1,684 research outputs found

    The analysis of the charmonium-like states X(3860)X^{*}(3860),X(3872)X(3872), X(3915)X(3915), X(3930)X(3930) and X(3940)X(3940) according to its strong decay behaviors

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    Inspired by the newly observed state X(3860)X^{*}(3860), we analyze the strong decay behaviors of some charmonium-like states X(3860)X^{*}(3860),X(3872)X(3872), X(3915)X(3915), X(3930)X(3930) and X(3940)X(3940) by the 3P0^{3}P_{0} model. We carry out our work based on the hypothesis that these states are all being the charmonium systems. Our analysis indicates that 0++0^{++} charmonium state can be a good candidate for X(3860)X^{*}(3860) and 1++1^{++} state is the possible assignment for X(3872)X(3872). Considering as the 31S03^{1}S_{0} state, the decay behavior of X(3940)X(3940) is inconsistent with the experimental data. So, we can not assign X(3940)X(3940) as the 31S03^{1}S_{0} charmonium state by present work. Besides, our analysis imply that it is reasonable to assign X(3915)X(3915) and X(3930)X(3930) to be the same state, 2++2^{++}. However, combining our analysis with that of Zhou~\cite{ZhouZY}, we speculate that X(3915)X(3915)/X(3930)X(3930) might not be a pure ccc\overline{c} systems

    Analysis of the strong coupling form factors of ΣbNB\Sigma_bNB and ΣcND\Sigma_c ND in QCD sum rules

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    In this article, we study the strong interaction of the vertexes ΣbNB\Sigma_bNB and ΣcND\Sigma_c ND using the three-point QCD sum rules under two different dirac structures. Considering the contributions of the vacuum condensates up to dimension 55 in the operation product expansion, the form factors of these vertexes are calculated. Then, we fit the form factors into analytical functions and extrapolate them into time-like regions, which giving the coupling constant. Our analysis indicates that the coupling constant for these two vertexes are GΣbNB=0.43±0.01GeV1G_{\Sigma_bNB}=0.43\pm0.01GeV^{-1} and GΣcND=3.76±0.05GeV1G_{\Sigma_cND}=3.76\pm0.05GeV^{-1}.Comment: 6 figure

    Strong coupling constants and radiative decays of the heavy tensor mesons

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    In this article, we analyze tensor-vector-pseudoscalar(TVP) type of vertices D2+D+ρD_{2}^{*+}D^{+}\rho, D20D0ρD_{2}^{*0}D^{0}\rho, D2+D+ωD_{2}^{*+}D^{+}\omega, D20D0ωD_{2}^{*0}D^{0}\omega, B2+B+ρB_{2}^{*+}B^{+}\rho, B20B0ρB_{2}^{*0}B^{0}\rho, B2+B+ωB_{2}^{*+}B^{+}\omega, B20B0ωB_{2}^{*0}B^{0}\omega, Bs2BsϕB_{s2}^{*}B_{s}\phi and Ds2DsϕD_{s2}^{*}D_{s}\phi, in the frame work of three point QCD sum rules. According to these analysis, we calculate their strong form factors which are used to fit into analytical functions of Q2Q^{2}. Then, we obtain the strong coupling constants by extrapolating these strong form factors into deep time-like regions. As an application of this work, the coupling constants for radiative decays of these heavy tensor mesons are also calculated at the point of Q2=0Q^{2}=0. With these coupling constants, we finally calculate the radiative decay widths of these tensor mesons.Comment: arXiv admin note: text overlap with arXiv:1810.0597

    Analysis of the charmed mesons D1(2680)D_{1}^{*}(2680), D3(2760)D_{3}^{*}(2760) and D2(3000)D_{2}^{*}(3000)

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    In this work, we systematically study the strong decay behaviors of the charmed mesons D1(2680)D_{1}^{*}(2680), D3(2760)D_{3}^{*}(2760) and D2(3000)D_{2}^{*}(3000) reported by the LHCb collaboration. By comparing the masses and the decay properties with the results of the experiment, we assigned these newly observed mesons as the 2S1212S\frac{1}{2}1^{-}, 1D5231D\frac{5}{2}3^{-} and 1F522+1F\frac{5}{2}2^{+} states respectively. As a byproduct, we also study the strong decays of the unobserved 2P322+2P\frac{3}{2}2^{+} and 2F522+2F\frac{5}{2}2^{+} charmed mesons, which is helpful to the future experiments in searching for these charmed mesons.Comment: arXiv admin note: text overlap with arXiv:0803.0106 by other author

    Systematic analysis of the DJ(2580)D_{J}(2580), DJ(2650)D_{J}^{*}(2650), DJ(2740)D_{J}(2740), DJ(2760)D_{J}^{*}(2760), DJ(3000)D_{J}(3000) and DJ(3000)D_{J}^{*}(3000) in DD meson family

