420 research outputs found

    Extracting constraints from direct detection searches of supersymmetric dark matter in the light of null results from the LHC in the squark sector

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    The comparison of the results of direct detection of Dark Matter, obtained with various target nuclei, requires model-dependent, or even arbitrary, assumptions. Indeed, to draw conclusions either the spin-dependent (SD) or the spin-independent (SI) interaction has to be neglected. In the light of the null results from supersymmetry searches at the LHC, the squark sector is pushed to high masses. We show that for a squark sector at the TeV scale, the framework used to extract contraints from direct detection searches can be redefined as the number of free parameters is reduced. Moreover, the correlation observed between SI and SD proton cross sections constitutes a key issue for the development of the next generation of Dark Matter detectors.Comment: Figure 3 has been updated. Conclusions unchange

    A superfluid He3 detector for direct dark matter search

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    MACHe3 (MAtrix of Cells of superfluid He3) is a project of a new detector for direct Dark Matter Search. The idea is to use superfluid He3 as a sensitive medium. The existing device, the superfluid He3 cell, will be briefly introduced. Then a description of the MACHe3 project will be presented, in particular the background rejection and the neutralino event rate that may be achieved with such a device.Comment: 6 pages, 3 figures, Proceedings of the 3rd International Workshop on the Identification of Dark Matter (York, UK, 09/18/2000-09/22/2000

    A project of a new detector for direct Dark Matter search: MACHe3

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    MACHe3 (MAtrix of Cells of superfluid He3) is a project of a new detector for direct Dark Matter (DM) search. A cell of superfluid He3 has been developed and the idea of using a large number of such cells in a high granularity detector is proposed.This contribution presents, after a brief description of the superfluid He3 cell, the simulation of the response of different matrix configurations allowing to define an optimum design as a function of the number of cells and the volume of each cell. The exclusion plot and the predicted interaction cross-section for the neutralino as a photino are presented.Comment: 8 pages, 7 figures, Proceedings of Dark Matter 2000 (Marina Del Rey, Los Angeles, USA, 02/23/2000-02/25/2000

    Risk factors for coronary heart disease in the white community of Durban

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    Coronary heart disease (CHD) is the leading cause of death among the white and Indian populations of Durban. This was a community-based study of the white population of Durban, which is predominantly English-speaking. There were 396 subjects (194 men, 202 women) aged 15 - 69 years. A history of CHD was present in 9,3% of the subjects. The important risk factors were hypercholesterolaemia, hypertension and smoking. The minor risk factors were obesity, hypertriglyceridaemia, hypeuricaemia, a sedentary occupation and a history of CHD in the immediate family. Electrocardiograph abnormalities denoting CHD were present in 17% of subjects. A study of the major risk factors showed that 35,1% (age and sex adjusted) had at least one major risk factor at the higher level (level A) and 33,8% (age and sex adjusted) at the lower risk levels (level B). When the combination of risk factors was taken into account, 15,2% and 28% had two major risk factors, one each at levels A and B respectively. On average the percentage of men and women with one risk factor or more increased with age. A protective high-density lipoprotein/total cholesterol ratio≥20% was present in 53,5% of the respondents. Because of the severe nature of CHD, an intensive programme for the primary prevention of CHD risk factors should be instituted

    Design optimization of MACHe3, a project of superfuid 3He^{3}He Detector for direct Dark Matter search

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    MACHe3 (MAtrix of Cells of superfluid He3) is a project of a new detector fordirect Dark Matter (DM) search. A cell of superfluid He3 has been developed andthe idea of using a large number of such cells in a high granularity detectoris proposed. This paper presents, after a brief description of the superfluidHe3 cell, the simulation of the response of different matrix configurationsallowing to define an optimum design as a function of the number of cells andthe volume of each cell. The background rejection, for several configurations,is presented both for neutrons and gamma-rays of various kinetic energies

