6,801 research outputs found

    Analytic Solutions to the RG Equations of the Neutrino Physical Parameters

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    In the case of two generation neutrinos, the energy-scale dependence of the lepton-flavor mixing matrix with Majorana phase can be governed by only one parameter r, which is the ratio between the diagonal elements of neutrino mass matrix. By using this parameter r, we derive the analytic solutions to the renormalization group equations of the physical parameters, which are the mixing angle, Majorana phase, and the ratio of the mass-squared difference to the mass squared of the heaviest neutrino. The energy-scale dependence of the Majorana phase is clarified by using these analytic solutions. The instability of the Majorana phase causes in the same parameter region in which the mixing angle is unstable against quantum corrections.Comment: LaTeX2e, 9 pages, 6 figure

    The effects of Majorana phases in three-generation neutrinos

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    Neutrino-oscillation solutions for the atmospheric neutrino anomaly and the solar neutrino deficit can determine the texture of the neutrino mass matrix according to three types of neutrino mass hierarchies as Type A: m1m2m3m_1^{} \ll m_2^{} \ll m_3^{}, Type B: m1m2m3m_1^{} \sim m_2^{} \gg m_3^{}, and Type C: m1m2m3m_1^{} \sim m_2^{} \sim m_3^{}, where mim_i is the ii-th generation neutrino absolute mass. The relative sign assignments of neutrino masses in each type of mass hierarchies play the crucial roles for the stability against quantum corrections. Actually, two physical Majorana phases in the lepton flavor mixing matrix connect among the relative sign assignments of neutrino masses. Therefore, in this paper we analyze the stability of mixing angles against quantum corrections according to three types of neutrino mass hierarchies (Type A, B, C) and two Majorana phases. Two phases play the crucial roles for the stability of the mixing angles against the quantum corrections.Comment: LaTeX2e, 15 pages, 8 figure

    Energy-Scale Dependence of the Lepton-Flavor-Mixing Matrix

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    We study an energy-scale dependence of the lepton-flavor-mixing matrix in the minimal supersymmetric standard model with the effective dimension-five operators which give the masses of neutrinos. We analyze the renormalization group equations of kappa_{ij}s which are coefficients of these effective operators under the approximation to neglect the corrections of O(\kappa^2). As a consequence, we find that all phases in κ\kappa do not depend on the energy-scale, and that only n_g-1 (n_g: generation number) real independent parameters in the lepton-flavor-mixing matrix depend on the energy-scale.Comment: 6 pages, no figur

    The effect of Majorana phase in degenerate neutrinos

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    There are physical Majorana phases in the lepton flavor mixing matrix when neutrinos are Majorana fermions. In the case of two degenerate neutrinos, the physical Majorana phase plays the crucial role for the stability of the maximal flavor mixing between the second and the third generations against quantum corrections. The physical Majorana phase of π\pi guarantees the maximal mixing to be stable against quantum corrections, while the Majorana phase of zero lets the maximal mixing be spoiled by quantum corrections when neutrino masses are of O(eV). The continuous change of the Majorana phase from π\pi to 0 makes the maximal mixing be spoiled by quantum corrections with O(eV) degenerate neutrino masses. On the other hand, when there is the large mass hierarchy between neutrinos, the maximal flavor mixing is not spoiled by quantum corrections independently of the Majorana phase.Comment: 7 pages, 1 figures, LaTe

    Are lepton flavor mixings in the democratic mass matrix stable against quantum corrections?

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    We investigate whether the lepton flavor mixing angles in the so-called democratic type of mass matrix are stable against quantum corrections or not in the minimal supersymmetric standard model with dimension five operator which induces neutrino mass matrix. By taking simple breaking patterns of S3L×S3RS_3{}_L \times S_3{}_R or O(3)L×O(3)RO(3)_L \times O(3)_R flavor symmetries and the scale where democratic textures are induced as O(1013)O(10^{13}) GeV, we find that the stability of the lepton flavor mixing angles in the democratic type of mass matrix against quantum corrections depends on the solar neutrino solutions. The maximal flavor mixing of the vacuum oscillation solution is spoiled by the quantum corrections in the experimental allowed region of tanβ\tan \beta. The large angle MSW solution is spoiled by the quantum corrections in the region of tanβ>10\tan \beta > 10. The condition of tanβ10\tan \beta \leq 10 is needed in order to obtain the suitable mass squared difference of the small angle MSW solution. These strong constraints must be regarded for the model building of the democratic type of mass matrixComment: 12pages,LaTe

