Narrow Results

The process $e^{+}{e}^{-}\to K_S^0{K}^{\pm }{\pi }^{\mp }{\pi }^0/\eta$ has been studied at center-of-energies between 3.90 to 4.60 GeV using 5.2 fb⁻¹ luminosity data samples collected with the BESIII detector. In this proceeding, we present the results about the cross sections and the upper limits of charmonium resonance Y (4260) and $Z_c^{0,\pm }$, that are searched through decay modes $K_S^0{K}^{\pm }{\pi }^{\mp }{\pi }^0/\eta$.

This report reviewed the recently discovered Z_c(3900) at around 3.9 GeV/c² in the π±J/ψ mass spectrum by the Belle and BESIII collaborations simultaneously. Belle collaboration observed it in the process e⁺e⁻ → π⁺π⁻ J/ψ within the Y (4260) signal region with a 967 fb⁻¹ data sample using initial-stateradiation technology. BESIII collaboration discovered it in the same process at a fixed center-of-mass energy of 4.260 GeV using a 525 pb⁻¹ data sample. The measured resonance masses and widths from Belle and BESIII measurements are consistent with each other within the errors. The Z_c(3900) can be interpreted as a new charged charmonium-like state.