Measurement of $e^+e^- \to \gamma\chi_cJ$ via initial state radiation at Belle

摘要: The process e+e−→γχcJ (J=1, 2) is studied via initial state radiation using 980 fb−1 of data at and around the Υ(nS) (n=1, 2, 3, 4, 5) resonances collected with the Belle detector at the KEKB asymmetric-energy e+e−collider. No significant signal is observed except from ψ(2S) decays. Upper limits on the cross sections between s√=3.80 and 5.56 GeV are determined at the 90% credibility level, which range from few pb to a few tens of pb. We also set upper limits on the decay rate of the vector charmonium [ψ(4040), ψ(4160), and ψ(4415)] and charmoniumlike [Y(4260), Y(4360), and Y(4660)] states to γχcJ.