1,084 research outputs found

    Bose-Einstein Correlations and Sonoluminescence

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    Sonoluminescence may be studied in detail by intensity correlations among the emitted photons. As an example, we discuss an experiment to measure the size of the light-emitting region by the Hanbury Brown-Twiss effect. We show that single bubble sonoluminescence is almost ideally suited for study by this method and that plausible values for the physical parameters are within easy experimental reach. A sequence of two and higher order photon correlation experiments is outlined.Comment: Latex File, 8 pages, Postscript file with 2 figs. attache

    Shape parametrization for liquid-drop studies

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    We present a new method for defining axially symmetric shapes which is particularly appropriate for describing elongated and multineck configurations. This shape parametrization is used to describe the static properties of incompressible, charged liquid drops. In particular, we calculate the properties of binary-fission saddle points and compare these with results using other methods. We also present the geometrical properties and normal mode analyses of the two-and three-necked saddle-point families

    Sonoluminescence: Two-photon correlations as a test of thermality

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    In this Letter we propose a fundamental test for probing the thermal nature of the spectrum emitted by sonoluminescence. We show that two-photon correlations can in principle discriminate between real thermal light and the quasi-thermal squeezed-state photons typical of models based on the dynamic Casimir effect. Two-photon correlations provide a powerful experimental test for various classes of sonoluminescence models.Comment: 6 pages, revtex 3; revised to include more discussion of finite volume effects; physics conclusions unchanged; to appear in Physics Letters

    Antibiotic de-escalation experience in the setting of emergency department: A retrospective, observational study

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    Background: Antimicrobial de-escalation (ADE) is a part of antimicrobial stewardship strategies aiming to minimize unnecessary or inappropriate antibiotic exposure to decrease the rate of antimicrobial resistance. Information regarding the effectiveness and safety of ADE in the setting of emergency medicine wards (EMW) is lacking. Methods: Adult patients admitted to EMW and receiving empiric antimicrobial treatment were retrospectively studied. The primary outcome was the rate and timing of ADE. Secondary outcomes included factors associated with early ADE, length of stay, and in-hospital mortality. Results: A total of 336 patients were studied. An initial regimen combining two agents was prescribed in 54.8%. Ureidopenicillins and carbapenems were the most frequently empiric treatment prescribed (25.1% and 13.6%). The rate of the appropriateness of prescribing was 58.3%. De-escalation was performed in 111 (33%) patients. Patients received a successful de-escalation on day 2 (21%), 3 (23%), and 5 (56%). The overall in-hospital mortality was 21%, and it was significantly lower among the de-escalation group than the continuation group (16% vs 25% p = 0.003). In multivariate analysis, de-escalation strategies as well as appropriate empiric and targeted therapy were associated with reduced mortality. Conclusions: ADE appears safe and effective in the setting of EMWs despite that further research is warranted to confirm these findings

    The STAR Time Projection Chamber: A Unique Tool for Studying High Multiplicity Events at RHIC

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    The STAR Time Projection Chamber (TPC) is used to record collisions at the Relativistic Heavy Ion Collider (RHIC). The TPC is the central element in a suite of detectors that surrounds the interaction vertex. The TPC provides complete coverage around the beam-line, and provides complete tracking for charged particles within +- 1.8 units of pseudo-rapidity of the center-of-mass frame. Charged particles with momenta greater than 100 MeV/c are recorded. Multiplicities in excess of 3,000 tracks per event are routinely reconstructed in the software. The TPC measures 4 m in diameter by 4.2 m long, making it the largest TPC in the world.Comment: 28 pages, 11 figure

