25-29 September 2017
Salamanca, Spain
Europe/Zurich timezone

Charmonium decays at BESIII

29 Sep 2017, 09:00
Aula 2.3

Aula 2.3

Talk Hadron decays Hadron decays


Dr Bo Zheng (University of South China)


The BESIII Experiment at the Beijing Electron Positron Collider (BEPC2) has accumulated the world's largest samples of e+e- collisions in the tau-charm region. Using a sample of 106 million psi(3686) decays, the branch fractions of psi(3686) -> gamma chi_c0, gamma chi_c1, gamma chi_c2 are determined to be (9.389 +- 0.014 +- 0.332)%, (9.905 +- 0.011 +- 0.353)%, and (9.621 +- 0.013 +- 0.272)%, respectively. The branching fraction and the angular distributions of J/psi and psi(3686) decays to Lambda anti-Lambda and Sigma^0 anti-Sigma^0 final states are measured. J/psi and psi(3686) decays to Sigma(1385)^0 anti-Sigma(1385)^0 and Xi^0 anti-Xi^0 are measured. The decays to Sigma(1385)^0 anti-Sigma(1385)^0 are observed for the first time, and the angular parameters of these decays are also measured first time. Observation of hc radiative decay hc -> gamma eta' and evidence for hc -> gamma eta. The branching fractions are measured to be (1.52 +- 0.27 +- 0.29)/10^3 and (4.7 +- 1.5 +- 1.4)/10^4, respectively. Both of them are the first observations. Measurement of higher-order multipile amplitudes in psi(3686) -> gamma chi_c1,2 with chi_c1,2 -> gamma J/psi and search for the eta_c(2S) -> gamma J/psi transition. The normalized magnetic-quadrupole (M2) amplitude for psi(3686) -> gamma chi_c1,2 -> gamma gamma J/psi and the normalized electricoctupole (E3) amplitudes for psi(3686) -> gamma chi_c2, chi_c2-> gamma J/psi are determined. The decays psi(3686) -> e+ e- chi_c0,1,2 and chi_c0,1,2 -> e+ e-J/psi are searched, and they are observed for the first time. Improved measurements of branching fractions for eta_c -> phi phi and omega phi. The branching fraction of eta_c -> phi phi is measured with improved precision. No significant signal for the double OZI-suppressed decay of eta_c -> omega phi is observed, and the upper limit on the branching fraction is determined.

Primary author

Dr Bo Zheng (University of South China)

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