763 research outputs found

    Measurements of branching fractions for inclusive K0~/K0 and K*(892)+- decays of neutral and charged D mesons

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    Using the data sample of about 33 pb-1 collected at and around 3.773 GeV with the BES-II detector at the BEPC collider, we have studied inclusive K0~/K0 and K*(892)+- decays of D0 and D+ mesons. The branching fractions for the inclusive K0~/K0 and K*(892)- decays are measured to be BF(D0 to K0~/K0 X)=(47.6+-4.8+-3.0)%, BF(D+ to K0~/K0 X)=(60.5+-5.5+-3.3)%, BF(D0 to K*- X)=(15.3+- 8.3+- 1.9)% and BF(D+ to K*- X)=(5.7+- 5.2+- 0.7)%. The upper limits of the branching fractions for the inclusive K*(892)+ decays are set to be BF(D0 to K*+ X)<3.6% and BF(D+ to K*+ X) <20.3% at 90% confidence level

    Direct Measurements of the Branching Fractions for Inclusive K±K^\pm and Inclusive Semileptonic Decays of D+D^+ and D0D^0 Mesons

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    With singly-tagged Dˉ\bar D samples selected from the data collected at and around 3.773 GeV with the BESII detector at the BEPC collider, we have measured the branching fractions for the inclusive K±K^\pm decays of D+D^+ and D0D^0 mesons, which are BF(D+KX)=(24.7±1.3±1.2)BF(D^+\to K^-X) = (24.7 \pm 1.3 \pm 1.2)%, BF(D+K+X)=(6.1±0.9±0.4)BF(D^+\to K^+X) = (6.1 \pm 0.9 \pm 0.4) %, BF(D0KX)=(57.8±1.6±3.2)BF(D^0\to K^-X) = (57.8 \pm 1.6 \pm 3.2) % and BF(D0K+X)=(3.5±0.7±0.3)BF(D^0\to K^+X) = (3.5 \pm 0.7 \pm 0.3) %, respectively. We have also measured the branching fractions for the inclusive semileptonic decays of D+D^+ and D0D^0 mesons to be BF(D+e+X)=(15.2±0.9±0.8)BF(D^+ \to e^+ X)=(15.2 \pm 0.9 \pm 0.8)% and BF(D0e+X)=(6.3±0.7±0.4)BF(D^0 \to e^+ X) =(6.3 \pm 0.7 \pm 0.4) %. These yield the ratio of their partial widths to be Γ(D+e+X)/Γ(D0e+X)=0.95±0.12±0.07\Gamma(D^+ \to e^+X)/\Gamma(D^0 \to e^+X)=0.95 \pm 0.12 \pm 0.07.Comment: 6 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

    First observation of ψ(2S)pnˉπ+c.c.\psi(2S) \to p \bar{n} \pi^- +c.c.

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    Using 14 million ψ(2S)\psi(2S) events collected with the Beijing Spectrometer (BESII) at the Beijing Electron-Positron Collider, the branching fractions of ψ(2S)\psi(2S) decays to pnˉπp \bar{n} \pi^- and pˉnπ+\bar{p} n \pi^+ and the branching fractions of the main background channels ψ(2S)pnˉππ0\psi(2S) \to p \bar{n} \pi^-\pi^0, ψ(2S)γχc0γpnˉπ\psi(2S) \to \gamma\chi_{c0} \to \gamma p \bar{n} \pi^-, ψ(2S)γχc2γpnˉπ\psi(2S) \to \gamma\chi_{c2} \to \gamma p \bar{n} \pi^-, and ψ(2S)γχcJγpnˉππ0\psi(2S) \to \gamma \chi_{cJ} \to \gamma p \bar{n} \pi^- \pi^0 are determined. The contributions of the NN^{\ast} resonances in ψ(2S)pnˉπ+c.c.\psi(2S) \to p \bar{n} \pi^- +c.c. are also discussed.Comment: 19 pages, 8 figures, add vertex requirement systematic erro