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    In this work, we tentatively assign the charmed mesons DJ(2580)D_{J}(2580), DJ(2650)D_{J}^{*}(2650), DJ(2740)D_{J}(2740), DJ(2760)D_{J}^{*}(2760), DJ(3000)D_{J}(3000) and DJ(3000)D_{J}^{*}(3000) observed by the LHCb collaboration according to their spin-parity and masses, then study their strong decays to the ground state charmed mesons plus light pseudoscalar mesons with the 3P0^{3}P_{0} model. According to these study, we assigned the DJ(2760)D_{J}^{*}(2760) as the 1D5231D\frac{5}{2}3^{-} state, the DJ(3000)D_{J}^{*}(3000) as the 1F522+1F\frac{5}{2}2^{+} or 1F724+1F\frac{7}{2}4^{+} state, the DJ(3000)D_{J}(3000) as the 1F723+1F\frac{7}{2}3^{+} or 2P121+2P\frac{1}{2}1^{+} state in the DD meson family. As a byproduct, we also study the strong decays of 2P120+2P\frac{1}{2}0^{+},2P322+2P\frac{3}{2}2^{+}, 3S1213S\frac{1}{2}1^{-}, 3S1203S\frac{1}{2}0^{-} etc, states, which will be helpful to further experimentally study mixings of these DD mesons.Comment: 16 pages,1 figure. arXiv admin note: text overlap with arXiv:0801.4821 by other author

    Analysis of the strong vertices of ΣcND\Sigma_cND^{*} and ΣbNB\Sigma_bNB^{*} in QCD sum rules

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    The strong coupling constant is an important parameter which can help us to understand the strong decay behaviors of baryons. In our previous work, we have analyzed strong vertices ΣcND\Sigma_{c}^{*}ND, ΣbNB\Sigma_{b}^{*}NB, ΣcND\Sigma_{c}ND, ΣbNB\Sigma_{b}NB in QCD sum rules. Following these work, we further analyze the strong vertices ΣcND\Sigma_{c}ND^{*} and ΣbNB\Sigma_{b}NB^{*} using the three-point QCD sum rules under Dirac structures q ⁣ ⁣ ⁣/p ⁣ ⁣ ⁣/γαq\!\!\!/p\!\!\!/\gamma_{\alpha} and q ⁣ ⁣ ⁣/p ⁣ ⁣ ⁣/pαq\!\!\!/p\!\!\!/p_{\alpha}. In this work, we first calculate strong form factors considering contributions of the perturbative part and the condensate terms qq\langle\overline{q}q\rangle, αsπGG\langle\frac{\alpha_{s}}{\pi}GG\rangle and qgsσGq\langle\overline{q}g_{s}\sigma Gq\rangle. Then, these form factors are used to fit into analytical functions. According to these functions, we finally determine the values of the strong coupling constants for these two vertices ΣcND\Sigma_{c}ND^{*} and ΣbNB\Sigma_{b}NB^{*}.Comment: arXiv admin note: text overlap with arXiv:1705.0322

    Comparative study of earthquake-related and non-earthquake-related head traumas using multidetector computed tomography

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    OBJECTIVE: The features of earthquake-related head injuries may be different from those of injuries obtained in daily life because of differences in circumstances. We aim to compare the features of head traumas caused by the Sichuan earthquake with those of other common head traumas using multidetector computed tomography. METHODS: In total, 221 patients with earthquake-related head traumas (the earthquake group) and 221 patients with other common head traumas (the non-earthquake group) were enrolled in our study, and their computed tomographic findings were compared. We focused the differences between fractures and intracranial injuries and the relationships between extracranial and intracranial injuries. RESULTS: More earthquake-related cases had only extracranial soft tissue injuries (50.7% vs. 26.2%, RR=1.9), and fewer cases had intracranial injuries (17.2% vs. 50.7%, RR = 0.3) compared with the non-earthquake group. For patients with fractures and intracranial injuries, there were fewer cases with craniocerebral injuries in the earthquake group (60.6% vs. 77.9%, RR = 0.8), and the earthquake-injured patients had fewer fractures and intracranial injuries overall (1.5 + 0.9 vs. 2.5 +1.8; 1.3 + 0.5 vs. 2.1 + 1.1). Compared with the non-earthquake group, the incidences of soft tissue injuries and cranial fractures combined with intracranial injuries in the earthquake group were significantly lower (9.8% vs. 43.7%, RR = 0.2; 35.1% vs. 82.2%, RR = 0.4). CONCLUSION: As depicted with computed tomography, the severity of earthquake-related head traumas in survivors was milder, and isolated extracranial injuries were more common in earthquake-related head traumas than in non-earthquake-related injuries, which may have been the result of different injury causes, mechanisms and settings
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