Experimental Status of Conventional Charmonium Spectroscopy

Abstract

Based on data samples taken by the BESIII, Belle, KEDR and LHCb experiments, many measurements on conventional charmonium spectroscopy were finished in the past years. Some of recent results, such as precise measurements of J/ψ and ψ(2S ) masses, the J/ψ decay width, the J/ψ and ψ(2S ) electronic widths, two-photon width of χc0,2 meson, the χc1,2 resonance parameters with the decays χc0,2 → J/ψµ+µ−, the ηc resonance parameters and observations of X(3823) and X*(3860), were reported.

Study of baryon pair production at BESIII

“…Here the ones (3872), (4260), (4360) (4660), etc., were originally thought to be charmonium states, but some of current evidences and theoretical predictions suggested more exotic explanations, such as a tetraquark state, a molecule or a hybird meson [10,11], which sometimes are so-called charmonium-like states. Beside them, other states (1 ), , / , (2 ), (3773), 2 (3823), 3 (3842), (4040), (4160), (4415), etc., the experimental informations are basically consistent with the predictions from the potential models and lattice QCD [12][13][14][15][16][17], which were thought to be pure charmonium states, it is so-called conventional charmonium states.…”

Electromagnetic Form Factor of Doubly-Strange Hyperon

“…According to potential models, as shown in Figure 9, there are more vector charmonium states between 3.77 and 4.7 GeV [42,44,45]. From experimental studies, beside the four well-established structures, i.e., ψ(3770), ψ(4040) ψ( 4160), and ψ(4415), observed in the inclusive hadronic cross section [16,46], more new states, i.e., Y(4220), Y(4360), Y(4634), and Y(4660), have been reported in initial state radiation processes, i.e., e + e − → γ ISR π + π − J/ψ or e + e − → γ ISR π + π − ψ(3686) in the BABAR experiment [47][48][49][50] and Belle experiment [51][52][53][54][55], or in direct production processes in the CLEO [56] and BESIII experiments [57][58][59][60][61][62]. However, till now, no more experimental information for hyperon production above the open charm threshold associated with these states was found, with the exception of the ψ(4634) resonance observed in Λ + c Λ− c by the Belle experiment [54].…”