No Arabic abstract
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.
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 a sample of $1.06times10^8 psip$ events produced in $e^+e^-$ collisions at $sqrt{s}$ = 3.686 GeV and collected with the BESIII detector at the BEPCII collider, we present studies of the decays $klx+c.c.$ and $gklx+c.c.$. We observe two hyperons, $Xi(1690)^-$ and $Xi(1820)^-$, in the $K^-Lambda$ invariant mass distribution in the decay $klx+c.c.$ with significances of $4.9 sigma$ and $6.2 sigma$, respectively. The branching fractions of $klx+c.c.$, $ksx+c.c.$, $psiptogamma chi_{cJ}to gamma K^- Lambda bar{Xi}^+ +c.c.$ $(J=0, 1, 2)$, and $psipto Xi(1690/1820)^{-} bar{Xi}^++c.c$ with subsequent decay $Xi(1690/1820)^-to K^-Lambda$ are measured for the first time.
We measured the branching fractions of the decays $chi_{cJ}toSigma^{-}bar{Sigma}^{+}$ for the first time using the final states $nbar{n}pi^{+}pi^{-}$. The data sample exploited here is $448.1times10^{6}$ $psi(3686)$ events collected with BESIII. We find $mathcal{B}(chi_{cJ}rightarrowSigma^{-}bar{Sigma}^{+}) = (51.3pm2.4pm4.1)times10^{-5},, (5.7pm1.4pm0.6)times10^{-5},, rm{and}~ (4.4pm1.7pm0.5)times10^{-5}$, for $J=0,1,2$, respectively, where the first uncertainties are statistical and the second systematic.
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.
Using $pp$ collisions corresponding to 3$,text{fb}^{-1}$ integrated luminosity, recorded by the LHCb experiment at centre-of-mass energies of 7 and 8$,text{TeV}$, the ratio of branching fractions begin{align*} mathcal{B}(Lambda^0_b!topsi(2S) Lambda )/mathcal{B}(Lambda^0_b!to J/psi Lambda)= 0.513 pm 0.023, (text{stat}) pm 0.016 , (text{syst}) pm 0.011, (mathcal{B}) end{align*} is determined. The first uncertainty is statistical, the second is systematic and the third is due to the external branching fractions used.