اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMeasurement of the branching ratios $psi^prime to e^+ e^-$, $psi^prime to J/psi pi pi$ and $psi^prime to J/psi eta$
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We have measured several branching ratios for $psi^prime$ decay using the data collected by FNAL E835 experiment during year 2000, obtaining ${cal B}(psi^prime to e^+ e^-) = 0.0068pm0.0001pm0.0004$, ${cal B}(psi^prime to J/psi pi^+ pi^-) = 0.292pm0.005pm0.018$, ${cal B}(psi^prime to J/psi pi^0 pi^0) = 0.167pm0.005pm0.014$ and ${cal B}(psi^prime to J/psi eta) = 0.028pm0.002pm0.002$. We also present a measurement of the dipion mass distribution in the decays $psi^prime to J/psi pi pi$.
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Using the data samples of $1.31times 10^9$ $J/psi$ events and $4.48times 10^8$ $psi(3686)$ events collected with the BESIII detector, partial wave analyses on the decays $J/psi$ and $psi(3686) to pi^+pi^-eta^prime$ are performed with a relativistic c
ovariant tensor amplitude approach. The dominant contribution is found to be $J/psi$ and $psi(3686)$ decays to $rhoeta^prime$. In the $J/psi$ decay, the branching fraction ${cal B}(J/psito rhoeta^prime)$ is determined to be $(7.90pm0.19(mathrm{stat})pm0.49(mathrm{sys}))times 10^{-5}$. Two solutions are found in the $psi(3686)$ decay, and the corresponding branching fraction ${cal B}(psi(3686)to rhoeta^prime)$ is $(1.02pm0.11(mathrm{stat})pm0.24(mathrm{sys}))times 10^{-5}$ for the case of constructive interference, and $(5.69pm1.28(mathrm{stat})pm2.36(mathrm{sys}))times 10^{-6}$ for destructive interference. As a consequence, the ratios of branching fractions between $psi(3686)$ and $J/psi$ decays to $rhoeta^prime$ are calculated to be $(12.9pm1.4(mathrm{stat})pm3.1(mathrm{sys}))$% and $(7.2pm1.6(mathrm{stat})pm3.0(mathrm{sys}))$%, respectively. We also determine the inclusive branching fractions of $J/psi$ and $psi(3686)$ decays to $pi^+pi^-eta^prime$ to be $(1.36pm0.02(mathrm{stat})pm0.08(mathrm{sys}))times 10^{-4}$ and $(1.51pm0.14(mathrm{stat})pm 0.23(mathrm{sys}))times 10^{-5}$, respectively.
We observe the process $psi(3686) to p bar{p} eta^{prime}$ for the first time, with a statistical significance higher than 10$sigma$, and measure the branching fraction of $J/psi to p bar{p} eta^{prime}$ with an improved accuracy compared to earlier
studies. The measurements are based on $4.48 times 10^8$ $psi(3686)$ and $1.31 times 10^{9}$ $J/psi$ events collected by the BESIII detector operating at the BEPCII. The branching fractions are determined to be $B(psi(3686) to p bar{p} eta^{prime}) = (1.10pm0.10pm0.08)times10^{-5}$ and $B(J/psi to p bar{p} eta^{prime})=(1.26pm0.02pm 0.07)times10^{-4}$, where the first uncertainties are statistical and the second ones systematic. Additionally, the $eta-eta^{prime}$ mixing angle is determined to be $-24^{circ} pm 11^{circ}$ based on $psi(3686) to p bar{p} eta^{prime}$, and $-24^{circ} pm 9^{circ}$ based on $J/psi to p bar{p} eta^{prime}$, respectively.
The products of the electron width of the J/psi meson and the branching fraction of its decays to the lepton pairs were measured using data from the KEDR experiment at the VEPP-4M electron-positron collider. The results are Gamma_{ee}(J/psi)*Br(J/p
si->e^+e^-)=(0.3323pm0.0064pm0.0048) keV, Gamma_{ee}(J/psi)*Br(J/psi->mu^+mu^-)=(0.3318pm0.0052pm0.0063) keV. Their combinations Gamma_{ee}times(Gamma_{ee}+Gamma_{mumu})/Gamma=(0.6641pm0.0082pm0.0100) keV, Gamma_{ee}/Gamma_{mumu}=1.002pm0.021pm0.013 can be used to improve theaccuracy of the leptonic and full widths and test leptonic universality. Assuming emu universality and using the world average value of the lepton branching fraction, we also determine the leptonic Gamma_{ll}=5.59pm0.12 keV and total Gamma=94.1pm2.7 keV widths of the J/psi meson.
Using $1.31 times 10^9$ $J/psi$ events collected by the BESIII detector at the BEPCII $e^+e^-$ collider, we report the first observation of the $h_1(1380)$ in $J/psi to eta^{prime} h_1(1380)$ with a significance of more than ten standard deviations.
The mass and width of the possible axial-vector strangeonium candidate $h_1(1380)$ are measured to be $M = (1423.2 pm 2.1 pm 7.3)mevcc$ and $Gamma = (90.3 pm 9.8 pm 17.5)mev$. The product branching fractions, assuming no interference, are determined to be $mathcal{B}(J/psi to eta^{prime}h_1(1380)) times mathcal{B}(h_1(1380) to K^{*}(892)^{+} K^{-} +c.c.) = (1.51 pm 0.09 pm 0.21) times 10^{-4}$ in $eta^{prime}K^+K^-pi^0$ mode and $mathcal{B}(J/psi to eta^{prime}h_1(1380)) times mathcal{B}(h_1(1380) to K^{*}(892)bar K +c.c.) = (2.16 pm 0.12 pm 0.29) times 10^{-4}$ in $eta^{prime}K_S^0K^{pm}pi^{mp}$ mode. The first uncertainties are statistical and the second are systematic. Isospin symmetry violation is observed in the decays $h_1(1380) to K^{*}(892)^{+} K^{-} +c.c.$ and $h_1(1380) to K^{*}(892)^{0}bar K^{0} +c.c.$. Based on the measured $h_1(1380)$ mass, the mixing angle between the states $h_1(1170)$ and $h_1(1380)$ is determined to be $(35.9pm2.6)^{circ}$, consistent with theoretical expectations.
We study the decays of the J/psi and psi mesons to pi+pi-pi0 using data samples at both resonances collected with the BES III detector in 2009. We measure the corresponding branching fractions with unprecedented precision and provide mass spectra and
Dalitz plots. The branching fraction for J/psi -> pi+pi-pi0 is determined to be (2.137 +- 0.004 (stat.) +0.058-0.056 (syst.) +0.027-0.026 (norm.))*10-2, and the branching fraction for psi -> pi+pi-pi0 is measured as (2.14 +- 0.03 (stat.) +0.08-0.07 (syst.) +0.09-0.08 (norm.))*10-4. The J/psi decay is found to be dominated by an intermediate rho(770) state, whereas the psi decay is dominated by di-pion masses around 2.2 GeV/c2, leading to strikingly different Dalitz distributions.
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