We perform a helicity amplitude analysis for the processes of $e^+e^-$$rightarrow$$J/psi,psi(2S)rightarrowXi(1530)barXi(1530)rightarrowpipiXibarXirightarrowLambdabarLambda4pirightarrow pbar{p}6pi$. The joint angular distribution for these processes are obtained, which allows a proper estimation of the detection efficiency using helicity amplitude information. In addition, the sensitivities of measurement of hyperon asymmetry decay parameters for these processes are discussed.
Using 448.1 $times$ $10^{6}$ $psi(3686)$ events collected with the BESIII detector at BEPCII, we employ a single-baryon tagging technique to make the first observation of $psi(3686)rightarrowXi(1530)^{-}barXi(1530)^{+}$ and $Xi(1530)^{-}barXi^{+}$ decays with a statistical significance of more than 10$sigma$ and 5.0$sigma$, respectively. The branching fractions are measured to be $cal{B}$$[psi(3686)rightarrowXi(1530)^{-}barXi(1530)^{+}] $ = (11.45 $pm$ 0.40 $pm$ 0.59) $times$ $10^{-5}$ and $cal{B}$$[psi(3686)rightarrowXi(1530)^{-}barXi^{+}]$ = (0.70 $pm$ 0.11 $pm$ 0.04) $times$ $10^{-5}$. The angular distribution parameter for $psi(3686)rightarrowXi(1530)^{-}barXi(1530)^{+}$ is determined to be $alpha$ = 0.40 $pm$ 0.24 $pm$ 0.06, which agrees with the theoretical predictions within 1$sigma$. The first uncertainties are statistical, and the second systematic.
Using $(448.1pm2.9)times 10^{6}$ $psi(3686)$ events collected with the BESIII detector and a single-baryon tagging technique, we present the first observation of the decays $psi(3686)toXi(1530)^{0}bar{Xi}(1530)^{0}$ and $Xi(1530)^{0}bar{Xi}^0$. The branching fractions are measured to be ${cal{B}}(psi(3686)toXi(1530)^{0}bar{Xi}(1530)^{0}) = (6.77pm0.14pm0.39)times10^{-5}$ and ${cal{B}}(psi(3686)toXi(1530)^{0}bar{Xi}^{0}) = (0.53pm0.04pm0.03)times10^{-5}$. Here, the first and second uncertainties are statistical and systematic, respectively. In addition, the parameter associated with the angular distribution for the decay $psi(3686)toXi(1530)^{0}bar{Xi}(1530)^0$ is determined to be $alpha = 0.32pm0.19pm0.07$, in agreement with theoretical predictions within one standard deviation.
The SU(3)-flavor violating decay $J/psitoXi(1530)^{-}barXi^{+}+c.c.$ is studied using $(1310.6pm7.0)times 10^{6} ~J/psi$ events collected with the BESIII detector at BEPCII and the branching fraction is measured to be ${cal{B}}(J/psitoXi(1530)^{-}barXi^{+}+c.c.)=(3.17pm0.02_{rm stat.}pm0.08_{rm syst.})times10^{-4}$. This is consistent with previous measurements with an improved precision. The angular parameter for this decay is measured for the first time and is found to be $alpha=-0.21pm0.04_{rm stat.}pm0.06_{rm syst.}$. In addition, we report evidence for the radiative decay $Xi(1530)^{-}togammaXi^- $ with a significance of 3.9$sigma$, including the systematic uncertainties. The 90% confidence level upper limit on the branching fraction is determined to be $mathcal{B}(Xi(1530)^{-}togammaXi^- )leq3.7$%.
Using a sample of $1.06 times 10^{8}$ $psi(2S)$ events collected with the BESIII detector at BEPCII, the decay $psi(2S) to p bar{p}eta$ is studied. A partial wave analysis determines that the intermediate state N(1535) with a mass of $1524pm5^{+10}_{-4}$ MeV/$c^2$ and a width of $130^{+27+57}_{-24-10}$ MeV/$c^2$ is dominant in the decay; the product branching fraction is determined to be $B(psi(2S) to N(1535)bar{p})times B(N(1535)to peta)+c.c. = (5.2pm0.3^{+3.2}_{-1.2})times 10^{-5}$. Furthermore, the branching fraction of $psi(2S) to eta p bar{p}$ is measured to be $(6.4pm0.2pm0.6)times 10^{-5}$.