346 research outputs found

    Canonical Constraints on Leptonic Cp Violation using UHCR neutrino fluxes

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    It is shown that one can in principle constrain the CP-violating parameter delta from measurements of four independant |V_{ij}|^2, or three of them and a ratio, in the leptonic sector. To quantify our approach, using unitarity, we derive simple expressions in terms of four independant |V_{ij}|^2 for cos(delta) and an expression for sin^2(delta) from J^2. Thus, depending on the values of |V_{ij}| and their accuracy, we can set meaningful limits on |delta|. To illustrate numerically, if |V_{u1}|^2 is close to 0.1 with a 10% precision, and if |V_{e3}^2 is larger than 0.005 and for values of |V_{e2}|^2 and |V_{u3}|^2 that stay within +-0.1 of the current experimental data leads to a bound pi/2 < |delta| < pi. Alternatively, a certain combination of parameters with values of |V_{e3}|^2 larger than 0.01 leads to a closed bound of 73 < |delta| < 103. In general, we find that it is better to use |V_{u1}|^2 or |V_{t1}|^2 as the fourth independant |V_{ij}|^2 and that over most of the parameter space, delta is least sensitive to |V_{e3}|^2. With just three independant measurements (solar, atmospheric and reactor) it is impossible to set limits on the CP phase. In this respect, we study the use of ultra high energy cosmic (UHCR) neutrino fluxes as the additional fourth information. We find that within the SM, neutrino fluxes of all three flavours will be very similar but that pushing current neutrino data to their extreme values still allowed, ratios of cosmic neutrino fluxes can differ by up to 20%; such large discrepancies could imply negligibly small CP-violation. We also study a non radiative neutrino decay model and find that the neutrino fluxes can differ by a factor of up to 3 within this model and that an accuracy of 10% on the neutrino fluxes is sufficient to set interestin limits on delta.Comment: 8 pages, 2 figures, 5 table

    Constrained MSSM and the electric dipole moment of the neutron

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    We study the constraints on the CP-violating soft-breaking phases in the minimal supersymmetric standard model using the limits on the chromoelectric dipole moment of the strange quark extracted from the neutron EDM experiment. Our investigation shows that the phase mediated by the gluino exchange diagram has to be very small, ϕ≀810−4\phi\leq 8 10^{-4}, for the common supersymmetric mass of the order of 100 GeV. Then, solving the renormalization group equations analytically by iterations, we calculate the electric dipole moment of the neutron in the MSSM with CP-conserving soft-breaking parameters for the case of three and four generations. For the three-generation case we resolve the apparent discrepancies between order-of-magnitude estimates and numerical calculations existing in the literature. In this case the EDM of the neutron does not exceed 10−32ecm10^{-32} e cm. For the four-generation case we show that there is a significant enhancement which renders the EDM of the neutron at a measurable level of 10−26ecm10^{-26}e cm.Comment: 18 pages, LaTex, 2 fig

    Live video streaming over packet networks and wireless channels

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    The transmission of live video over noisy channels requires very low end-to-end delay. Although automatic repeat request ensures lossless transmission, its usefulness to live video streaming is restricted to short connections because of the unbounded retransmission latency. An alternative is to use forward error correction (FEC). Since finding an optimal error protection strategy can be time expensive, FEC systems are commonly designed for the worst case condition of the channel, which limits the end-to-end performance. We study the suitability of two scalable FEC-based systems to the transmission of live video over packet networks. The first one uses Reed-Solomon codes and is appropriate for the Internet. The second one uses a product channel code and is appropriate for wireless channels. We show how fast and robust transmission can be achieved by exploiting a parametric model for the distortion-rate curve of the source coder and by using fast joint source-channel allocation algorithms. Experimental results for the 3D set partitioning in hierarchical tree video coder show that the systems have good reconstruction quality even in severe channel conditions. Finally, we compare the performance of the systems to the state-of-the-art for video transmission over the Internet. 1

