1,875 research outputs found

    Summary of Golden Measurements at a ν\nu-Factory

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    The precision and discovery potential of a neutrino factory based on muon storage rings is summarized. For three-family neutrino oscillations, we analyze how to measure or severely constraint the angle θ13\theta_{13}, CP violation, MSW effects and the sign of the atmospheric mass difference Δm232\Delta m^2_{23}. The appearance of ``wrong-sign muons'' at three reference baselines is considered: 732 km, 3500 km and 7332 km. We exploit the dependence of the signal on the neutrino energy, and include as well realistic background estimations and detection efficiencies. The optimal baseline turns out to be OO(3000 km).Comment: 7 pages, Latex2e, 5 eps figures, use package espfi

    A Novel Generic Framework for Track Fitting in Complex Detector Systems

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    This paper presents a novel framework for track fitting which is usable in a wide range of experiments, independent of the specific event topology, detector setup, or magnetic field arrangement. This goal is achieved through a completely modular design. Fitting algorithms are implemented as interchangeable modules. At present, the framework contains a validated Kalman filter. Track parameterizations and the routines required to extrapolate the track parameters and their covariance matrices through the experiment are also implemented as interchangeable modules. Different track parameterizations and extrapolation routines can be used simultaneously for fitting of the same physical track. Representations of detector hits are the third modular ingredient to the framework. The hit dimensionality and orientation of planar tracking detectors are not restricted. Tracking information from detectors which do not measure the passage of particles in a fixed physical detector plane, e.g. drift chambers or TPCs, is used without any simplifications. The concept is implemented in a light-weight C++ library called GENFIT, which is available as free software

    Golden measurements at a neutrino factory

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    The precision and discovery potential of a neutrino factory based on muon storage rings is studied. For three-family neutrino oscillations, we analyse how to measure or severely constraint the angle θ13\theta_{13}, CP violation, MSW effects and the sign of the atmospheric mass difference Δm232\Delta m^2_{23}. We present a simple analytical formula for the oscillation probabilities in matter, with all neutrino mass differences non-vanishing, which clarifies the subtleties involved in disentangling the unknown parameters. The appearance of ``wrong-sign muons'' at three reference baselines is considered: 732 km, 3500 km, and 7332 km. We exploit the dependence of the signal on the neutrino energy, and include as well realistic background estimations and detection efficiencies. The optimal baseline turns out to be O(3000{\cal O}(3000 km). Analyses combining the information from different baselines are also presented.Comment: 45 pages, Latex2e, 24 figures using epsfig.sty. An incorrect statement and a few misprints have been corrected. Results and conclusions are unchange

    Determining Neutrino Mass Hierarchy by Precision Measurements in Electron and Muon Neutrino Disappearance Experiments

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    Recently a new method for determining the neutrino mass hierarchy by comparing the effective values of the atmospheric \Delta m^2 measured in the electron neutrino disappearance channel, \Delta m^2(ee), with the one measured in the muon neutrino disappearance channel, \Delta m^2(\mu \mu), was proposed. If \Delta m^2(ee) is larger (smaller) than \Delta m^2(\mu \mu) the hierarchy is of the normal (inverted) type. We re-examine this proposition in the light of two very high precision measurements: \Delta m^2(\mu \mu) that may be accomplished by the phase II of the Tokai-to-Kamioka (T2K) experiment, for example, and \Delta m^2(ee) that can be envisaged using the novel Mossbauer enhanced resonant \bar\nu_e absorption technique. Under optimistic assumptions for the systematic uncertainties of both measurements, we estimate the parameter region of (\theta_13, \delta) in which the mass hierarchy can be determined. If \theta_13 is relatively large, sin^2 2\theta_13 \gsim 0.05, and both of \Delta m^2(ee) and \Delta m^2(\mu \mu) can be measured with the precision of \sim 0.5 % it is possible to determine the neutrino mass hierarchy at > 95% CL for 0.3 \pi \lsim \delta \lsim 1.7 \pi for the current best fit values of all the other oscillation parameters.Comment: 12 pages, 6 postscript figure

    Madera en altura, estado del arte

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    This article is focused on analysing the current situation of timber high-rise construction. It begins with a historical review from the traditional Pagodas (up to 63 m tall) to visions of the future that rises to 350 m. It states the technical development that has led mass timber to today’s engineered products and its researches. It displays timber’s behaviour to fire and its properties as a structural material compared to others more commonly used in high-rise construction. It proves to be as mechanically competitive as concrete or high strength steel. Different strategies can be used against horizontal forces to obtain maximum slenderness. However, its main advantage, from an ecological point of view, is its capacity to absorb CO2, which, along its high degree of prefabrication, makes it a sustainable alternative with an increasing acceptance.El objetivo es mostrar el panorama actual de la edificación en altura con madera. Comienza con una revisión histórica desde las pagodas orientales (hasta 63m de altura) hasta las visiones de futuro (350m). Se muestra el desarrollo tecnológico que ha llevado la madera maciza hasta los productos industrializados actuales y las investigaciones en desarrollo. Se expone su comportamiento ante el fuego y las propiedades como material estructural en comparación con los materiales estructurales más utilizados para la edificación en altura: mecánicamente es tan competitivo como hormigones o aceros de alta resistencia. Ante acciones horizontales hay varias estrategias y se obtienen las esbelteces máximas alcanzables en altura. Su principal ventaja, desde el punto de vista ecológico, es su capacidad de absorber CO2, lo que, junto con el alto nivel de prefabricación, lo convierte en una alternativa sostenible cada vez con mayor aceptació

