1,795 research outputs found

    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

    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

    Experimental study of ψ(2S)\psi(2S) decays to \K^+ K^- \pi^+ \pi^- \pi^0 final states

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    K+Kπ+ππ0K^+K^-\pi^+\pi^-\pi^0 final states are studied using a sample of 14×10614\times10^6 ψ(2S)\psi(2S) decays collected with the Beijing Spectrometer (BESII) at the Beijing Electron-Position Collider. The branching fractions of ψ(2S)\psi(2S) decays to K+Kπ+ππ0 K^+K^-\pi^+\pi^-\pi^0, ωK+K\omega K^+ K^-, ωf0(1710)\omega f_0(1710), K(892)0Kπ+π0+c.c. K^{\ast}(892)^0 K^- \pi^+\pi^0+c.c., K(892)+Kπ+π+c.c.K^{\ast}(892)^{+} K^- \pi^+\pi^- +c.c., K(892)+Kρ0+c.c.K^{\ast}(892)^{+} K^- \rho^0+c.c. and K(892)0Kρ++c.c.K^{\ast}(892)^0 K^-\rho^+ + c.c. are determined. The first two agree with previous measurements, and the last five are first measurements.Comment: 19 pages, 9 figure

    Measurement of \psip Radiative Decays

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    Using 14 million psi(2S) events accumulated at the BESII detector, we report first measurements of branching fractions or upper limits for psi(2S) decays into gamma ppbar, gamma 2(pi^+pi^-), gamma K_s K^-pi^++c.c., gamma K^+ K^- pi^+pi^-, gamma K^{*0} K^- pi^+ +c.c., gamma K^{*0}\bar K^{*0}, gamma pi^+pi^- p pbar, gamma 2(K^+K^-), gamma 3(pi^+pi^-), and gamma 2(pi^+pi^-)K^+K^- with the invariant mass of hadrons below 2.9GeV/c^2. We also report branching fractions of psi(2S) decays into 2(pi^+pi^-) pi^0, omega pi^+pi^-, omega f_2(1270), b_1^\pm pi^\mp, and pi^0 2(pi^+pi^-) K^+K^-.Comment: 5 pages, 4 figure

    Measurements of J/ψJ/\psi and ψ(2S)\psi(2S) decays into ΛΛˉπ0\Lambda \bar{\Lambda}\pi^0 and ΛΛˉη\Lambda \bar{\Lambda}\eta

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    Using 58 million J/ψJ/\psi and 14 million ψ(2S)\psi(2S) events collected by the BESII detector at the BEPC, branching fractions or upper limits for the decays J/ψJ/\psi and ψ(2S)ΛΛˉπ0\psi(2S) \to \Lambda \bar{\Lambda}\pi^0 and ΛΛˉη\Lambda \bar{\Lambda}\eta are measured. For the isospin violating decays, the upper limits are determined to be B(J/ψΛΛˉπ0)<6.4×105{\cal B}(J/\psi \to \Lambda \bar{\Lambda}\pi^0)<6.4\times 10^{-5} and B(ψ(2S)ΛΛˉπ0)<4.9×105{\cal B}(\psi(2S) \to \Lambda \bar{\Lambda}\pi^0)<4.9\times 10^{-5} at the 90% confidence level. The isospin conserving process J/ψΛΛˉηJ/\psi \to \Lambda \bar{\Lambda}\eta is observed for the first time, and its branching fraction is measured to be B(J/ψΛΛˉη)=(2.62±0.60±0.44)×104{\cal B}(J/\psi \to \Lambda \bar{\Lambda}\eta)=(2.62\pm 0.60\pm 0.44)\times 10^{-4}, where the first error is statistical and the second one is systematic. No ΛΛˉη\Lambda \bar{\Lambda}\eta signal is observed in ψ(2S)\psi(2S) decays, and B(ψ(2S)ΛΛˉη)<1.2×104{\cal B}(\psi(2S) \to \Lambda \bar{\Lambda}\eta)<1.2\times 10^{-4} is set at the 90% confidence level. Branching fractions of J/ψJ/\psi decays into Σ+πbarΛ\Sigma^+ \pi^- bar{\Lambda} and Σˉπ+Λ\bar{\Sigma}^- \pi^+ \Lambda are also reported, and the sum of these branching fractions is determined to be B(J/ψΣ+πΛˉ+c.c.)=(1.52±0.08±0.16)×103{\cal B}(J/\psi \to \Sigma^+\pi^- \bar{\Lambda} + c.c.)=(1.52\pm 0.08\pm 0.16)\times 10^{-3}.Comment: 7 pages, 10 figures. Phys.Rev.D comments considere

    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

    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

    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
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