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Register a new userMeasurement of Branching Fractions of $J/psi$ and $psi(3686)$ decays to $Sigma^{+}$ and $overline{Sigma}^-$
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Using $1310.6times10^{6}$ $J/psi$ and $448.1times10^{6}$ $psi(3686)$ events collected with the BESIII detector, the branching fractions of $J/psi$ and $psi(3686)$ decays to $Sigma^{+}overline{Sigma}^{-}$ are measured to be $(10.61 pm 0.04 pm 0.36) times 10^{-4}$ and $(2.52 pm 0.04 pm 0.09) times 10^{-4}$, respectively. In addition, the ratio of $mathcal{B}(psi(3686) rightarrow Sigma^{+}overline{Sigma}^{-})/mathcal{B}(J/psi rightarrow Sigma^{+}overline{Sigma}^{-})$ is determined to be $(23.8 pm 1.1)%$ which violates the $12%$ rule.
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From $1310.6times10^{6}$ $J/psi$ and $448.1times10^{6}$ $psi(3686)$ events collected with the BESIII experiment, we report the first observation of $Sigma^{+}$ and $bar{Sigma}^{-}$ spin polarization in $e^+e^-rightarrow J/psi (psi(3686)) rightarrow Sigma^{+} bar{Sigma}^{-}$ decays. The relative phases of the form factors $DeltaPhi$ have been measured to be $(-15.5pm0.7pm0.5)^{circ}$ and $(21.7pm4.0pm0.8)^{circ}$ with $J/psi$ and $psi(3686)$ data, respectively. The non-zero value of $DeltaPhi$ allows for a direct and simultaneous measurement of the decay asymmetry parameters of $Sigma^{+}rightarrow p pi^{0}~(alpha_0 = -0.998pm0.037pm0.009)$ and $bar{Sigma}^{-}rightarrow bar{p} pi^{0}~(bar{alpha}_0 = 0.990pm0.037pm0.011)$, the latter value being determined for the first time. The average decay asymmetry, $(alpha_{0} - bar{alpha}_{0})/2$, is calculated to be $-0.994pm0.004pm0.002$. The CP asymmetry $A_{rm CP,Sigma} = (alpha_0 + bar{alpha}_0)/(alpha_0 - bar{alpha}_0) = -0.004pm0.037pm0.010$ is extracted for the first time, and is found to be consistent with CP conservation.
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.
Using a data sample of $448times10^{6}$ $psi(3686)$ events collected with the BESIII detector operating at the BEPCII storage ring, the decays $psi(3686)rightarrowgammaeta$ and $psi(3686)rightarrowgammapi^{0}$ are observed with a statistical significance of $7.3sigma$ and $ 6.7sigma$, respectively. The branching fractions are measured to be $mathcal{B}(psi(3686)rightarrowgammaeta)=(0.85pm0.18pm0.05)times10^{-6}$ and $mathcal{B}(psi(3686)rightarrowgammapi^{0})=(0.95pm0.16pm0.05)times10^{-6}$. In addition, we measure the branching fraction of $psi(3686)rightarrowgammaeta$ to be $mathcal{B}(psi(3686)rightarrowgammaeta)=(125.1pm2.2pm6.2)times 10^{-6}$, with improved precision compared to previous results.
Based on $4.481times10^8$ $psi(3686)$ events collected with the BESIII detector at BEPCII, the branching fraction of the isospin violating decay $psi(3686)rightarrowbar{Sigma}^{0}Lambda+c.c.$ is measured to be $(1.60 pm 0.31 pm 0.13~pm~0.58) times 10^{-6}$, where the first uncertainty is statistical, the second is systematic, and the third is the uncertainty arising from interference with the continuum. This result is significantly smaller than the measurement based on CLEO-c data sets. The decays $chi_{cJ} rightarrowLambdabar{Lambda}$ are measured via $psi(3686)rightarrowgammachi_{cJ}$, and the branching fractions are determined to be $mathcal{B}left(chi_{c0}rightarrowLambdabar{Lambda}right)=(3.64 pm 0.10 pm 0.10 pm 0.07)times 10^{-4}$, $mathcal{B}left(chi_{c1}rightarrowLambdabar{Lambda}right)=(1.31pm0.06 pm 0.06 pm0.03)times 10^{-4}$, $mathcal{B}left(chi_{c2}rightarrowLambdabar{Lambda}right)=(1.91pm0.08 pm 0.17 pm0.04)times 10^{-4}$, where the third uncertainties are systematic due to the $psi(3686) rightarrow gamma chi_{c J}$ branching fractions.
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.
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