Discussion on Cross Section Measurement for D^-D Production around ψ（3770）

We give a brief discussion on the measurement of the cross section for D^-D production around the ψ（3770） resonance, and point out a new calculation of the cross sections based on the absolute measurements. Compared with single tag and double tag analyses, the new calculation provides us with many more opportunities to perform the cross section measurement.     

Experimental review of e~+e~-→ππh_c

We review the recent BESIII measurement of e~+e~-→ππh_c in which its line shape is studied between the center-of-mass energies of 3.9 to 4.42 Ge V and an iso-vector charmonium-like state Z_c(4020) is observed in the invariant mass of πhc at the BESIII experiment. The charged Z_c(4020)~± is the second observed Z_c state following Z_c(3900), while the Z_c(4020)~0 is the first observed neutral Z_c state. The line shape of σ(e~+e~-→ππh_c) is also reanalyzed in view of searching for the Y state and the existence of the Y(4220) state is confirmed and compared with the previous work of the BESIII experiment.