Study of the process e(+) e(-) -> pi(0)pi(0)J/psi and neutral charmoniumlike state Z(c)(3900)(0)

Abstract

Cross sections of the process e(+)e(-) -> pi(0)pi(0)J/psi at center-of-mass energies between 3.808 and 4.600 GeV are measured with high precision by using 12.4 fb(-1) of data samples collected with the BESIII detector operating at the BEPCII collider facility. A fit to the measured energy-dependent cross sections confirms the existence of the charmoniumlike state Y(4220). The mass and width of the Y(4220) are determined to be (4220.4 +/- 2.4 +/- 2.3) MeV/c(2) and (46.2 +/- 4.7 +/- 2.1) MeV, respectively, where the first uncertainties are statistical and the second systematic. The mass and width are consistent with those measured in the process e(+)e(-) -> pi(+) pi(-) J/psi. The neutral charmonium-like state Z(c)(3900)(0) is observed prominently in the pi(0)J/psi invariant-mass spectrum, and, for the first time, an amplitude analysis is performed to study its properties. The spin-parity of Z(c) (3900)(0) is determined to be J(P) = 1(+), and the pole position is (3893.1 +/- 2.2 +/- 3.0) - i(22.2 +/- 2.6 +/- 7.0) MeV/c(2), which is consistent with previous studies of electrically charged Z(c) (3900)(+/-). In addition, cross sections of e(+)e(-) -> pi(0)Z(c) (3900)(0) -> pi(0)pi(0)J/psi are extracted, and the corresponding line shape is found to agree with that of the Y(4220).