Observation of $e^{+}{e}^{-}\to {\pi }^0{\pi }^0{h}_c$ and a neutral charmoniumlike structure $Z_c(4020{)}^0$

Abstract

Using data collected with the BESIII detector operating at the Beijing Electron Positron Collider at center-of-mass energies of $\sqrt{s}=4.23$, 4.26, and 4.36~GeV, we observe $\EE\to \pphc$ for the first time. The Born cross sections are measured and found to be about half of those of $\EE\to π^+π^-h_c$ within less than 2$\sigma$. In the ${\pi }^0{h}_c$ mass spectrum, a structure at 4.02~GeV/$c^2$ is found. It is most likely to be the neutral isospin partner of the $\zcp^{\pm}$ observed in the process of $\EE\to π^+π^-h_c$ is found. A fit to the ${\pi }^0{h}_c$ invariant mass spectrum, with the width of the $\zcpn$ fixed to that of its charged isospin partner and possible interferences with non-$\zcpn$ amplitudes neglected, gives a mass of ($4023.9\pm 2.2\pm 3.8$)~MeV/$c^2$ for the $\zcpn$, where the first error is statistical and the second systematic.

7 pages, 2 figures

References in corpus (3)

• Observation of a resonance-like structure in the pi^+- psi' mass distribution in exclusive B-->K pi^+- psi' decays
• Observation of the resonant character of the $Z(4430{)}^{-}$ state
• Prediction of a $Z_c(4000)$ $D^{\ast }{\bar{D}}^{\ast }$ state and relationship to the claimed $Z_c(4025)$

Cited by in corpus (89)

