11,360 research outputs found

    On the Potential of Leptonic Minimal Flavour Violation

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    Minimal Flavour Violation can be realized in several ways in the lepton sector due to the possibility of Majorana neutrino mass terms. We derive the scalar potential for the fields whose background values are the Yukawa couplings, for the simplest See-Saw model with just two right-handed neutrinos, and explore its minima. The Majorana character plays a distinctive role: the minimum of the potential allows for large mixing angles -in contrast to the simplest quark case- and predicts a maximal Majorana phase. This points in turn to a strong correlation between neutrino mass hierarchy and mixing pattern.Comment: 6 pages; version published on Physics Letters

    Study of thermal protection requirements for a lifting body entry vehicle suitable for near-earth missions Final report

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    Reentry and abort trajectory analyses, and thermal protection requirements for lifting body entry vehicle

    Revisiting Minimal Lepton Flavour Violation in the Light of Leptonic CP Violation

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    The Minimal Lepton Flavour Violation (MLFV) framework is discussed after the recent indication for CP violation in the leptonic sector. Among the three distinct versions of MLFV, the one with degenerate right-handed neutrinos will be disfavoured, if this indication is confirmed. The predictions for leptonic radiative rare decays and muon conversion in nuclei are analysed, identifying strategies to disentangle the different MLFV scenarios. The claim that the present anomalies in the semi-leptonic BB-meson decays can be explained within the MLFV context is critically re-examined concluding that such an explanation is not compatible with the present bounds from purely leptonic processes.Comment: 36 pages, 4 figures. V2: References added; version accepted for publication on JHE

    El programa de mejora genética de Pinus pinaster en Galicia

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    El pino marítimo es una de las especies más importantes del sector forestal gallego. Fruto de esta importancia, desde los años 80 se lleva a cabo un programa de mejora cuyo fin último es el abastecimiento de semilla de alta calidad genética pasa su uso en repoblación. En este trabajo se revisan las actuaciones realizadas al respecto tanto en la zona costera como en el interior de Galicia. Se describe el dispositivo experimental del programa, los objetivos y la estrategia de mejora, los resultados más relevantes alcanzados hasta la fecha, así como la planificación de las actuaciones futuras. Aunque el programa se centra en caracteres clásicos como la productividad y la rectitud del fuste, se discuten también los resultados obtenidos y las posibilidades de mejora de otros caracteres de interés como la resistencia a patologías y plagas, la eficiencia nutricional o la calidad de madera._____________________________________Maritime pine is one the most important forest-tree species in Galicia. A breeding program was started in the 80’s with the aim to provide genetic improved seed to be use in reforestation. In the present paper we review all the activities done to date, both in the coastal and interior area of Galicia, describing the experimental device, the breeding objectives and breeding strategy, presenting the main results achieved, and advancing further activities of the program. Although the breeding program was focused on classical traits such productivity and stem straightness, results and breeding possibilities of other traits such as pest and disease resistance, nutritional efficiency and wood quality are also discussed

    External Validation of Voter Turnout Models by Concealed Parameter Recovery

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    We conduct a model validation analysis of several behavioral models of voter turnout, using laboratory data. We call our method of model validation concealed parameter recovery, where estimation of a model is done under a veil of ignorance about some of the experimentally controlled parameters — in this case voting costs. We use quantal response equilibrium as the underlying, common structure for estimation, and estimate models of instrumental voting, altruistic voting, expressive voting, and ethical voting. All the models except the ethical model recover the concealed parameters reasonably well. We also report the results of a counterfactual analysis based on the recovered parameters, to compare the policy implications of the different models about the cost of a subsidy to increase turnout

    Bimaximal Neutrino Mixing with Discrete Flavour Symmetries

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    In view of the fact that the data on neutrino mixing are still compatible with a situation where Bimaximal mixing is valid in first approximation and it is then corrected by terms of order of the Cabibbo angle, we present examples where these properties are naturally realized. The models are supersymmetric in 4-dimensions and based on the discrete non-Abelian flavour symmetry S4.Comment: 8 pages, 1 figure; contribution prepared for DISCRETE'10 - Symposium on Prospects in the Physics of Discrete Symmetrie

    Direct Gyrokinetic Comparison of Pedestal Transport in JET with Carbon and ITER-Like Walls

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    This paper compares the gyrokinetic instabilities and transport in two representative JET pedestals, one (pulse 78697) from the JET configuration with a carbon wall (C) and another (pulse 92432) from after the installation of JET's ITER-like Wall (ILW). The discharges were selected for a comparison of JET-ILW and JET-C discharges with good confinement at high current (3 MA, corresponding also to low ρ\rho_*) and retain the distinguishing features of JET-C and JET-ILW, notably, decreased pedestal top temperature for JET-ILW. A comparison of the profiles and heating power reveals a stark qualitative difference between the discharges: the JET-ILW pulse (92432) requires twice the heating power, at a gas rate of 1.9×1022e/s1.9 \times 10^{22}e/s, to sustain roughly half the temperature gradient of the JET-C pulse (78697), operated at zero gas rate. This points to heat transport as a central component of the dynamics limiting the JET-ILW pedestal and reinforces the following emerging JET-ILW pedestal transport paradigm, which is proposed for further examination by both theory and experiment. ILW conditions modify the density pedestal in ways that decrease the normalized pedestal density gradient a/Lna/L_n, often via an outward shift of the density pedestal. This is attributable to some combination of direct metal wall effects and the need for increased fueling to mitigate tungsten contamination. The modification to the density profile increases η=Ln/LT\eta = L_n/L_T , thereby producing more robust ion temperature gradient (ITG) and electron temperature gradient driven instability. The decreased pedestal gradients for JET-ILW (92432) also result in a strongly reduced E×BE \times B shear rate, further enhancing the ion scale turbulence. Collectively, these effects limit the pedestal temperature and demand more heating power to achieve good pedestal performance
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