10,614 research outputs found

    Constraints on Dark Energy Models Including Gamma Ray Bursts

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    In this paper we analyze the constraints on the property of dark energy from cosmological observations. Together with SNe Ia Gold sample, WMAP, SDSS and 2dFGRS data, we include 69 long Gamma-Ray Bursts (GRBs) data in our study and perform global fitting using Markov Chain Monte Carlo (MCMC) technique. Dark energy perturbations are explicitly considered. We pay particular attention to the time evolution of the equation of state of dark energy parameterized as wDE=w0+wa(1βˆ’a)w_{DE}=w_0+w_a(1-a) with aa the scale factor of the universe, emphasizing the complementarity of high redshift GRBs to other cosmological probes. It is found that the constraints on dark energy become stringent by taking into account high redshift GRBs, especially for waw_a, which delineates the evolution of dark energy.Comment: 7 pages and 3 figures. Replaced with version accepted for publication in Phys. Lett.

    Energy Forecasting with Building Characteristics Analysis

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    With the installation of smart meters, high resolution building-level energy consumption data become increasingly accessible, which not only provides more accurate data for energy forecasting at the aggregated level but also enables datadriven energy forecasting for individual buildings. On the one hand, individual buildings exhibit high randomness, making the forecasting problem at the building-level more challenging. On the other hand, buildings usually have their own characteristics, therefore such valuable information needs to be considered in the forecast models at the aggregation level. In this paper we investigate how unique characteristics of buildings could affect the performance of forecasting models and aim to identify defining patterns of buildings. The usefulness of the proposed approach is demonstrated using data from three real-world buildings

    On the Nature of X(4260)

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    We study the property of X(4260)X(4260) resonance by re-analyzing all experimental data available, especially the e+eβˆ’β†’J/Οˆβ€‰Ο€+Ο€βˆ’,   ωχc0e^+e^- \rightarrow J/\psi\,\pi^+\pi^-,\,\,\,\omega\chi_{c0} cross section data. The final state interactions of the ππ\pi\pi, KKΛ‰K\bar K couple channel system are also taken into account. A sizable coupling between the X(4260)X(4260) and ωχc0\omega\chi_{c0} is found. The inclusion of the ωχc0\omega\chi_{c0} data indicates a small value of Ξ“e+eβˆ’=23.30Β±3.55\Gamma_{e^+e^-}=23.30\pm 3.55eV.Comment: Refined analysis with new experimental data included. 13 page
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