New Observations on Light Hadron Spectroscopy at BESIII

Abstract

With samples of 220 million J/ψ events and 110 million ψ events collected in the BESIII detector, pp mass threshold enhancement is studied. The enhancement is evident in J/ψ radiative decay, which is consistent with BESII result. No significant narrow enhancement is observed in ψ radiative decay. For J/ψ → γπ + π − η decay, the X(1835), which was previously observed by BESII, is confirmed with a statistical significance that is larger than 20σ . In addition, in the π + π − η invariant mass spectrum, the X(2120) and the X(2370), are observed with statistical significances larger than 7.2σ and 6.7σ , respectively. A new process J/ψ → ωX(1870) → ωa 0 π is also observed in J/ψ → ωπ + π − η decay.