5,858 research outputs found

    Could Zc(4025)Z_{c}(4025) be a JP=1+J^{P}=1^{+} DDˉD^{*}\bar{D^{*}} molecular state?

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    We investigate whether the newly observed narrow resonance Zc(4025)Z_{c}(4025) can be described as a DDˉD^{*}\bar{D^{*}} molecular state with quantum numbers JP=1+J^{P}=1^{+}. Using QCD sum rules, we consider contributions up to dimension six in the operator product expansion and work at leading order of αs\alpha_{s}. The mass obtained for this state is (4.05\pm 0.28) \mbox{GeV}. It is concluded that DDˉD^{*}\bar{D^{*}} molecular state is a possible candidate for Zc(4025)Z_{c}(4025).Comment: 7 pages, 4 figures.Published in Eur.Phys.J. C73 (2013) 2661. arXiv admin note: text overlap with arXiv:1304.185

    Higher order light-cone distribution amplitudes of the Lambda baryon

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    The improved light-cone distribution amplitudes (LCDAs) of the Λ\Lambda baryon are examined on the basis of the QCD conformal partial wave expansion approach. The calculations are carried out to the next-to-leading order of conformal spin accuracy with consideration of twist 6. The next leading order conformal expansion coefficients are related to the nonperturbative parameters defined by the local three quark operator matrix elements with different Lorentz structures with a covariant derivative. The nonperturbative parameters are determined with the QCD sum rule method. The explicit expressions of the LCDAs are provided as the main results.Comment: 17pages,10figures. arXiv admin note: text overlap with arXiv:1311.596

    Cascading failures in coupled networks with both inner-dependency and inter-dependency links

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    We study the percolation in coupled networks with both inner-dependency and inter-dependency links, where the inner- and inter-dependency links represent the dependencies between nodes in the same or different networks, respectively. We find that when most of dependency links are inner- or inter-ones, the coupled networks system is fragile and makes a discontinuous percolation transition. However, when the numbers of two types of dependency links are close to each other, the system is robust and makes a continuous percolation transition. This indicates that the high density of dependency links could not always lead to a discontinuous percolation transition as the previous studies. More interestingly, although the robustness of the system can be optimized by adjusting the ratio of the two types of dependency links, there exists a critical average degree of the networks for coupled random networks, below which the crossover of the two types of percolation transitions disappears, and the system will always demonstrate a discontinuous percolation transition. We also develop an approach to analyze this model, which is agreement with the simulation results well.Comment: 9 pages, 4 figure
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