200 research outputs found

    Partial Wave Analysis of J/Ïˆâ†’Îł(K+K−π+π−)J/\psi \to \gamma (K^+K^-\pi^+\pi^-)

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    BES data on J/Ïˆâ†’Îł(K+K−π+π−)J/\psi \to \gamma (K^+K^-\pi^+\pi^-) are presented. The K∗Kˉ∗K^*\bar K^* contribution peaks strongly near threshold. It is fitted with a broad 0−+0^{-+} resonance with mass M=1800±100M = 1800 \pm 100 MeV, width Γ=500±200\Gamma = 500 \pm 200 MeV. A broad 2++2^{++} resonance peaking at 2020 MeV is also required with width ∌500\sim 500 MeV. There is further evidence for a 2−+2^{-+} component peaking at 2.55 GeV. The non-K∗Kˉ∗K^*\bar K^* contribution is close to phase space; it peaks at 2.6 GeV and is very different from K∗K∗ˉK^{*}\bar{K^{*}}.Comment: 15 pages, 6 figures, 1 table, Submitted to PL

    Measurements of the Mass and Full-Width of the ηc\eta_c Meson

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    In a sample of 58 million J/ψJ/\psi events collected with the BES II detector, the process J/Ïˆâ†’ÎłÎ·c\psi\to\gamma\eta_c is observed in five different decay channels: ÎłK+K−π+π−\gamma K^+K^-\pi^+\pi^-, ÎłÏ€+π−π+π−\gamma\pi^+\pi^-\pi^+\pi^-, ÎłK±KS0π∓\gamma K^\pm K^0_S \pi^\mp (with KS0→π+π−K^0_S\to\pi^+\pi^-), ÎłÏ•Ï•\gamma \phi\phi (with ϕ→K+K−\phi\to K^+K^-) and Îłppˉ\gamma p\bar{p}. From a combined fit of all five channels, we determine the mass and full-width of ηc\eta_c to be mηc=2977.5±1.0(stat.)±1.2(syst.)m_{\eta_c}=2977.5\pm1.0 ({stat.})\pm1.2 ({syst.}) MeV/c2c^2 and Γηc=17.0±3.7(stat.)±7.4(syst.)\Gamma_{\eta_c} = 17.0\pm3.7 ({stat.})\pm7.4 ({syst.}) MeV/c2c^2.Comment: 9 pages, 2 figures and 4 table. Submitted to Phys. Lett.

    Measurements of ψ(2S)\psi(2S) decays into Vector- Tensor final states

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    Decays of the ψ(2S)\psi(2S) into vector plus tensor meson final states have been studied with 14 million ψ(2S)\psi(2S) events collected with the BESII detector. Branching fractions of \psi(2S) \rt \omega f_{2}(1270), ρa2(1320)\rho a_2(1320), K∗(892)0Kˉ2∗(1430)0+c.c.K^*(892)^0\bar{K}^*_2(1430)^0+c.c. and ϕf2â€Č(1525)\phi f_2^{\prime}(1525) are determined. They improve upon previous BESI results and confirm the violation of the "12%" rule for ψ(2S)\psi(2S) decays to VT channels with higher precision.Comment: 7 pages, 7 figures and 2 table

    Saikosaponins: a review of pharmacological effects.

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    Over the past decades, a number of phytochemicals have been reported to possess potent pharmacological effects. Saikosaponins represent a group of oleanane derivatives, usually as glucosides, which are commonly found in medicinal plants Bupleurum spp., which have been used as traditional Chinese medicine for more than 1,000 years in China. Emerging evidence suggests that saikosaponins have many pharmacological effects, including sedation, anticonvulsant, antipyretic, antiviral, immunity, anti-inflammation, antitumor properties, protecting liver and kidney and so on. The present review provides a comprehensive summary and analysis of the pharmacological properties of saikosaponins, supporting the potential uses of saikosaponins as a medicinal agent

    The effects of baicalein and baicalin on mitochondrial function and dynamics: A review