    Risk factors for coronary heart disease in the Indians of Durban

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    Coronary heart disease (CHD) is a major problem in migrant Indians throughout the world. In South Africa it has reached 'epidemic' proportions. A field survey was conducted among Indians in the metropolitan area of Durban to determine the prevalence and known risk factors for CHD. In a study of 778 subjects aged 15 - 69 years (408 men), 15,3% (sex and age adjusted 13,4%) had a history of CHD. The important risk factors in men were hypercholesterolaemia, hypertriglyceridaemia, diabetes, and smoking, and in women diabetes, hypercholesterolaemia, and hypertriglyceridaemia. The minor risk factors were hyperuricaemia, sedentary occupation, obesity in women and a positive family history of CHD. A study of the major risk factors leading to CHD showed that 52% (sex and age adjusted 45,5%) had at least one major risk factor at the higher (level A) and 68% (sex and age adjusted 61,9%) at the lower (level B) risk levels. Diabetes mellitus was strongly associated with a positive history of CHD. In 47,6% (sex and age adjusted 48,2%) of the total group resting ECG abnormalities were found that could be coded. Because of the severe nature of CHD in the migrant Indian, an immediate and intensive programme of primary prevention of CHD risk factors should be instituted

    MACHe3: A new generation detector for non-baryonic dark matter direct detection

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    MACHe3 (MAtrix of Cells of superfluid He3) is a project of a new detector for direct Dark Matter (DM) search, using superfluid as a sensitive medium. An experiment on a prototype cell has been performed and the first results reported here are encouraging to develop of a multicell prototype. In order to investigate the discovery potential of MACHe3, and its complementarity with other DM detectors, a phenomenological study done with the DarkSUSY code is shown.Comment: 6 pages, 3 figures, Proceedings of the 4th International Workshop on the Identification of Dark Matter (York, UK, 09/02/2002-09/06/2002

    Sub-wavelength surface IR imaging of soft-condensed matter

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    Outlined here is a technique for sub-wavelength infrared surface imaging performed using a phase matched optical parametric oscillator laser and an atomic force microscope as the detection mechanism. The technique uses a novel surface excitation illumination approach to perform simultaneously chemical mapping and AFM topography imaging with an image resolution of 200 nm. This method was demonstrated by imaging polystyrene micro-structures

    NIKA2: a mm camera for cluster cosmology

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    Galaxy clusters constitute a major cosmological probe. However, Planck 2015 results have shown a weak tension between CMB-derived and cluster-derived cosmological parameters. This tension might be due to poor knowledge of the cluster mass and observable relationship. As for now, arcmin resolution Sunyaev-Zeldovich (SZ) observations ({\it e.g.} SPT, ACT and Planck) only allowed detailed studies of the intra cluster medium for low redshift clusters (z0.5z0.5) high resolution and high sensitivity SZ observations are needed. With both a wide field of view (6.5 arcmin) and a high angular resolution (17.7 and 11.2 arcsec at 150 and 260 GHz), the NIKA2 camera installed at the IRAM 30-m telescope (Pico Veleta, Spain) is particularly well adapted for these observations. The NIKA2 SZ observation program will map a large sample of clusters (50) at redshifts between 0.5 and 0.9. As a pilot study for NIKA2, several clusters of galaxies have been observed with the pathfinder, NIKA, at the IRAM 30-m telescope to cover the various configurations and observation conditions expected for NIKA2.

    First Results on In-Beam gamma Spectroscopy of Neutron-Rich Na and Mg Isotopes at REX-ISOLDE

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    After the successful commissioning of the radioactive beam experiment at ISOLDE (REX-ISOLDE) - an accelerator for exotic nuclei produced by ISOLDE - first physics experiments using these beams were performed. Initial experiments focused on the region of deformation in the vicinity of the neutron-rich Na and Mg isotopes. Preliminary results show the high potential and physics opportunities offered by the exotic isotope accelerator REX in conjunction with the modern Germanium gamma spectrometer MINIBALL.Comment: 7 pages, RNB6 conference contributio
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