2,024 research outputs found

    Inclusive decays of ηb\eta_{b} into SS- and PP-wave charmonium states

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    Inclusive S- and P-wave charmonium productions in the bottomonium ground state ηb\eta_b decay are calculated at the leading order in the strong coupling constant αs\alpha_s and quarkonium internal relative velocity vv in the framework of the NRQCD factorization approach. We find the contribution of ηb→χcJ+gg\eta_b \to \chi_{c_J}+ g g followed by χcJ→J/ψ+Îł\chi_{c_J} \to J/\psi+ \gamma is also very important to the inclusive J/ψJ/\psi production in the ηb\eta_b decays, which maybe helpful to the investigation of the color-octet mechanism in the inclusive J/ψJ/\psi production in the ηb\eta_b decays in the forthcoming LHCb and SuperB. As a complementary work, we also study the inclusive production of ηc\eta_c, and χcJ\chi_{cJ} in the ηb\eta_b decays, which may help us understand the X(3940) and X(3872) states.Comment: 7 pages, 2 figure

    Excited heavy tetraquarks with hidden charm

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    The masses of the excited heavy tetraquarks with hidden charm are calculated within the relativistic diquark-antidiquark picture. The dynamics of the light quark in a heavy-light diquark is treated completely relativistically. The diquark structure is taken into account by calculating the diquark-gluon form factor. New experimental data on charmonium-like states above open charm threshold are discussed. The obtained results indicate that X(3872), Y(4260), Y(4360), Z(4248), Z(4433) and Y(4660) could be tetraquark states with hidden charm.Comment: 11 page

    New aspects of the BMN correspondence beyond the planar limit

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    Motivated by recent disagreements in the context of AdS/CFT, we study the non-planar sector of the BMN correspondence. In particular, we reconsider the energy shift of states with two stringy excitations in light-cone string field theory and explicitly determine its complete perturbative contribution from the impurity-conserving channel. Surprisingly, our result neither agrees with earlier leading order computations, nor reproduces the gauge theory prediction. More than that, it features half-integer powers of the effective gauge coupling λâ€Č\lambda' representing a qualitative difference to gauge theory. Based on supersymmetry we argue that the above truncation is not suited for conclusive tests of the BMN duality.Comment: 20 pages, 1 figur

    The open-charm radiative and pionic decays of molecular charmonium Y(4274)

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    In this work, we investigate the decay widths and the line shapes of the open-charm radiative and pionic decays of Y(4274) with the DsDˉs0(2317)D_s\bar{D}_{s0}(2317) molecular charmonium assignment. Our calculation indicates that the decay widths of Y(4274)→Ds+Ds∗−γY(4274)\to D^{+}_{s}D^{*-}_{s}\gamma and Y(4274)→Ds+Ds−π0Y(4274)\to D^+_{s}D^-_{s}\pi^0 can reach up to 0.05 keV and 0.75 keV, respectively. In addition, the result of the line shape of the photon spectrum of Y(4274)→Ds+Ds∗−γY(4274)\to D_s^+ {D}_s^{*-} \gamma shows that there exists a very sharp peak near the large end point of photon energy. The line shape of the pion spectrum of Y(4274)→Ds+Ds∗−π0Y(4274)\to D_s^+ {D}_s^{*-} \pi^0 is similar to that of the pion spectrum of Y(4274)→Ds+Ds∗−γY(4274)\to D_s^+ {D}_s^{*-} \gamma, where we also find a very sharp peak near the large end point of pion energy. According to our calculation, we suggest further experiments to carry out the search for the open-charm radiative and pionic decays of Y(4274).Comment: 7 pages, 6 figures, 1 table. Published versio