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    Mitochondria play an essential role in cell survival by providing energy, calcium buffering, and regulating apoptosis. A growing body of evidence shows that mitochondrial dysfunction and its consequences, including impairment of the mitochondrial respiratory chain, excessive generation of reactive oxygen species, and excitotoxicity, play a pivotal role in the pathogenesis of different diseases such as neurodegenerative diseases, neuropsychiatric disorders, and cancer. The therapeutical role of flavonoids on these diseases is gaining increasing acceptance. Numerous studies on experimental models have revealed the favorable role of flavonoids on mitochondrial function and structure. This review highlights the promising role of baicalin and its aglycone form, baicalein, on mitochondrial function and structure with a focus on its therapeutic effects. We also discuss their chemistry, sources and bioavailability

    Measurement of Branching Ratios for ηc\eta_c Hadronic Decays

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    In a sample of 58 million J/ψJ/\psi events collected with the BES II detector, the process J/Ïˆâ†’ÎłÎ·c\psi\to\gamma\eta_c is observed in five decay channels: ηc→K+K−π+π−\eta_c \to K^+K^-\pi^+\pi^-, π+π−π+π−\pi^+\pi^-\pi^+\pi^-, K±KS0π∓K^\pm K^0_S \pi^\mp (with KS0→π+π−K^0_S\to\pi^+\pi^-), ϕϕ\phi\phi (with ϕ→K+K−\phi\to K^+K^-) and ppˉp\bar{p}. From these signals, we determine Br(J/Ïˆâ†’ÎłÎ·c)×Br(ηc→K+K−π+π−)Br(J/\psi\to\gamma\eta_c)\times Br(\eta_c\to K^+K^-\pi^+\pi^-) =(1.5±0.2±0.2)×10−4=(1.5\pm0.2\pm0.2)\times10^{-4}, Br(J/Ïˆâ†’ÎłÎ·c)×Br(ηc→π+π−π+π−)Br(J/\psi\to\gamma\eta_c)\times Br(\eta_c\to \pi^+\pi^-\pi^+\pi^-) =(1.3±0.2±0.4)×10−4=(1.3\pm0.2\pm0.4)\times10^{-4}, Br(J/Ïˆâ†’ÎłÎ·c)×Br(ηc→K±KS0π∓)Br(J/\psi\to\gamma\eta_c)\times Br(\eta_c\to K^\pm K_{S}^{0}\pi^\mp) =(2.2±0.3±0.5)×10−4=(2.2\pm0.3\pm0.5)\times10^{-4}, Br(J/Ïˆâ†’ÎłÎ·c)×Br(ηc→ϕϕ)Br(J/\psi\to\gamma\eta_c)\times Br(\eta_c\to \phi\phi) =(3.3±0.6±0.6)×10−5=(3.3\pm0.6\pm0.6)\times10^{-5} and Br(J/Ïˆâ†’ÎłÎ·c)×Br(ηc→ppˉ)Br(J/\psi\to\gamma\eta_c)\times Br(\eta_c\to p\bar{p}) =(1.9±0.3±0.3)×10−5=(1.9\pm0.3\pm0.3)\times10^{-5}.Comment: 8 pages, 1 figures and 4 table. Submitted to Phys. Lett.

    Measurements of J/psi --> p \bar{p}

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    The process J/\psi --> p \bar{p} is studied using 57.7 X 10^6 J/\psi events collected with the BESII detector at the Beijing Electron Positron Collider. The branching ratio is determined to be Br(J/\psi --> p \bar{p})=(2.26 +- 0.01 +- 0.14) X 10^{-3}, and the angular distribution is well described by \frac{dN}{d cos\theta_p}=1+\alpha\cos^2\theta_p with \alpha = 0.676 +- 0.036 +- 0.042, where \theta_p is the angle between the proton and beam directions. The value of \alpha obtained is in good agreement with the predictions of first-order QCD.Comment: 6 pages, 2 figures, RevTex4, Submitted to Phys.Lett.

    Search for K_S K_S in J/psi and psi(2S) decays

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    The CP violating processes J/psi-->K_S K_S and psi(2S)-->K_S K_S are searched for using samples of 58 million J/psi and 14 million psi(2S) events collected with the Beijing Spectrometer at the Beijing Electron Positron Collider. No signal is observed, and upper limits on the decay branching ratios are determined to be BR(J/psi-->K_S K_S) K_S K_S) < 4.6x10^{-6} at the 95% confidence level.Comment: 6 pages, 4 figures, submitted to Phys. Lett.
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