    Observation of a near-threshold enhancement in the \omega\phi mass spectrum from the doubly OZI suppressed decay J/\psi \to \gamma \omega \phi

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    An enhancement near threshold is observed in the \omega \phi invariant mass spectrum from the doubly OZI suppressed decays of J/\psi \to \gamma \omega \phi, based on a sample of 5.8 X 10^7 J/\psi events collected with the BESII detector. A partial wave analysis shows that this enhancement favors J^P = 0^+, and its mass and width are M = 1812^{+19}_{-26} (stat) +- 18 (syst) MeV/c^2 and \Gamma = 105+-20 (stat) +- 28(syst)MeV/c2.TheproductbranchingfractionisdeterminedtobeB(J/ψγX)B(Xωϕ)=(2.61+0.27(stat)+0.65 (syst) MeV/c^2. The product branching fraction is determined to be B(J/\psi\to \gamma X) B(X\to\omega\phi) = (2.61 +- 0.27 (stat) +- 0.65 (syst)) X 10^{-4}.Comment: Accepted by PRL, the version to be appeared in PR

    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

    Genome-wide regulation of innate immunity by juvenile hormone and 20-hydroxyecdysone in the Bombyx fat body

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    <p>Abstract</p> <p>Background</p> <p>Insect innate immunity can be affected by juvenile hormone (JH) and 20-hydroxyecdysone (20E), but how innate immunity is developmentally regulated by these two hormones in insects has not yet been elucidated. In the silkworm, <it>Bombyx mori</it>, JH and 20E levels are high during the final larval molt (4 M) but absent during the feeding stage of 5<sup>th </sup>instar (5 F), while JH level is low and 20E level is high during the prepupal stage (PP). Fat body produces humoral response molecules and hence is considered as the major organ involved in innate immunity.</p> <p>Results</p> <p>A genome-wide microarray analysis of <it>Bombyx </it>fat body isolated from 4 M, 5 F and PP uncovered a large number of differentially-expressed genes. Most notably, 6 antimicrobial peptide (AMP) genes were up-regulated at 4 M versus PP suggesting that <it>Bombyx </it>innate immunity is developmentally regulated by the two hormones. First, JH treatment dramatically increased AMP mRNA levels and activities. Furthermore, 20E treatment exhibited inhibitory effects on AMP mRNA levels and activities, and RNA interference of the 20E receptor <it>EcR</it>-<it>USP </it>had the opposite effects to 20E treatment.</p> <p>Conclusion</p> <p>Taken together, we demonstrate that JH acts as an immune-activator while 20E inhibits innate immunity in the fat body during <it>Bombyx </it>postembryonic development.</p

    Investigation on viscosity and non-isothermal crystallization behavior of P-bearing steelmaking slags with varying TiO2 content

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    The viscous flow and crystallization behavior of CaO-SiO2-MgO-Al2O3-FetO-P2O5-TiO2 steelmaking slags have been investigated over a wide range of temperatures under Ar (High purity, >99.999 pct) atmosphere, and the relationship between viscosity and structure was determined. The results indicated that the viscosity of the slags slightly decreased with increasing TiO2 content. The constructed nonisothermal continuous cooling transformation (CCT) diagrams revealed that the addition of TiO2 lowered the crystallization temperature. This can mainly be ascribed to that addition of TiO2 promotes the formation of [TiO6]-octahedra units and, consequently, the formation of MgFe2O4-Mg2TiO4 solid solution. Moreover, the decreasing viscosity has a significant effect on enhancing the diffusion of ion units, such as Ca2+ and [TiO4]-tetrahedra, from bulk melts to the crystal–melt interface. The crystallization of CaTiO3 and CaSiTiO5 was consequently accelerated, which can improve the phosphorus content in P-enriched phase (n2CaO·SiO2-3CaO·P2O5). Finally, the nonisothermal crystallization kinetics was characterized and the activation energy for the primary crystal growth was derived such that the activation energy increases from −265.93 to −185.41 KJ·mol−1 with the addition of TiO2 content, suggesting that TiO2 lowered the tendency for the slags to crystallize
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