42,944 research outputs found

    Two-neutrino double electron capture on 124^{124}Xe based on an effective theory and the nuclear shell model

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    We study the two-neutrino double electron capture on 124^{124}Xe based on an effective theory (ET) and large-scale shell model calculations, two modern nuclear structure approaches that have been tested against Gamow-Teller and double-beta decay data. In the ET, the low-energy constants are fit to electron capture and ÎČ−\beta^{-} transitions around xenon. For the nuclear shell model, we use an interaction in a large configuration space that reproduces the spectroscopy of nuclei in this mass region. For the dominant transition to the 124^{124}Te ground state, we find half-lives T1/22ÎœECEC=(1.3−18)×1022T^{2\nu{\rm ECEC}}_{1/2}=(1.3-18)\times 10^{22} y for the ET and T1/22ÎœECEC=(0.43−2.9)×1022T^{2\nu{\rm ECEC}}_{1/2} = (0.43-2.9)\times 10^{22} y for the shell model. The ET uncertainty leads to a half-life almost entirely consistent with present experimental limits and largely within the reach of ongoing experiments. The shell model half-life range overlaps with the ET, but extends less beyond current limits. Our findings thus suggest that the two-neutrino double electron capture on 124^{124}Xe has a good chance to be discovered by ongoing or future experiments. In addition, we present results for the two-neutrino double electron capture to excited states of 124^{124}Te.Comment: 5 pages, 2 figure

    Towards an Ontology Metadata Standard

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    In this poster, we present (i) a proposal for a metadata standard, known as Ontology Metadata Vocabulary (OMV) which is based on discussions in the EU IST thematic network of excellence Knowledge Web1 and (ii) two complementary reference implementations which show the benefit of such a standard in decentralized and centralized scenarios, i.e. the Oyster P2P system and the Onthology metadata portal

    From vertex detectors to inner trackers with CMOS pixel sensors

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    The use of CMOS Pixel Sensors (CPS) for high resolution and low material vertex detectors has been validated with the 2014 and 2015 physics runs of the STAR-PXL detector at RHIC/BNL. This opens the door to the use of CPS for inner tracking devices, with 10-100 times larger sensitive area, which require therefore a sensor design privileging power saving, response uniformity and robustness. The 350 nm CMOS technology used for the STAR-PXL sensors was considered as too poorly suited to upcoming applications like the upgraded ALICE Inner Tracking System (ITS), which requires sensors with one order of magnitude improvement on readout speed and improved radiation tolerance. This triggered the exploration of a deeper sub-micron CMOS technology, Tower-Jazz 180 nm, for the design of a CPS well adapted for the new ALICE-ITS running conditions. This paper reports the R&D results for the conception of a CPS well adapted for the ALICE-ITS.Comment: 4 pages, 4 figures, VCI 2016 conference proceeding
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