No Arabic abstract
Using a sample of 106 million $psi(3686)$ decays, the branching fractions of $psi(3686) to gamma chi_{c0}, psi(3686) to gamma chi_{c1}$, and $psi(3686) to gamma chi_{c2}$ are measured with improved precision to be $(9.389 pm 0.014 pm 0.332),%$, $(9.905 pm 0.011 pm 0.353),% $, and $(9.621 pm 0.013 pm 0.272),% $, respectively, where the first uncertainties are statistical and the second ones are systematic. The product branching fractions of $psi(3686) to gamma chi_{c1}, chi_{c1} to gamma J/psi$ and $psi(3686) to gamma chi_{c2}, chi_{c2} to gamma J/psi$ and the branching fractions of $chi_{c1} to gamma J/psi$ and $chi_{c2} to gamma J/psi$ are also presented.
Using $4.479 times 10^{8}$ $psi(3686)$ events collected with the BESIII detector, we search for the decays $psi(3686) rightarrow e^{+}e^{-}chi_{c0,1,2}$ and $chi_{c0,1,2} rightarrow e^{+}e^{-}J/psi$. The decays $psi(3686) rightarrow e^{+}e^{-}chi_{c0,1,2}$ and $chi_{c0,1,2} rightarrow e^{+}e^{-}J/psi$ are observed for the first time. The measured branching fractions are $mathcal{B}(psi(3686) rightarrow e^{+}e^{-}chi_{c0,1,2}) = (11.7 pm 2.5 pm 1.0)times10^{-4}$, $(8.6 pm 0.3 pm 0.6)times10^{-4}$, $(6.9 pm 0.5 pm 0.6)times10^{-4}$, and $mathcal{B}(chi_{c0,1,2} rightarrow e^{+}e^{-}J/psi) = (1.51 pm 0.30 pm 0.13)times10^{-4}$, $(3.73 pm 0.09 pm 0.25)times10^{-3}$, $(2.48 pm 0.08 pm 0.16)times10^{-3}$. The ratios of the branching fractions $frac{mathcal{B}(psi(3686) rightarrow e^{+}e^{-}chi_{c0,1,2})}{mathcal{B}(psi(3686) rightarrow gammachi_{c0,1,2})}$ and $frac{mathcal{B}(chi_{c0,1,2} rightarrow e^{+}e^{-}J/psi)}{mathcal{B}(chi_{c0,1,2} rightarrow gamma J/psi)}$ are also reported.
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.
Analyzing $(448.1pm2.9)times10^6$ $psi(3686)$ events collected with the BESIII detector at the BEPCII collider, the $psi(3686)to omega K_{S}^{0}K_{S}^{0}$ decay is observed for the first time. The branching fraction for this decay is determined to be $mathcal{B}_{psi(3686)to omega K_{S}^{0}K^{0}_{S}}$=$(7.04pm0.39pm0.36)$$times10^{-5}$, where the first uncertainty is statistical and the second is systematic.
With $1.06times 10^8$ $psi(3686)$ events collected with the BESIII detector, the branching fraction of $psi(3686) to omega K^+ K^-$ is measured to be $(1.54 pm 0.04 pm 0.11) times 10^{-4}$. This is the most precise result to date, due to the largest $psi(3686)$ sample, improved signal reconstruction efficiency, good simulation of the detector performance, and a more accurate knowledge of the continuum contribution. Using the branching fraction of $J/psi to omega K^+ K^-$, the ratio $mathcal{B}(psi(3868) to K^+K^-) / mathcal{B}(J/psi to K^+K^-)$ is determined to be $(18.4 pm 3.7),%$. This constitutes a significantly improved test of the $12,%$ rule, with the uncertainty now dominated by the $J/psi$ branching fraction.
Using a sample of 1.06 times 10^8 psi^{prime} decays collected by the BESIII detector, chi_{c0} and chi_{c2} decays into pi^0pi^0 and etaeta are studied. The branching fraction results are Br(chi_{c0}topi^0pi^0)=(3.23pm 0.03pm0.23 pm 0.14)times 10^{-3}, Br(chi_{c2}topi^0pi^0)=(8.8pm 0.2pm 0.6pm0.4)times 10^{-4}, Br(chi_{c0}toetaeta)=(3.44pm 0.10pm0.24 pm0.2)times 10^{-3}, and Br(chi_{c2}toetaeta)=(6.5pm 0.4pm 0.5pm 0.3)times 10^{-4}, where the uncertainties are statistical, systematic due to this measurement, and systematic due to the branching fractions of psi^{prime}togammachi_{cJ}, respectively. The results provide information on the decay mechanism of chi_c states into pseudoscalars.