Measurement of e+e- →π0π0ψ (3686) at s from 4.009 to 4.600 GeV and observation of a neutral charmoniumlike structure MEASUREMENT of ... M. ABLIKIM et al.

Using e+e- collision data collected with the BESIII detector at the BEPCII collider corresponding to an integrated luminosity of 5.2 fb-1 at center-of-mass energies (s) from 4.009 to 4.600 GeV, the process e+e-→π0π0ψ(3686) is studied for the first time. The corresponding Born cross sections are measured and found to be half of those of the reaction e+e-→π+π-ψ(3686). This is consistent with the expectation from isospin symmetry. Furthermore, the Dalitz plots for π0π0ψ(3686) are accordant with those of π+π-ψ(3686) at all energy points, and a neutral analog to the structure in π±ψ(3686) around 4040 MeV/c2 first observed at s=4.416 GeV is observed in the isospin neutral mode at the same energy.