    Patterns in the Fermion Mixing Matrix, a bottom-up approach

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    We first obtain the most general and compact parametrization of the unitary transformation diagonalizing any 3 by 3 hermitian matrix H, as a function of its elements and eigenvalues. We then study a special class of fermion mass matrices, defined by the requirement that all of the diagonalizing unitary matrices (in the up, down, charged lepton and neutrino sectors) contain at least one mixing angle much smaller than the other two. Our new parametrization allows us to quickly extract information on the patterns and predictions emerging from this scheme. In particular we find that the phase difference between two elements of the two mass matrices (of the sector in question) controls the generic size of one of the observable fermion mixing angles: i.e. just fixing that particular phase difference will "predict" the generic value of one of the mixing angles, irrespective of the value of anything else.Comment: 29 pages, 3 figures, references added, to appear in PR

    Experiments on joint source-channel fractal image coding with unequal error protection

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    We propose a joint source-channel coding system for fractal image compression. We allocate the available total bit rate between the source code and a range of error-correcting codes using a Lagrange multiplier optimization technique. The principle of the proposed unequal error protection strategy is to partition the information bits into sensitivity classes and to assign one code from a range of error-correcting codes to each sensitivity class in a nearly optimal way. Experimental results show that joint source-channel coding with fractal image compression is feasible, leads to ef"cient protection strategies, and outperforms previous works in this "eld that only covered channel coding with a "xed source rate

    Pulmonary Embolism Revealing Idiopathic Membranous Glomerulonephritis

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    We describe a case of a 55-year-old man who presented with pulmonary embolism and who was found to have nephrotic syndrome due to idiopathic membranous nephropathy. There are no other signs of nephrotic syndrome such as edema

    Thymic hyperplasia in a patient with Grave's disease

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    Hyperplastic changes of the thymus may be found in patients with Graves' disease. However, this rarely presents as an anterior mediastinal mass, particularly among adults. In this report, we describe a 46-year old woman with Graves' disease and thymic hyperplasia

    Association myĂ©lome multiple – maladie de Kaposi: Ă  propos d’un cas

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    L'association Kaposi–myĂ©lome multiple est extrĂȘmement rare. Nous rapportons, le cas d'un patient ĂągĂ© de 76 ans suivi dans notre formation pour un myĂ©lome Ă  immunoglobuline A kappa stade III-B selon Durie et Salmon. Ceci a Ă©tĂ© associĂ© Ă  des lĂ©sions cutanĂ©es dont la biopsie cutanĂ©e Ă©tait en faveur d’une maladie de Kaposi. La sĂ©rologie de l’herpĂšs virus humain de type 8 (HHV8) est revenue positive. Une radiothĂ©rapie sur les lĂ©sions Ă©tait refusĂ©e par le patient. L'Ă©volution Ă©tait marquĂ©e par une altĂ©ration de l'Ă©tat gĂ©nĂ©ral. Le patient ayant refusĂ© la radiothĂ©rapie et toute prise en charge thĂ©rapeutique est dĂ©cĂ©dĂ©e deux mois plus tard. Nous rapportons, Ă  notre connaissance, le 18Ăšme cas mondial de maladie de Kaposi associĂ©e Ă  un Kahler chez un patient HHV8 positif. C'est une association exceptionnelle rendant probable le rĂŽle pathogĂ©nique de HHV8 dans le dĂ©veloppement du myĂ©lome

    SUSY, the Third Generation and the LHC

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    We develop a bottom-up approach to studying SUSY with light stops and sbottoms, but with other squarks and sleptons heavy and beyond reach of the LHC. We discuss the range of squark, gaugino and Higgsino masses for which the electroweak scale is radiatively stable over the "little hierarchy" below ~ 10 TeV. We review and expand on indirect constraints on this scenario, in particular from flavor and CP tests. We emphasize that in this context, R-parity violation is very well motivated. The phenomenological differences between Majorana and Dirac gauginos are also discussed. Finally, we focus on the light subsystem of stops, sbottom and neutralino with R-parity, in order to probe the current collider bounds. We find that 1/fb LHC bounds are mild and large parts of the motivated parameter space remain open, while the 10/fb data can be much more decisive.Comment: 42 pages, 8 figures, 1 table. V2: minor corrections, references adde
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