21,390 research outputs found

    Searching for high-KK isomers in the proton-rich A∼80A\sim80 mass region

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    Configuration-constrained potential-energy-surface calculations have been performed to investigate the KK isomerism in the proton-rich A∼80A\sim80 mass region. An abundance of high-KK states are predicted. These high-KK states arise from two and four-quasi-particle excitations, with Kπ=8+K^{\pi}=8^{+} and Kπ=16+K^{\pi}=16^{+}, respectively. Their excitation energies are comparatively low, making them good candidates for long-lived isomers. Since most nuclei under studies are prolate spheroids in their ground states, the oblate shapes of the predicted high-KK states may indicate a combination of KK isomerism and shape isomerism

    Time-Series Analysis of Super-Kamiokande Measurements of the Solar Neutrino Flux

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    The Super-Kamiokande Consortium has recently released data suitable for time-series analysis. The binning is highly regular: the power spectrum of the acquisition times has a huge peak (power S > 120) at the frequency (in cycles per year) 35.98 (period 10.15 days), where power measurements are such that the probability of obtaining a peak of strength S or more by chance at a specified frequency is exp(-S). This inevitably leads to severe aliasing of the power spectrum. The strongest peak in the range 0 - 100 in a power spectrum formed by a likelihood procedure is at 26.57 (period 13.75 days) with S = 11.26. For the range 0 - 40, the second-strongest peak is at 9.42 (period 38.82 days) with S = 7.3. Since 26.57 + 9.42 = 35.99, we conclude that the weaker peak at 9.42 is an alias of the stronger peak at 26.57. We note that 26.57 falls in the band 26.36 - 27.66, formed from twice the range of synodic rotation frequencies of an equatorial section of the Sun for normalized radius larger than 0.1. Oscillations at twice the rotation frequency, attributable to "m = 2" structures, are not uncommon in solar data. We find from the shuffle test that the probability of obtaining a peak of S = 11.26 or more by chance in this band is 0.1 %. This new result therefore supports at the 99.9% confidence level previous evidence, found in Homestake and GALLEX-GNO data, for rotational modulation of the solar neutrino flux. The frequency 25.57 points to a source of modulation at or near the tachocline.Comment: 15 pages, 8 figure

    Ratio of Hadronic Decay Rates of J\psi and \psi(2S) and the \rho\pi Puzzle

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    The so-called \rho\pi puzzle of J\psi and \psi(2S) decays is examined using the experimental data available to date. Two different approaches were taken to estimate the ratio of J\psi and \psi(2S) hadronic decay rates. While one of the estimates could not yield the exact ratio of \psi(2S) to J\psi inclusive hadronic decay rates, the other, based on a computation of the inclusive ggg decay rate for \psi(2S) (J\psi) by subtracting other decay rates from the total decay rate, differs by two standard deviations from the naive prediction of perturbative QCD, even though its central value is nearly twice as large as what was naively expected. A comparison between this ratio, upon making corrections for specific exclusive two-body decay modes, and the corresponding experimental data confirms the puzzles in J\psi and \psi(2S) decays. We find from our analysis that the exclusively reconstructed hadronic decays of the \psi(2S) account for only a small fraction of its total decays, and a ratio exceeding the above estimate should be expected to occur for a considerable number of the remaining decay channels. We also show that the recent new results from the BES experiment provide crucial tests of various theoretical models proposed to explain the puzzle.Comment: 8 pages, no figure, 4 table

    An indoor positioning system using Bluetooth Low Energy

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    In this paper, we present a Bluetooth Low Energy (BLE) based indoor positioning system developed for monitoring the daily living pattern of old people (e.g. people living with dementia) or individuals with disabilities. The proposed sensing system is composed of multiple sensors that are installed in different locations in a home environment. The specific location of the user in the building has been pre-recorded into the proposed sensing system that captures the raw Received Signal Strength Indicator (RSSI) from the BLE beacon that is attached on the user. Two methods are proposed to determine the indoor location and the tracking of the users: a trilateration-based method and fingerprinting-based method. Experiments have been carried out in different home environments to verify the proposed system and methods. The results show that our system is able to accurately track the user location in home environments and can track the living patterns of the user which, in turn, may be used to infer the health status of the user. Our results also show that the positions of the BLE beacons on the user and different quality of BLE beacons do not affect the tracking accuracy

    Modified Dispersion Relations: from Black-Hole Entropy to the Cosmological Constant

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    Quantum Field Theory is plagued by divergences in the attempt to calculate physical quantities. Standard techniques of regularization and renormalization are used to keep under control such a problem. In this paper we would like to use a different scheme based on Modified Dispersion Relations (MDR) to remove infinities appearing in one loop approximation in contrast to what happens in conventional approaches. In particular, we apply the MDR regularization to the computation of the entropy of a Schwarzschild black hole from one side and the Zero Point Energy (ZPE) of the graviton from the other side. The graviton ZPE is connected to the cosmological constant by means of of the Wheeler-DeWitt equation.Comment: Contribution prepared for the proceedings of the conference on quantum field theory under the influence of external conditions (QFEXT11). 8 page

    An edge-based matching kernel on commute-time spanning trees

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    Hadronic Contributions to the Photon Vacuum Polarization and their Role in Precision Physics

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    I review recent evaluations of the hadronic contribution to the shift in the fine structure constant and to the anomalous magnetic moment of the muon. Substantial progress in a precise determination of these important observables is a consequence of substantially improved total cross section measurement by the CMD-2 and BES II collaborations and an improved theoretical understanding. Prospects for further possible progress is discussed.Comment: 17 pages 7 figures 2 tables, update: incl. CMD-2 data, reference

    Predicting Objective Function Change in Pose-Graph Optimization

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    Robust online incremental SLAM applications require metrics to evaluate the impact of current measurements. Despite its prevalence in graph pruning, information-theoretic metrics solely are insufficient to detect outliers. The optimal value of the objective function is a better choice to detect outliers but cannot be computed unless the problem is solved. In this paper, we show how the objective function change can be predicted in an incremental pose-graph optimization scheme, without actually solving the problem. The predicted objective function change can be used to guide online decisions or detect outliers. Experiments validate the accuracy of the predicted objective function, and an application to outlier detection is also provided, showing its advantages over M-estimators
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