    Search for Neutrinoless Double-Beta Decay of 130^{130}Te with CUORE-0

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    We report the results of a search for neutrinoless double-beta decay in a 9.8~kg⋅\cdotyr exposure of 130^{130}Te using a bolometric detector array, CUORE-0. The characteristic detector energy resolution and background level in the region of interest are 5.1±0.3 keV5.1\pm 0.3{\rm~keV} FWHM and 0.058±0.004 (stat.)±0.002 (syst.)0.058 \pm 0.004\,(\mathrm{stat.})\pm 0.002\,(\mathrm{syst.})~counts/(keV⋅\cdotkg⋅\cdotyr), respectively. The median 90%~C.L. lower-limit sensitivity of the experiment is 2.9×1024 yr2.9\times 10^{24}~{\rm yr} and surpasses the sensitivity of previous searches. We find no evidence for neutrinoless double-beta decay of 130^{130}Te and place a Bayesian lower bound on the decay half-life, T1/20Îœ>T^{0\nu}_{1/2}>~2.7×1024 yr 2.7\times 10^{24}~{\rm yr} at 90%~C.L. Combining CUORE-0 data with the 19.75~kg⋅\cdotyr exposure of 130^{130}Te from the Cuoricino experiment we obtain T1/20Îœ>4.0×1024 yrT^{0\nu}_{1/2} > 4.0\times 10^{24}~\mathrm{yr} at 90%~C.L.~(Bayesian), the most stringent limit to date on this half-life. Using a range of nuclear matrix element estimates we interpret this as a limit on the effective Majorana neutrino mass, mÎČÎČ<270m_{\beta\beta}< 270 -- 760 meV760~\mathrm{meV}.Comment: 6 pages, 5 figures, updated version as published in PR

    Analysis Techniques for the Evaluation of the Neutrinoless Double-Beta Decay Lifetime in 130^{130}Te with CUORE-0

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    We describe in detail the methods used to obtain the lower bound on the lifetime of neutrinoless double-beta (0ÎœÎČÎČ0\nu\beta\beta) decay in 130^{130}Te and the associated limit on the effective Majorana mass of the neutrino using the CUORE-0 detector. CUORE-0 is a bolometric detector array located at the Laboratori Nazionali del Gran Sasso that was designed to validate the background reduction techniques developed for CUORE, a next-generation experiment scheduled to come online in 2016. CUORE-0 is also a competitive 0ÎœÎČÎČ0\nu\beta\beta decay search in its own right and functions as a platform to further develop the analysis tools and procedures to be used in CUORE. These include data collection, event selection and processing, as well as an evaluation of signal efficiency. In particular, we describe the amplitude evaluation, thermal gain stabilization, energy calibration methods, and the analysis event selection used to create our final 0ÎœÎČÎČ0\nu\beta\beta decay search spectrum. We define our high level analysis procedures, with emphasis on the new insights gained and challenges encountered. We outline in detail our fitting methods near the hypothesized 0ÎœÎČÎČ0\nu\beta\beta decay peak and catalog the main sources of systematic uncertainty. Finally, we derive the 0ÎœÎČÎČ0\nu\beta\beta decay half-life limits previously reported for CUORE-0, T1/20Îœ>2.7×1024T^{0\nu}_{1/2}>2.7\times10^{24} yr, and in combination with the Cuoricino limit, T1/20Îœ>4.0×1024T^{0\nu}_{1/2}>4.0\times10^{24} yr.Comment: 18 pages, 18 figures. (Version 3 reflects only minor changes to the text. Few additional details, no major content changes.

    CUORE-0 results and prospects for the CUORE experiment

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    With 741 kg of TeO2 crystals and an excellent energy resolution of 5 keV (0.2%) at the region of interest, the CUORE (Cryogenic Underground Observatory for Rare Events) experiment aims at searching for neutrinoless double beta decay of 130Te with unprecedented sensitivity. Expected to start data taking in 2015, CUORE is currently in an advanced construction phase at LNGS. CUORE projected neutrinoless double beta decay half-life sensitivity is 1.6E26 y at 1 sigma (9.5E25 y at the 90% confidence level), in five years of live time, corresponding to an upper limit on the effective Majorana mass in the range 40-100 meV (50-130 meV). Further background rejection with auxiliary bolometric detectors could improve CUORE sensitivity and competitiveness of bolometric detectors towards a full analysis of the inverted neutrino mass hierarchy. CUORE-0 was built to test and demonstrate the performance of the upcoming CUORE experiment. It consists of a single CUORE tower (52 TeO2 bolometers of 750 g each, arranged in a 13 floor structure) constructed strictly following CUORE recipes both for materials and assembly procedures. An experiment its own, CUORE-0 is expected to reach a sensitivity to the neutrinoless double beta decay half-life of 130Te around 3E24 y in one year of live time. We present an update of the data, corresponding to an exposure of 18.1 kg y. An analysis of the background indicates that the CUORE performance goal is satisfied while the sensitivity goal is within reach.Comment: 10 pages, 3 figures, to appear in the proceedings of NEUTRINO 2014, 26th International Conference on Neutrino Physics and Astrophysics, 2-7 June 2014, held at Boston, Massachusetts, US
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