2,590,023 research outputs found

    137Cs measurement uncertainties and detection limits for airborne gamma spectrometry (AGS) data analysed using a spectral windows method

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    The uncertainties associated with airborne gamma spectrometry (AGS) measurements analysed using a spectral windows method, and associated detection limits, have been investigated. For individual short measurements over buried 137Cs activity detection limits of are achieved. These detection limits are reduced for superficial activity and longer integration times. For superficial activity, detection limits below are achievable. A comparison is made with the detection limits for other data processing methods

    Limits on dark matter proton scattering from neutrino telescopes using micrOMEGAs

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    Limits on dark matter spin dependent elastic scattering cross section on protons derived from IceCube data are obtained for different dark matter annihilation channels using micrOMEGAs. The uncertainty on the derived limits, estimated by using different neutrino spectra, can reach a factor two. For all dark matter annihilation channels except for quarks, the limits on the spin dependent cross section are more stringent than those obtained in direct detection experiments. The new functions that allow to derive those limits are described.Comment: 23 pages, 7 figures; v2: references added; v3 and v4: clarifications added; The code can be downloaded from https://lapth.cnrs.fr/micromega

    The HI Content of Compact Groups of Galaxies

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    The HI content of Hickson Compact Groups in the southern hemisphere is measured using data from the HI Parkes All Sky Survey (HIPASS), and dedicated observations using the narrowband filter on the Multibeam instrument on the Parkes telescope. The expected HI mass of these groups was estimated using the luminosity, diameter and morphological types of the member galaxies, calibrated from published data. Taking careful account of non-detection limits, the results show that the compact group population that has been detected by these observations has an HI content similar to that of galaxies in the reference field sample. The upper limits for the undetected groups lie within the normal range; improvement of these limits will require a large increase in sensitivity.Comment: 27 pages, 5 figures. Accepted for publication in PAS

    Interpreting the bounds on Solar Dark Matter induced muons at Super-Kamiokande in the light of CDMS results

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    We consider the recent limits on dark matter - nucleon elastic scattering cross section from the analysis of CDMS II collaboration using the two signal events observed in CDMS experiment. With these limits we try to interpret the Super-Kamiokande (SK) bounds on the detection rates of up-going muons induced by the neutrinos that are produced in the sun from the decay of annihilation products of dark matter (WIMPs) captured in the solar core. Calculated rates of up-going muons for different annihilation channels at SK using CDMS bounds are found to be orders below the predicted upper limits of such up-going muon rates at SK. Thus there exists room for enhancement (boost) of the calculated rates using CDMS limits for interpreting SK bounds. Such a feature is expected to represent the PAMELA data with the current CDMS limits. We also show the dependence of such a possible enhancement factor (boost) on WIMP mass for different WIMP annihilation channels.Comment: 7 pages, 6 figure

    Extending the CRESST-II commissioning run limits to lower masses

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    Motivated by the recent interest in light WIMPs of mass ~O(10 GeV), an extension of the elastic, spin-independent WIMP-nucleon cross-section limits resulting from the CRESST-II commissioning run (2007) are presented. Previously, these data were used to set cross-section limits from 1000 GeV down to ~17 GeV, using tungsten recoils, in 47.9 kg-days of exposure of calcium tungstate. Here, the overlap of the oxygen and calcium bands with the acceptance region of the commissioning run data set is reconstructed using previously published quenching factors. The resulting elastic WIMP cross section limits, accounting for the additional exposure of oxygen and calcium, are presented down to 5 GeV.Comment: 4 pages, 4 figure

    Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV

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    A search for new physics is presented based on an event signature of at least three jets accompanied by large missing transverse momentum, using a data sample corresponding to an integrated luminosity of 36 inverse picobarns collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector at the LHC. No excess of events is observed above the expected standard model backgrounds, which are all estimated from the data. Exclusion limits are presented for the constrained minimal supersymmetric extension of the standard model. Cross section limits are also presented using simplified models with new particles decaying to an undetected particle and one or two jets
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