Using a sample of 2.25 × 108 J/? events collected with the BESIII detector at the BEPCII collider, we search for the J/? semileptonic weak decay J/? ? D-s e+?e+ c.c. with a much higher sensitivity than previous searches. ...

Using data collected with the BESIII detector operating at the Beijing Electron Positron Collider at center-of-mass energies of ?s = 4.23, 4.26, and 4.36 GeV, we observe e+e- ? ?+?-hc for the first time. The Born cross ...