Study of the resonance structures in the process e+e- →π+π-J/ψ

Abstract

Using about 23 fb-1 of data collected with the BESIII detector operating at the BEPCII storage ring, a precise measurement of the e+e-→π+π-J/ψ Born cross section is performed at center-of-mass energies from 3.7730 to 4.7008 GeV. Two structures, identified as the Y(4220) and the Y(4320) states, are observed in the energy-dependent cross section with a significance larger than 10σ. The masses and widths of the two structures are determined to be (M,Γ)=(4221.4±1.5±2.0 MeV/c2,41.8±2.9±2.7 MeV) and (M,Γ)=(4298±12±26 MeV/c2,127±17±10 MeV), respectively. A small enhancement around 4.5 GeV with a significance about 3σ, compatible with the ψ(4415), might also indicate the presence of an additional resonance in the spectrum. The inclusion of this additional contribution in the fit to the cross section affects the resonance parameters of the Y(4320) state. © 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.