    Goodness-of-Fit Tests for Symmetric Stable Distributions -- Empirical Characteristic Function Approach

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    We consider goodness-of-fit tests of symmetric stable distributions based on weighted integrals of the squared distance between the empirical characteristic function of the standardized data and the characteristic function of the standard symmetric stable distribution with the characteristic exponent α\alpha estimated from the data. We treat α\alpha as an unknown parameter, but for theoretical simplicity we also consider the case that α\alpha is fixed. For estimation of parameters and the standardization of data we use maximum likelihood estimator (MLE) and an equivariant integrated squared error estimator (EISE) which minimizes the weighted integral. We derive the asymptotic covariance function of the characteristic function process with parameters estimated by MLE and EISE. For the case of MLE, the eigenvalues of the covariance function are numerically evaluated and asymptotic distribution of the test statistic is obtained using complex integration. Simulation studies show that the asymptotic distribution of the test statistics is very accurate. We also present a formula of the asymptotic covariance function of the characteristic function process with parameters estimated by an efficient estimator for general distributions

    Holographic Screening Length in a Hot Plasma of Two Sphere

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    We study the screening length of a quark-antiquark pair moving in a hot plasma living in two sphere S2S^2 manifold using AdS/CFT correspondence where the background metric is four dimensional Schwarzschild-AdS black hole. The geodesic solution of the string ends at the boundary is given by a stationary motion in the equatorial plane as such the separation length LL of quark-antiquark pair is parallel to the angular velocity ω\omega. The screening length and the bound energy are computed numerically using Mathematica. We find that the plots are bounded from below by some functions related to the momentum transfer PcP_c of the drag force configuration. We compare the result by computing the screening length in the quark-antiquark reference frame where the gravity dual are "Boost-AdS" and Kerr-AdS black holes. Finding relations of the parameters of both black holes, we argue that the relation between mass parameters MSchM_{Sch} of the Schwarzschild-AdS black hole and MKerrM_{Kerr} of the Kerr-AdS black hole in high temperature is given by MKerr=MSch(1a2l2)3/2M_{Kerr}=M_{Sch}(1-a^2l^2)^{3/2}, where aa is the angular momentum parameter.Comment: Major revision: title changed, adding authors, 13 pages, 8 figures, etc. Accepted for publication in European Physical Journal

    Si/Ge hole-tunneling double-barrier resonant tunneling diodes formed on sputtered flat Ge layers

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    We have demonstrated Si/Ge hole-tunneling double-barrier resonant tunneling diodes (RTDs) formed on flat Ge layers with a relaxation rate of 89% by our proposed method; in this method, the flat Ge layers can be directly formed on highly B-doped Si(001) substrates using our proposed sputter epitaxy method. The RTDs exhibit clear negative differential resistance effects in the static current–voltage (I–V) curves at room temperature. The quantized energy level estimation suggests that resonance peaks that appeared in the I–V curves are attributed to hole tunneling through the first heavy- and light-hole energy levels

    Spectroscopic Observation on the Combustion Characteristics of Japanese Traditional Oil Lamp

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    In this research, spectroscopic measurement has been made to investigate the combustion characteristics of a Japanese traditional oil lamp, called toumyou, that has been used since ancient periods until present. Combustion characteristics, i.e. flame stability and temperature, were analyzed by using a temperature video camera. Spectral emission intensity of hydroxyl (OH) radical (band head of 310 nm) was measured by using a UV-visible spectrometer and visualized by a CCD camera while the brightness was measured using a lux meter. The experimental result showed that the flames of vegetable oils burned were stable and temperatures ranged over about 1000-2500ºC. In addition, the emission intensity of OH radical was successfully detected by the UV-visible spectrometry and visualized by the CCD Camera. The emission intensities of OH radical from flames of coconut oil and palm oil were higher than those of other tested vegetable oils. From measurement using a lux meter, it was obtained that coconut oil gives the brightest flame

    Void-induced cross slip of screw dislocations in fcc copper

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    Pinning interaction between a screw dislocation and a void in fcc copper is investigated by means of molecular dynamics simulation. A screw dislocation bows out to undergo depinning on the original glide plane at low temperatures, where the behavior of the depinning stress is consistent with that obtained by a continuum model. If the temperature is higher than 300 K, the motion of a screw dislocation is no longer restricted to a single glide plane due to cross slip on the void surface. Several depinning mechanisms that involve multiple glide planes are found. In particular, a depinning mechanism that produces an intrinsic prismatic loop is found. We show that these complex depinning mechanisms significantly increase the depinning stress
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