1,191 research outputs found

    Association of LEP G2548A and LEPR Q223R Polymorphisms with Cancer Susceptibility: Evidence from a Meta-Analysis

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    __Background:__ Numerous epidemiological studies have examined associations of genetic variations in LEP (G2548A, -2548 nucleotide upstream of the ATG start site) and LEPR (Q223R, nonsynonymous SNP in exon 6) with cancer susceptibility; however, the findings are inconsistent. Therefore, we performed a meta-analysis to comprehensively evaluate such associations. __Methods:__ We searched published literature from MEDLINE, EMBASE, Web of Science and CBM for eligible publications. We also assessed genotype-based mRNA expression data from HapMap for rs7799039 (G2548A) and rs1137101 (Q223R) in normal cell lines derived from 270 subjects with different ethnicities. __Results:__ The final analysis included 16 published studies of 6569 cases and 8405 controls for the LEP G2548A and 19 studies of 7504 cases and 9581 controls for the LEPR Q223R. Overall, LEP G2548A was statistically significantly associated with an increased risk of overall cancer (AA vs. GG: OR=1.27, 95% CI=1.05-1.54; recessive model: OR=1.19, 9

    Measurement of the branching fractions of psi(2S) -> 3(pi+pi-) and J/psi -> 2(pi+pi-)

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    Using data samples collected at sqrt(s) = 3.686GeV and 3.650GeV by the BESII detector at the BEPC, the branching fraction of psi(2S) -> 3(pi+pi-) is measured to be [4.83 +- 0.38(stat) +- 0.69(syst)] x 10^-4, and the relative branching fraction of J/psi -> 2(pi+pi-) to that of J/psi -> mu+mu- is measured to be [5.86 +- 0.19(stat) +- 0.39(syst)]% via psi(2S) -> (pi+pi-)J/psi, J/psi -> 2(pi+pi-). The electromagnetic form factor of 3(pi+pi-) is determined to be 0.21 +- 0.02 and 0.20 +- 0.01 at sqrt(s) = 3.686GeV and 3.650GeV, respectively.Comment: 17pages, 7 figures, submitted to Phys. Rev.

    Observation of p pbar pi^0 and p pbar eta in psi' decays

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    The processes psi'-->p pbar pi^0 and psi'-->p pbar eta are studied using a sample of 14 million psi' decays collected with the Beijing Spectrometer at the Beijing Electron-Positron Collider. The branching fraction of psi'-->p pbar pi^0 is measured with improved precision as (13.2\pm 1.0\pm 1.5)\times 10^{-5}, and psi'-->p pbar eta is observed for the first time with a branching fraction of (5.8\pm 1.1\pm 0.7)\times 10^{-5}, where the first errors are statistical and the second ones are systematic.Comment: 15 pages, 8 figures and 3 table

    Measurements of J/psi decays into phi pi^0, phi eta, and phi eta^prime

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    Based on 5.8x10^7 J/psi events detected in BESII, the branching fractions of J/psi--> phi eta and phi eta^prime are measured for different eta and eta^prime decay modes. The results are significantly higher than previous measurements. An upper limit on B(J/psi--> phi pi^0) is also obtained.Comment: 9 pages, 10 figure

    Measurement of the chi_{c2} Polarization in psi(2S) to gamma chi_{c2}

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    The polarization of the chi_{c2} produced in psi(2S) decays into gamma chi_{c2} is measured using a sample of 14*10^6 psi(2S) events collected by BESII at the BEPC. A fit to the chi_{c2} production and decay angular distributions in psi(2S) to gamma chi_{c2}, chi_{c2} to pi pi and KK yields values x=A_1/A_0=2.08+/-0.44 and y=A_2/A_0=3.03 +/-0.66, with a correlation rho=0.92 between them, where A_{0,1,2} are the chi_{c2} helicity amplitudes. The measurement agrees with a pure E1 transition, and M2 and E3 contributions do not differ significantly from zero.Comment: 6 pages, 4 figures, 1 tabl

    Measurement of the final states ωπ0\omega \pi^0, ρη\rho \eta, and ρη\rho \eta^{'} from \psip electromagnetic decays and \ee annihilations

