Vector states above open charm threshold at BESIII

Zhi-Yong Wang,Y Aharonov,S Kabana,L Bravina

doi:10.1051/epjconf/201818202128

Abstract

Based on the the large XYZ data sample collected at BESIII detector, we study the vector states above charm threshold, including the traditional charmonium and charmonium-like states, Y in many decay modes. For example, e+e- → hc, π+π-J/Ψ,Ψ(3686); e+e- → η(ή)J/Ψ. Many charmonium and charmonium-like candidates are found, but some of them need to be confirmed further with much larger data.

Highlights

The process π+π− J/ψ at center-of-mass (c.m.) energies between 3.8 and 5.0 GeV was first studied by the BABAR experiment using an initial-state-radiation (ISR) technique, and a new structure, the Y(4260),was reported with a mass around 4.26 GeV/c2
The observation of the states Y(4360) and Y(4660) in e+e− → π+π−ψ(3686) [7], together with the newly observed resonant structures in e+e− → ωχcJ (J=0,1,2) and e+e− → π+π−hc, overpopulates the vector charmonium spectrum predicted by potential models [8]. All of this indicates that the Y states may not be conventional charmonium states, and they are good candidates for new types of exotic particles, such as hybrids, tetraquarks, or meson molecules
√ With the data samples collected at four energy points ranging from s = 4.009 to 4.420 GeV, we present a first observation of e+e− → γX(3872) → γπ+π− J/ψ, J/ψ → + −)

Summary

Introduction

The process π+π− J/ψ at center-of-mass (c.m.) energies between 3.8 and 5.0 GeV was first studied by the BABAR experiment using an initial-state-radiation (ISR) technique, and a new structure, the Y(4260),was reported with a mass around 4.26 GeV/c2 This observation was immediately confirmed by the CLEO [1] and Belle experiments [2] in the same process. The observation of the states Y(4360) and Y(4660) in e+e− → π+π−ψ(3686) [7], together with the newly observed resonant structures in e+e− → ωχcJ (J=0,1,2) and e+e− → π+π−hc, overpopulates the vector charmonium spectrum predicted by potential models [8].

EPJ Web of Conferences

Summary