Hadronic Transition chi(c1)(1P) to eta(c) plus two pions at the Beijing   Spectrometer BES and the Cornell CLEO-c
  Hadronic transitions of the chi(cj)(1P) states have not been studied yet. We calculate the rate of the hadronic transition chi(c1)(1P) to eta(c) plus two pions in the framework of QCD multipole expansion. We show that this process can be studied experimentally at the upgraded Beijing Spectrometer BES III and the Cornell CLEO-c. 
Qin Lu and Yu-Ping Kuang