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Register a new userStudy of $psi(3686)topi^0 h_c, h_ctogammaeta_c$ via $eta_c$ exclusive decays
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The process $psi(3686) to pi^0 h_c, h_c to gamma eta_c$ has been studied with a data sample of $106 pm 4$ million $psi(3686)$ events collected with the BESIII detector at the BEPCII storage ring. The mass and width of the $P$-wave charmonium spin-singlet state $h_c(^1P_1)$ are determined by simultaneously fitting distributions of the $pi^0$ recoil mass for 16 exclusive $eta_c$ decay modes. The results, $M(hc) = 3525.31 pm 0.11 {rm (stat.)} pm 0.14 {rm (syst.)}$,MeV/$c^2$ and $Gamma(hc) = 0.70 pm 0.28 pm 0.22$,MeV, are consistent with and more precise than previous measurements. We also determine the branching ratios for the 16 exclusive $eta_c$ decay modes, five of which have not been measured previously. New measurements of the $eta_c$ line-shape parameters in the $E1$ transition $h_ctogammaeta_c$ are made by selecting candidates in the $h_c$ signal sample and simultaneously fitting the hadronic mass spectra for the 16 $eta_c$ decay channels. The resulting $eta_c$ mass and width values are $M(eta_c) = 2984.49 pm 1.16 pm 0.52$,MeV/$c^2$ and $Gamma(eta_c) = 36.4 pm 3.2 pm 1.7$,MeV.
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We study the decays of $J/psi$ and $psi(3686)$ to the final states $Sigma(1385)^{0}barSigma(1385)^{0}$ and $Xi^0barXi^{0}$ based on a single baryon tag method using data samples of $(1310.6 pm 7.0) times 10^{6}$ $J/psi$ and $(447.9 pm 2.9) times 10^{6}$ $psi(3686)$ events collected with the BESIII detector at the BEPCII collider. The decays to $Sigma(1385)^{0}barSigma(1385)^{0}$ are observed for the first time. The measured branching fractions of $J/psi$ and $psi(3686)rightarrowXi^0barXi^{0}$ are in good agreement with, and much more precise, than the previously published results. The angular parameters for these decays are also measured for the first time. The measured angular decay parameter for $J/psirightarrowSigma(1385)^{0}barSigma(1385)^{0}$, $alpha =-0.64 pm 0.03 pm 0.10$, is found to be negative, different to the other decay processes in this measurement. In addition, the 12% rule and isospin symmetry in the $J/psi$ and $psi(3686)rightarrowXibarXi$ and $Sigma(1385)bar{Sigma}(1385)$ systems are tested.
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 covariant 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.
Based on the data sample of $448.1times10^{6}$ $psi(3686)$ events collected with the BESIII detector at BEPCII, we present a study of the decays $psi(3686)rightarrowgammachi_{cJ}rightarrowgammabar{p}K^{*+}Lambda+c.c.$ and $psi(3686)rightarrowbar{p}K^{*+}Lambda+c.c.$. The branching fractions of $chi_{cJ}rightarrowbar{p}K^{*+}Lambda+c.c.$ ($J$=0, 1, 2) are measured to be $(4.8pm0.7pm0.5)times10^{-4}$, $(5.0pm0.5pm0.4)times10^{-4}$, and $(8.2pm0.9pm0.7)times10^{-4}$, respectively, where the first uncertainties are statistical and the second systematic. The branching fraction of $psi(3686)rightarrowbar{p}K^{*+}Lambda+c.c.$ is measured to be $(6.3pm0.5pm0.5)times10^{-5}$. All these decay modes are observed for the first time.
Using the data samples of $(1310.6pm7.2 )times 10^{6}$ $J/psi$ events and $(448.1pm2.9)times 10^{6}$ $psi(3686)$ events collected with the BESIII detector, we search for the rare decays $J/psi to D^{0} e^{+}e^{-} +c.c.$ and $psi(3686) to D^{0} e^{+}e^{-} +c.c.$. No significant signals are observed and the corresponding upper limits on the branching fractions at the $90%$ confidence level are determined to be $Br(J/psi to D^{0} e^{+}e^{-} +c.c.)< 8.5times 10^{-8}$ and $Br (psi(3686) to D^{0} e^{+}e^{-} +c.c.)<1.4times 10^{-7}$, respectively. Our limit on $Br(J/psi to D^{0} e^{+}e^{-} +c.c.)$ is more stringent by two orders of magnitude than the previous results, and the $Br(psi(3686) to D^{0} e^{+}e^{-} +c.c.)$ is measured for the first time.
Using $1310.6times10^6$ $J/psi$ and $447.9times10^6$ $psi(3686)$ events collected with the BESIII detector at the BEPCII $e^{+}e^{-}$ collider, the branching fractions and the angular distributions of $J/psi$ and $psi(3686)$ decays to $Lambdabar{Lambda}$ and $Sigma^0bar{Sigma}^0$ final states are measured. The branching fractions are in agreement with, and much more precise than, the averages of previously published results. The polar angular distributions of $psi(3686)$ decays are measured for the first time, while those of $J/psi$ decays are measured with much improved precision. In addition, the ratios of branching fractions $frac{mathcal{B}(psi(3686)toLambdabar{Lambda})}{mathcal{B}(J/psitoLambdabar{Lambda})}$ and $frac{mathcal{B}(psi(3686)toSigma^0bar{Sigma}^0)}{mathcal{B}(J/psitoSigma^0bar{Sigma}^0)}$ are determined to test the 12% rule.
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