820 research outputs found

    QCD corrections to Upsilon production via color-octet states at the Tevatron and LHC

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    The NLO QCD corrections to Upsilon production via S-wave color-octet states Upsilon(^1S_0^8,^3S_1^8) at the Tevatron and LHC is calculated. The K factors of total cross section (ratio of NLO to LO) are 1.313 and 1.379 for Upsilon(^1S_0^8) and Upsilon(^3S_1^8) at the Tevatron, while at the LHC they are 1.044 and 1.182, respectively. By fitting the experimental data from the D0, the matrix elements for S-wave color-octet states are obtained. And new predictions for Upsilon production are presented. The prediction for the polarization of inclusive Upsilon contains large uncertainty rising from the polarization of Upsilon from feed-down of chi_b. To further clarify the situation, new measurements on the production and polarization for direct Upsilon are expected.Comment: 13 pages, 10 Figure

    Arsenic trioxide treatment of rabbit liver VX-2 carcinoma via hepatic arterial cannulationinduced apoptosis and decreased levels of survivin in the tumor tissue

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    Aim To investigate the role of tumor apoptosis-inhibitory protein survivin in arsenic trioxide-induced apoptosis in VX-2 carcinoma in the rabbit liver by means of transcatheter arterial chemoembolization. Methods Sixteen rabbits with 32 implanted hepatic VX-2 tumors were randomly divided into two groups. The experimental group received 2 mg of arsenic trioxide and 1 mL of ultra-fluid lipiodol co-injected via hepatic arterial cannulation and the control group received only 1 mL of lipiodol. Animals were sacrificed 3 weeks after trans-catheterial arterial chemoembolization. Tumor tissue and tumor- peripheral tissue were collected for analysis. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling staining was used to assess tumor cells apoptosis. Immunohistochemistry was used to assess the presence of survivin protein. Reverse transcription polymerase chain reaction was used to determine the expression of survivin gene. Results The number of apoptotic cells significantly increased in the tumor tissue (5.20 ± 0.60%) compared to tumor-peripheral tissue (1.29 ± 0.42%) of the arsenic trioxide- treated group. Survivin expression levels in the tumor tissue were significantly reduced in arsenic trioxidetreated group (7.68 ± 0.65) compared to the control group (35.30 ± 4.63). Conclusion Transcatheter arterial chemoembolization with arsenic trioxide induced apoptosis of VX-2 carcinoma, in which tumor apoptosis-inhibitory protein survivin may have played a role

    Inversion formula of multifractal energy dissipation in 3D fully developed turbulence

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    The concept of inverse statistics in turbulence has attracted much attention in the recent years. It is argued that the scaling exponents of the direct structure functions and the inverse structure functions satisfy an inversion formula. This proposition has already been verified by numerical data using the shell model. However, no direct evidence was reported for experimental three dimensional turbulence. We propose to test the inversion formula using experimental data of three dimensional fully developed turbulence by considering the energy dissipation rates in stead of the usual efforts on the structure functions. The moments of the exit distances are shown to exhibit nice multifractality. The inversion formula between the direct and inverse exponents is then verified.Comment: 3 RevTex pages including 3 eps figure

    Low-energy Scattering of (DDˉ)±(D^{*}\bar{D}^{*})^\pm System and the Resonance-like Structure Zc(4025)Z_c(4025)

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    In this paper, low-energy scattering of the (DDˉ)±(D^{*}\bar{D}^{*})^\pm meson system is studied within L\"uscher's finite-size formalism using Nf=2N_{f}=2 twisted mass gauge field configurations. With three different pion mass values, the ss-wave threshold scattering parameters, namely the scattering length a0a_0 and the effective range r0r_0, are extracted in JP=1+J^P=1^+ channel. Our results indicate that, in this particular channel, the interaction between the two vector charmed mesons is weakly repulsive in nature hence do not support the possibility of a shallow bound state for the two mesons, at least for the pion mass values being studied. This study provides some useful information on the nature of the newly discovered resonance-like structure Zc(4025)Z_c(4025) observed in various experiments.Comment: 11 pages, 6 figures. arXiv admin note: substantial text overlap with arXiv:1403.131

    A Lattice Study of (Dˉ1D)±(\bar{D}_1 D^{*})^\pm Near-threshold Scattering

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    In this exploratory lattice study, low-energy near threshold scattering of the (Dˉ1D)±(\bar{D}_1 D^{*})^\pm meson system is analyzed using lattice QCD with Nf=2N_f=2 twisted mass fermion configurations. Both s-wave (JP=0J^P=0^-) and p-wave (JP=1+J^P=1^+) channels are investigated. It is found that the interaction between the two charmed mesons is attractive near the threshold in both channels. This calculation provides some hints in the searching of resonances or bound states around the threshold of (Dˉ1D)±(\bar{D}_1 D^{*})^\pm system.Comment: 20 pages, 15 figures, matches the version on PR

    Two Photon Decays of ηc\eta_c from Lattice QCD

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    We present an exploratory lattice study for the two-photon decay of ηc\eta_c using Nf=2N_f=2 twisted mass lattice QCD gauge configurations generated by the European Twisted Mass Collaboration. Two different lattice spacings of a=0.067a=0.067fm and a=0.085a=0.085fm are used in the study, both of which are of physical size of 2fmfm. The decay widths are found to be 1.025(5)1.025(5)KeV for the coarser lattice and 1.062(5)1.062(5)KeV for the finer lattice respectively where the errors are purely statistical. A naive extrapolation towards the continuum limit yields Γ1.122(14)\Gamma\simeq 1.122(14)KeV which is smaller than the previous quenched result and most of the current experimental results. Possible reasons are discussed.Comment: 13 pages, 7 figures; matches the published versio
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