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    Cross sections and form factors for \ee \to \wpi, ρη\rho\eta, and \rho\etap at center of mass energies of 3.650, 3.686, and 3.773 GeV are measured using data samples collected with the BESII detector at the BEPC. Also, the branching fractions of \psi(2S) \rar \wpi, ρη\rho\eta, and \rho\etap are determined to be (1.870.62+0.68±0.28)×105(1.87^{+0.68}_{-0.62}\pm0.28)\times 10^{-5}, (1.780.62+0.67±0.17)×105(1.78^{+0.67}_{-0.62}\pm0.17)\times 10^{-5}, and (1.871.11+1.64±0.33)×105(1.87^{+1.64}_{-1.11}\pm0.33)\times10^{-5}, respectively.Comment: 8 pages, 4 figures, 4 table

    Partial Wave Analysis of χc0π+πK+K\chi_{c0}\to\pi^+\pi^-K^+K^-

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    A partial wave analysis of χc0π+πK+K\chi_{c0}\to\pi^+\pi^-K^+K^- in ψ(2S)γχc0\psi(2S)\to\gamma\chi_{c0} decay is presented using a sample of 14 million ψ(2S)\psi(2S) events accumulated by the BES II detector. The data are fitted to the sum of relativistic covariant tensor amplitudes for intermediate resonant decay modes. From the fit, significant contributions to χc0\chi_{c0} decays from the channels f0(980)f0(980)f_0(980)f_0(980), f0(980)f0(2200)f_0(980)f_0(2200), f0(1370)f0(1710)f_0(1370)f_0(1710), K(892)0Kˉ(892)0K^*(892)^0\bar K^*(892)^0, K0(1430)Kˉ0(1430)K^*_0(1430)\bar K^*_0(1430), K0(1430)Kˉ2(1430)+c.c.K^*_0(1430)\bar K^*_2(1430) + c.c., and K1(1270)KK_1(1270)K are found. Flavor-SU(3)-violating K1(1270)K1(1400)K_1(1270)-K_1(1400) asymmetry is observed. Values obtained for the masses and widths of the resonances f0(1710)f_0(1710), f0(2200)f_0(2200), f0(1370)f_0(1370), and K0(1430)K^*_0(1430) are presented.Comment: 16 pages, 9 figures, and 4 table

    Search for psi(3770)\ra\rho\pi at the BESII detector at the Beijing Electron-Positron Collider

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    Non-DDˉD\bar{D} decay \psppto \rhopi is searched for using a data sample of (17.3±0.5)pb1(17.3\pm 0.5) pb^{-1} taken at the center-of-mass energy of 3.773 GeV by the BESII detector at the BEPC. No \rhopi signal is observed, and the upper limit of the cross section is measured to be \sigma(\EETO \rhopi)<6.0 pb at 90% C. L. Considering the interference between the continuum amplitude and the \pspp resonance amplitude, the branching fraction of \pspp decays to ρπ\rho\pi is determined to be \BR(\pspp\ra\rho\pi)\in(6.0\times10^{-6}, 2.4\times10^{-3}) at 90% C. L. This is in agreement with the prediction of the SS- and DD-wave mixing scheme of the charmonium states for solving the ``\rhopi puzzle'' between \jpsi and \psp decays.Comment: 15 pages, 5 figure

    Measurements of the continuum RudsR_{\rm uds} and RR values in e+ee^+e^- annihilation in the energy region between 3.650 and 3.872 GeV

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    We report measurents of the continuum RudsR_{\rm uds} near the center-of-mass energy of 3.70 GeV, the Ruds(c)+ψ(3770)(s)R_{{\rm uds(c)}+\psi(3770)}(s) and the Rhad(s)R_{\rm had}(s) values in e+ee^+e^- annihilation at 68 energy points in the energy region between 3.650 and 3.872 GeV with the BES-II detector at the BEPC Collodier. We obtain the RudsR_{\rm uds} for the continuum light hadron (containing u, d and s quarks) production near the DDˉD\bar D threshold to be Ruds=2.141±0.025±0.085R_{\rm uds}=2.141 \pm 0.025 \pm 0.085.Comment: 5 pages, 3 figure

    Measurement of the cross section for e^+e^- -> ppbar at center-of-mass energies from 2.0 to 3.07 GeV

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    Cross sections for e^+e^- -> ppbar have been measured at 10 center-of-mass energies from 2.0 to 3.07 GeV by the BESII experiment at the BEPC, and proton electromagnetic form factors in the time-like region have been determined.Comment: 6 pages, 3 figure
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