https://indico.ihep.ac.cn//event/8183/

Kai gave an introduction to Search for Invisible Decays of a Dark Photon Produced in e+e- Collisions at BABAR. This search used BDT(boosted decision tree) techniques to further reduce background. Decision trees are powerful, but not stable. Any small change in training data could produce large change in tree.

Then Maoqiang gave a special topic on Discovery of a Narrow Resonance in e+e- Annihilation(particle psi). Together with his JC last week Experimental Observation of a Heavy Particle J, the discovery of J/psi was described.