    Toward CP-even Neutrino Beam

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    The best method of measuring CP violating effect in neutrino oscillation experiments is to construct and use a neutrino beam made of an ideal mixture of νˉe\bar{\nu}_e and νe\nu_e of monochromatic lines. The conceptual design of such a beam is described, together with how to measure the CP-odd quantity. We propose to exploit an accelerated unstable hydrogen-like heavy ion in a storage ring, whose decay has both electron capture and bound beta decay with a comparable fraction.Comment: 6 pages, 2 figures, Published versio

    Exact and Approximate Formulas for Neutrino Mixing and Oscillations with Non-Standard Interactions

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    We present, both exactly and approximately, a complete set of mappings between the vacuum (or fundamental) leptonic mixing parameters and the effective ones in matter with non-standard neutrino interaction (NSI) effects included. Within the three-flavor neutrino framework and a constant matter density profile, a full set of sum rules is established, which enables us to reconstruct the moduli of the effective leptonic mixing matrix elements, in terms of the vacuum mixing parameters in order to reproduce the neutrino oscillation probabilities for future long-baseline experiments. Very compact, but quite accurate, approximate mappings are obtained based on series expansions in the neutrino mass hierarchy parameter \eta \equiv \Delta m^2_{21}/\Delta m^2_{31}, the vacuum leptonic mixing parameter s_{13} \equiv \sin\theta_{13}, and the NSI parameters \epsilon_{\alpha\beta}. A detailed numerical analysis about how the NSIs affect the smallest leptonic mixing angle \theta_{13}, the deviation of the leptonic mixing angle \theta_{23} from its maximal mixing value, and the transition probabilities useful for future experiments are performed using our analytical results.Comment: 29 pages, 8 figures, final version published in J. High Energy Phy

    Drop-in analysis of an internal heat exchanger in a vapour compression system using R1234ze(E) and R450A as alternatives for R134a

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    The IHX (internal heat exchanger) is introduced in some refrigeration systems in order to achieve higher energy performances. Results obtained vary greatly depending on the refrigerant used and working conditions. This paper describes a drop-in analysis of IHX effects on the performance of a vapour compression system using R1234ze(E) and R450A (R134a/R1234ze(E) commercial mixture) as R134a low-GWP replacements. The tests were carried out in a completely monitored vapour compression system varying the condensing and evaporating temperature, with and without a counter-current flow tube-in-tube IHX. Because the cooling capacity rises and the power consumption remains similar, the conclusion is that the IHX has a positive influence on the energy efficiency for all refrigerants tested. The COP (coefficient of performance) gain using R1234ze(E) is the highest observed (overcomes the R134a COP for the same conditions). The R1234ze(E) and R450A discharge temperature increments are lower than those of R134a so does not reach dangerous values and the IHX pressure drops are also below than that of R134a.The authors thankfully acknowledge "Ministerio de Educacion, Cultura y Deporte - Gobierno de Espana" (Grant number FPU12/02841) for supporting this work through "Becas y Contratos de Formacion de Profesorado Universitario del Programa Nacional de Formacion de Recursos Humanos de Investigacion del ejercicio 2012".Mota Babiloni, A.; Navarro Esbrí, J.; Barragán Cervera, Á.; Moles, F.; Peris, B. (2015). Drop-in analysis of an internal heat exchanger in a vapour compression system using R1234ze(E) and R450A as alternatives for R134a. Energy. 90:1636-1644. https://doi.org/10.1016/j.energy.2015.06.133S163616449

    Ion transport and selectivity in nanopores with spatially inhomogeneous fixed charge distributions

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    Polymeric nanopores with fixed charges show ionic selectivity when immersed in aqueous electrolyte solutions. The understanding of the electrical interaction between these charges and the mobile ions confined in the inside nanopore solution is the key issue in the design of potential applications. The authors have theoretically described the effects that spatially inhomogeneous fixed charge distributions exert on the ionic transport and selectivity properties of the nanopore. A comprehensive set of one-dimensional distributions including the skin, core, cluster, and asymmetric cases are analyzed on the basis of the Nernst-Planck equations. Current-voltage curves, nanopore potentials, and transport numbers are calculated for the above distributions and compared with those obtained for a homogeneously charged nanopore with the same average fixed charge concentration. The authors have discussed if an appropriate design of the spatial fixed charge inhomogeneity can lead to an enhancement of the transport and selectivity with respect to the homogeneous nanopore case. Finally, they have compared the theoretical predictions with relevant experimental [email protected] [email protected]
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