结果与人眼的观察结果具有较好的一致性。     

On the correlation between microstructure and magnetic losses in electrical steel

The magnetic properties of electrical steel such as magnetization curves, magnetization behavior and specific magnetic losses are related to the microstructure and the texture of the steel. A quantitative model, which describes the effect of microstructure and texture and their interplay on the magnetic losses P, is still missing. Based on experimental data for nonoriented electrical steels and FeSi-samples with high (Si, Al)-content, a more general formula is proposed for the dependence of P, at a given value of magnetic induction B, as a function of the mean value of the grain size d of the material and of the intensities of the relevant magnetic texture components.     

Neutrino masses and lepton-flavor-violating τ decays in the supersymmetric left-right model

In the supersymmetric left-right model, the light neutrino masses are given by the Type-Ⅱ seesaw mechanism. A duality property of this mechanism indicates that there exist eight possible Higgs triplet Yukawa couplings which result in the same neutrino mass matrix. In this paper, we work out the one-loop renormalization group equations for the effective neutrino mass matrix in the supersymmetric left-right model. The stability of the Type-Ⅱ seesaw scenario is briefly discussed. We also study the lepton-flavor-violating processes (τ→ μγ and τ→eγ) by using the reconstructed Higgs triplet Yukawa couplings.     

Single Chargino Production with R-Parity Lepton Number Violation in Photon-Photon Collisions

We examine the process γγ→ x+ γ^- at photon-photon collider in the minimal supersymmetric standard model with R-parity violation,where all the one-loop diagrams are considered.We mainly discuss the effects of bilinear breaking terms,and conclude that their contributions may be important compared with trilinear terms.Our results show that the events of this process could be detectable at photon-photon colliders,if the values of the parameters are favorable.