3,459 research outputs found

    Supersymmetric dark matter search via spin-dependent interaction with He3

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    The potentialities of MIMAC-He3, a MIcro-tpc MAtrix of Chambers of Helium 3, for supersymmetric dark matter search are discussed within the framework of effective MSSM models without gaugino mass unification at the GUT scale. A phenomenological study has been done to investigate the sensitivity of the MIMAC-He3 detector to neutralinos (m > 6 GeV/c2) via spin-dependent interaction with He3 as well as its complementarity to direct and indirect detection experiments. Comparison with other direct dark matter searches will be presented in a WIMP model-independent framework.Comment: 13 pages, 5 figure

    MIMAC-He3 : MIcro-tpc MAtrix of Chambers of He3

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    The project of a micro-TPC matrix of chambers of He3 for direct detection of non-baryonic dark matter is outlined. The privileged properties of He3 are highlighted. The double detection (ionization - projection of tracks) will assure the electron-recoil discrimination. The complementarity of MIMAC-He3 for supersymmetric dark matter search with respect to other experiments is illustrated. The modular character of the detector allows to have different gases to get A-dependence. The pressure degreee of freedom gives the possibility to work at high and low pressure. The low pressure regime gives the possibility to get the directionality of the tracks. The first measurements of ionization at very few keVs for He3 in He4 gas are described

    Project of a superfluid He3 detector for direct detection of non-baryonic dark matter : MACHe3

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    MACHe3 (MAtrix of Cells of superfluid Helium 3) is a project of non-baryonic Dark Matter search using superfluid He3 as sensitive medium. Simulations on a high granularity matrix show very good rejection against background events. First results on a prototype cell are very encouraging. Neutron detection has been highlighted as well as cosmic muon detection. A phenomenological study has been done with the DarkSUSY code to investigate complementarity of MACHe3 with existing Dark Matter detectors.Comment: 5 pages, 5 figures, to appear in Proceedings of the 4th Marseille International Cosmology Conferenc

    An analysis method for time ordered data processing of Dark Matter experiments

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    The analysis of the time ordered data of Dark Matter experiments is becoming more and more challenging with the increase of sensitivity in the ongoing and forthcoming projects. Combined with the well-known level of background events, this leads to a rather high level of pile-up in the data. Ionization, scintillation as well as bolometric signals present common features in their acquisition timeline: low frequency baselines, random gaussian noise, parasitic noise and signal characterized by well-defined peaks. In particular, in the case of long-lasting signals such as bolometric ones, the pile-up of events may lead to an inaccurate reconstruction of the physical signal (misidentification as well as fake events). We present a general method to detect and extract signals in noisy data with a high pile-up rate and qe show that events from few keV to hundreds of keV can be reconstructed in time ordered data presenting a high pile-up rate. This method is based on an iterative detection and fitting procedure combined with prior wavelet-based denoising of the data and baseline subtraction. {We have tested this method on simulated data of the MACHe3 prototype experiment and shown that the iterative fitting procedure allows us to recover the lowest energy events, of the order of a few keV, in the presence of background signals from a few to hundreds of keV. Finally we applied this method to the recent MACHe3 data to successfully measure the spectrum of conversion electrons from Co57 source and also the spectrum of the background cosmic muons

    Mimac-He3, a Project for a Micro-TPC Matrix of Chambers of Helium 3 for Axial Direct Detection of Non-Baryonic Dark Matter

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    MIMAC-He3 (MIcro-tpc MAtrix of Chambers of Helium 3) is a project for direct detection of non-baryonic dark matter search using He3 as sensitive medium. The priviledged properties of He3 are highlighted. The double detection : ionization and track projection, is explained and rejection evaluated. A phenomenological study in effective SUSY models has been to investigate the MIMAC-He3 complementarity with respect to existing Dark Matter detectors.Comment: 4 pages, 6 figures, to appear in Proceedings of the Rencontres de Moriond 2005 : Very High Energy Phenomena in the Univers

    The role of fiscal rules and institutions in shaping budgetary outcomes

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    The Workshop "The role of fiscal rules and institutions in shaping budgetary outcomes" organized by the Directorate-General for Economic and Financial affairs of the European Commission on 24 November 2006 in Brussels aimed at enriching the debate on the fiscal arrangements and improving the understanding of their functioning. This Economic Paper contains all the paper presented in this event that was organised in four sessions. A first set of papers mainly focus on the impact of numerical fiscal rules on budgetary outturns. Other paper deal primarily with the appropriate design of fiscal rules and institutions. An additional group of papers addresses the relationship between the fiscal governance approach adopted by the EU Member States and their institutional and political frameworks. Finally the remaining presentations relate more directly to policy experiences. fiscal rules, budget, institutions.fiscal rules, budget, institutions, Ayuso-i-Casals, Deroose, Flores, Moulin

    MIMAC-He3 : A Micro-TPC Matrix of Chambers of He3 for direct detection of Wimps

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    The project of a micro-TPC matrix of chambers of \hetrois for direct detection of non-baryonic dark matter is presented. The privileged properties of He3 are highlighted. The double detection (ionization - projection of tracks) is explained and its rejection evaluated. The potentialities of MIMAC-He3 for supersymmetric dark matter search are discussed.Comment: to appear in Proc. of the 9th International Conference on Topics in Astroparticle and Underground Physics (TAUP 2005), Zaragoza, Sept. 200

    Uncertainties on mean areal precipitation: assessment and impact on streamflow simulations

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    International audienceThis paper investigates the influence of mean areal rainfall estimation errors on a specific case study: the use of lumped conceptual rainfall-runoff models to simulate the flood hydrographs of three small to medium-sized catchments of the upper Loire river. This area (3200 km2) is densely covered by an operational network of stream and rain gauges. It is frequently exposed to flash floods and the improvement of flood forecasting models is then a crucial concern. Particular attention has been drawn to the development of an error model for rainfall estimation consistent with data in order to produce realistic streamflow simulation uncertainty ranges. The proposed error model combines geostatistical tools based on kriging and an autoregressive model to account for temporal dependence of errors. It has been calibrated and partly validated for hourly mean areal precipitation rates. Simulated error scenarios were propagated into two calibrated rainfall-runoff models using Monte Carlo simulations. Three catchments with areas ranging from 60 to 3200 km2 were tested to reveal any possible links between the sensitivity of the model outputs to rainfall estimation errors and the size of the catchment. The results show that a large part of the rainfall-runoff (RR) modelling errors can be explained by the uncertainties on rainfall estimates, especially in the case of smaller catchments. These errors are a major factor limiting accuracy and sharpness of rainfallrunoff simulations, and thus their operational use for flood forecasting
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