• Hadronic molecules
• The hidden-charm pentaquark and tetraquark states
• The $XYZ$ states: experimental and theoretical status and perspectives
• Multiquark Resonances
• Non-Standard Heavy Mesons and Baryons, an Experimental Review
• Heavy-Quark QCD Exotica
• Exotics: Heavy Pentaquarks and Tetraquarks
• New Exotic Meson and Baryon Resonances from Doubly-Heavy Hadronic Molecules
• Threshold cusps and triangle singularities in hadronic reactions
• Multiquark States
• Emergence of a complete heavy-quark spin symmetry multiplet: seven molecular pentaquarks in light of the latest LHCb analysis
• Four-Quark Hadrons: an Updated Review
• 50 Years of Quantum Chromodynamics
• Observation of a near-threshold structure in the $K^{+}$ recoil-mass spectra in $e^{+}{e}^{-}\to K^{+}(D_s^{-}{D}^{\ast 0}+D_s^{\ast -}{D}^0)$
• Heavy-flavored tetraquark states with the $QQ\bar{Q}\bar{Q}$ configuration
• Heavy-quark spin and flavour symmetry partners of the X(3872) revisited: what can we learn from the one boson exchange model?
• 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 $e^{+}{e}^{-}\to {\pi }^0{\pi }^{0}J/\psi$
• Could the near-threshold $XYZ$ states be simply kinematic effects?
• BB interactions with static bottom quarks from Lattice QCD
• QCD Sum Rules Approach to the $X,Y$ and $Z$ States
• Evidence for the existence of $ud\bar{b}\bar{b}$ and the non-existence of $ss\bar{b}\bar{b}$ and $cc\bar{b}\bar{b}$ tetraquarks from lattice QCD
• The XYZ states revisited
• Confirmation of a charged charmoniumlike state $Z_c(3885{)}^{\mp }$ in $e^{+}{e}^{-}\to {\pi }^{\pm }(D{\bar{D}}^{\ast }{)}^{\mp }$ with double $D$ tag
• Tetraquark state candidates: $Y(4260)$, $Y(4360)$, $Y(4660)$ and $Z_c(4020/4025)$
• Including heavy spin effects in the prediction of a $\bar{b}\bar{b}ud$ tetraquark with lattice QCD potentials
• Employing spin symmetry to disentangle different models for the XYZ states
• Observation of a neutral charmoniumlike state $Z_c(4025{)}^0$ in $e^{+}{e}^{-}\to (D^{\ast }{\bar{D}}^{\ast }{)}^0{\pi }^0$
• Mass spectra of Zc and Zb exotic states as hadron molecules
• 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
• $ud\bar{b}\bar{b}$ tetraquark resonances with lattice QCD potentials and the Born-Oppenheimer approximation
• Hidden-Beauty Charged Tetraquarks and Heavy Quark Spin Conservation
• XYZ-like Spectra from Laplace Sum Rule at N2LO in the Chiral Limit
• Study of charmonium-like and fully-charm tetraquark spectroscopy
• Systematic studies of charmonium-, bottomonium-, and $B_c$-like tetraquark states
• Observation of $e^{+}{e}^{-}\to \omega {\chi }_{c1,2}$ near $\sqrt{s}$ = 4.42 and 4.6 GeV
• Heavy-Quark Symmetry Partners of the Pc(4450) Pentaquark
• The BESIII Physics Programme
• The strange partner of the $Z_c$ structures in a coupled-channels model
• 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
• Zero-energy bound states in the high-temperature superconductors at the two-dimensional limit
• Neutral hidden charm pentaquark states $P_c^0(4380)$ and $P_c^0(4450)$ in ${\pi }^{-}p\to J/\psi n$ reaction
• Triply heavy tetraquark states with the $QQ\bar{Q}\bar{q}$ configuration
• Tuning and validation of hadronic event generator for $R$ value measurements in the tau-charm region
• Charmonium and Charmoniumlike States at the BESIII Experiment
• $D\Xi$ and $D^{\ast }\Xi$ Molecular States from One Boson Exchange
• Search for muoproduction of $X(3872)$ at COMPASS and indication of a new state $\tilde{X}(3872)$
• Importance of meson-meson and of diquark-antidiquark creation operators for a $\bar{b}\bar{b}ud$ tetraquark
• Study on the strong decays of $\varphi (2170)$ and a grand expectation for the future charm-tau factory
• The strong decay patterns of $Z_c$ and $Z_b$ states in the relativized quark model
• Evidence for a neutral near-threshold structure in the $K_{\mathrm{S}}^0$ recoil-mass spectra in $e^{+}{e}^{-}\to K_{\mathrm{S}}^0{D}_s^{+}{D}^{\ast -}$ and $e^{+}{e}^{-}\to K_{\mathrm{S}}^0{D}_s^{\ast +}{D}^{-}$
• Observation of $e^{+}{e}^{-}\to K\bar{K}J/\psi$ at center-of-mass energies from 4.189 to 4.600 GeV
• Photoproduction of the charged charmoniumlike $Z_c^{+}(4200)$
• Measurement of $e^{+}{e}^{-}\to {\pi }^0{\pi }^0\psi (3686)$ at $\sqrt{s}$ from 4.009 to 4.600 GeV and observation of a neutral charmoniumlike structure
• Study of the XYZ states at the BESIII
• Lattice QCD static potentials of the meson-meson and tetraquark systems computed with both quenched and full QCD
• Search for a strangeonium-like structure $Z_s$ decaying into $\varphi \pi$ and a measurement of the cross section $e^{+}{e}^{-}\to \varphi \pi \pi$
• Disentangling the role of the $Y(4260)$ in $e^{+}{e}^{-}\to D^{\ast }{\bar{D}}^{\ast }$ and $D_s^{\ast }{\bar{D}}_s^{\ast }$ via line shape studies
• Observation of $e^{+}{e}^{-}\to \eta h_c$ at center-of-mass energies from 4.085 to 4.600 GeV
• Heavy hadron molecules in effective field theory: the emergence of exotic nuclear landscapes
• Weak Decays of Triply Heavy Tetraquarks $b\bar{c}b\bar{q}$
• Measurements of the branching fractions of ${\eta }_c\to K^{+}{K}^{-}{\pi }^0$, $K_S^0{K}^{\pm }{\pi }^{\mp }$,$2({\pi }^{+}{\pi }^{-}{\pi }^0)$, and $p\bar{p}$
• Measurements of $e^{+}{e}^{-}\to K_S^0{K}^{\pm }{\pi }^{\mp }{\pi }^0$ and $K_S^0{K}^{\pm }{\pi }^{\mp }\eta$ at center-of-mass energies from $3.90$ to $4.60\mathrm{GeV}$
• Physics Accomplishments and Future Prospects of the BES Experiments at the BEPC Collider
• Understanding the ${\eta }_c\rho$ decay mode of $Z_c^{(\prime )}$ via the triangle loop mechanism
• Possible hadronic molecular states composed of $S$-wave heavy-light mesons
• Radiative and pionic transitions $Z_c(4020{)}^0\to X(3872)\gamma$ and $Z_c(4020{)}^{\pm }\to X(3872){\pi }^{\pm }$
• Observation of $e^{+}{e}^{-}\to \varphi {\chi }_{c1}$ and $\varphi {\chi }_{c2}$ at $\sqrt{s}$=4.600 GeV
• Tetraquark states in the bottom sector and the status of the $Y_b$(10890) state
• Estimating decay rate of $X^{\pm }(5568)\to B_s{\pi }^{\pm }$ while assuming them to be molecular states
• The role of charged exotic states in $e^{+}{e}^{-}\to \psi (2S){\pi }^{+}{\pi }^{-}$
• Radially excited axial mesons and the enigmatic $Z_c$ and $Z_b$ in a coupled-channel model
• Measurements of $e^{+}{e}^{-}\to {\eta }_{\mathrm{c}}{\pi }^{+}{\pi }^{-}{\pi }^0$, ${\eta }_{\mathrm{c}}{\pi }^{+}{\pi }^{-}$ and ${\eta }_{\mathrm{c}}{\pi }^0\gamma$ at $\sqrt{s}$ from 4.18 to 4.60\,GeV, and search for a $Z_{\mathrm{c}}$ state close to the $D\bar{D}$ threshold decaying to ${\eta }_{\mathrm{c}}\pi$ at $\sqrt{s}$ = 4.23 GeV
• Discovery potential for the neutral charmoniumlike $Z^0(4200)$ by $\bar{p}p$ annihilation
• How can $X^{\pm }(5568)$ escape detection?
• Role of the short-range dynamics in the formation of $D^{(\ast )}{\bar{D}}^{(\ast )}/B^{(\ast )}{\bar{B}}^{(\ast )}$ hadronic molecules
• Study on decays of $Z_c(4020)$ and $Z_c(3900)$ into $h_c+\pi$
• Radiative decays of the neutral $Z_c(3900)$ and $Z_c(4020)$
• Spin and polarization analysis of $Z_{cs}$ state
• Highlights from the COMPASS experiment at CERN -- Hadron spectroscopy and excitations
• Search for the reaction channel $e^{+}{e}^{-}\to {\eta }_c\eta {\pi }^{+}{\pi }^{-}$ at center-of-mass energies from 4.23 to 4.60 GeV
• Investigation of the $X(4020)$ peak in the $D^{\ast }{\bar{D}}^{\ast }$ and $\pi h_c$ channels
• A Review of Heavy Exotic States
• On the Utility Function of Experiments in Fundamental Science
• Propagators of resonances and rescatterings of the decay products
• Exotic hadrons associated with $b$-quark
• Recent Results on Hadron Spectroscopy from BESIII
• Observation of the first iso-spin Charmonium-like State $Z_c(4020)$ }
• Parametrically narrow tetraquark states containing one heavy quark and one heavy antiquark