    1-- and 0++ heavy four-quark and molecule states in QCD

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    We estimate the masses of the 1^{--} heavy four-quark and molecule states by combining exponential Laplace (LSR) and finite energy (FESR) sum rules known perturbatively to lowest order (LO) in alpha_s but including non-perturbative terms up to the complete dimension-six condensate contributions. This approach allows to fix more precisely the value of the QCD continuum threshold (often taken ad hoc) at which the optimal result is extracted. We use double ratio of sum rules (DRSR) for determining the SU(3) breakings terms. We also study the effects of the heavy quark mass definitions on these LO results. The SU(3) mass-splittings of about (50 - 110) MeV and the ones of about (250 - 300) MeV between the lowest ground states and their 1st radial excitations are (almost) heavy-flavour independent. The mass predictions summarized in Table 4 are compared with the ones in the literature (when available) and with the three Y_c(4260,~4360,~4660) and Y_b(10890) 1^{--} experimental candidates. We conclude (to this order approximation) that the lowest observed state cannot be a pure 1^{--} four-quark nor a pure molecule but may result from their mixings. We extend the above analyzes to the 0^{++} four-quark and molecule states which are about (0.5-1) GeV heavier than the corresponding 1^{--} states, while the splittings between the 0^{++} lowest ground state and the 1st radial excitation is about (300-500) MeV. We complete the analysis by estimating the decay constants of the 1^{--} and 0^{++} four-quark states which are tiny and which exhibit a 1/M_Q behaviour. Our predictions can be further tested using some alternative non-perturbative approaches or/and at LHCb and some other hadron factories.Comment: 13 pages, 15 figures, 4 tables, version to appear in PLB (more general choice of the interpolating currents, estimate of the four-quark meson decay constants, new references added, slight numerical changes for the 0++ mass predictions

    Identification of plasma lipid biomarkers for prostate cancer by lipidomics and bioinformatics

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    Background: Lipids have critical functions in cellular energy storage, structure and signaling. Many individual lipid molecules have been associated with the evolution of prostate cancer; however, none of them has been approved to be used as a biomarker. The aim of this study is to identify lipid molecules from hundreds plasma apparent lipid species as biomarkers for diagnosis of prostate cancer. Methodology/Principal Findings: Using lipidomics, lipid profiling of 390 individual apparent lipid species was performed on 141 plasma samples from 105 patients with prostate cancer and 36 male controls. High throughput data generated from lipidomics were analyzed using bioinformatic and statistical methods. From 390 apparent lipid species, 35 species were demonstrated to have potential in differentiation of prostate cancer. Within the 35 species, 12 were identified as individual plasma lipid biomarkers for diagnosis of prostate cancer with a sensitivity above 80%, specificity above 50% and accuracy above 80%. Using top 15 of 35 potential biomarkers together increased predictive power dramatically in diagnosis of prostate cancer with a sensitivity of 93.6%, specificity of 90.1% and accuracy of 97.3%. Principal component analysis (PCA) and hierarchical clustering analysis (HCA) demonstrated that patient and control populations were visually separated by identified lipid biomarkers. RandomForest and 10-fold cross validation analyses demonstrated that the identified lipid biomarkers were able to predict unknown populations accurately, and this was not influenced by patient's age and race. Three out of 13 lipid classes, phosphatidylethanolamine (PE), ether-linked phosphatidylethanolamine (ePE) and ether-linked phosphatidylcholine (ePC) could be considered as biomarkers in diagnosis of prostate cancer. Conclusions/Significance: Using lipidomics and bioinformatic and statistical methods, we have identified a few out of hundreds plasma apparent lipid molecular species as biomarkers for diagnosis of prostate cancer with a high sensitivity, specificity and accuracy

    Spectroscopy of Mesons with Heavy Quarks

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    I will give a concise overview of mesons with heavy quarks including p-wave charmed mesons and charmonium (or charmonium-like) states such as X(3872), Y(4260), X(3940), Y(3940), Z(3930) etc. The effect from the nearby S-wave open channels on the quark model spectrum is emphasized.Comment: Plenary talk at INPC2007, http://inpc2007.riken.jp/P/P5-zhu.pd
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