Studies of Charmonium-like States at BESIII

Abstract

In the quark model, hadrons are dominantly bound states of quark-antiquark pairs (mesons) or three quarks (baryons), but QCD also allows hadronic states to be composed of more quarks bound together. Recently, BESIII, Belle and LHCb have confirmed the existence of four-quark and pentaquark candidates. These new states, along with experimentally observed resonances that do not fit well into the charmonium and bottomonium spectra, present challenges and opportunities for strong interaction theory. In this talk, I will review results on charmonium-like exotic quark states that have been observed by the BESIII experiment at the Beijing Electron Positron Collider II (BEPCII).

Talk presented CIPANP2015. 9 pages, LaTeX, 17 eps figures

References in corpus (9)

• Observation of Two Resonant Structures in e+e- to pi+ pi- psi(2S) via Initial State Radiation at Belle
• Evidence for a Narrow Near-Threshold Structure in the $J/\psi \varphi$ Mass Spectrum in $B^{+}\to J/\psi \varphi K^{+}$ Decays
• Study of $e^{+}{e}^{-}\to \omega {\chi }_{cJ}$ at center-of-mass energies from 4.21 to 4.42 GeV
• Observation of $Z_c(3900{)}^0$ in $e^{+}{e}^{-}\to {\pi }^0{\pi }^{0}J/\psi$
• Observation of a neutral charmoniumlike state $Z_c(4025{)}^0$ in $e^{+}{e}^{-}\to (D^{\ast }{\bar{D}}^{\ast }{)}^0{\pi }^0$
• Observation of a Neutral Structure near the $D{\bar{D}}^{\ast }$ Mass Threshold in $e^{+}{e}^{-}\to (D{\bar{D}}^{\ast }{)}^0{\pi }^0$ at $\sqrt{s}$ = 4.226 and 4.257 GeV
• Measurement of the $e^{+}{e}^{-}\to \eta J/\psi$ cross section and search for $e^{+}{e}^{-}\to {\pi }^{0}J/\psi$ at center-of-mass energies between 3.810 and 4.600~GeV
• Evidence for $e^{+}{e}^{-}\to \gamma {\chi }_{c1,2}$ at center-of-mass energies from 4.009 to 4.360 GeV
• Search for the isospin violating decay $Y(4260)\to J/\psi \eta {\pi }^0$