${\boldsymbol {\boldsymbol c}}$ ${\boldsymbol {\overline{\boldsymbol c}}}$ MESONS(including possibly non- ${\boldsymbol {\boldsymbol q}}$ ${\boldsymbol {\overline{\boldsymbol q}}}$ states) INSPIRE search

# ${{\boldsymbol Z}_{{c}}{(3900)}}$ $I^G(J^{PC})$ = $1^+(1^{+ -})$

was ${{\mathit X}{(3900)}}$
Properties incompatible with a ${{\mathit q}}{{\overline{\mathit q}}}$ structure (exotic state). See the review on non- ${{\mathit q}}{{\overline{\mathit q}}}$ states. Charged ${{\mathit Z}_{{c}}{(3900)}}$ seen as a peak in the invariant mass distribution of the ${{\mathit J / \psi}}{{\mathit \pi}^{\pm}}$ system by BES III (ABLIKIM 2013T) in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit J / \psi}}$ at c.m. energy of 4.26 GeV and by radiative return from ${{\mathit e}^{+}}{{\mathit e}^{-}}$ collisions at $\sqrt {s }$ from 9.46 to 10.86 GeV at Belle (LIU 2013B). Partial wave analysis of ABLIKIM 2017J determines $\mathit J{}^{P} = 1{}^{+}$ with more than 7$~\sigma$ significance. Neutral ${{\mathit Z}_{{c}}{(3900)}}$ seen in the ${{\mathit J / \psi}}{{\mathit \pi}^{0}}$ invariant mass distribution in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{0}}{{\mathit \pi}^{0}}{{\mathit J / \psi}}$ at c.m. energies of 4.23, 4.26, and 4.36 GeV by BES III (ABLIKIM 2015U) and at 4.17 GeV by XIAO 2013A. Peaks in ( ${{\mathit D}}{{\overline{\mathit D}}^{*}}$ )${}^{0,\pm{}}$ reported by BES III (ABLIKIM 2014A, ABLIKIM 2015AB) are assumed to be related.
 ${{\mathit Z}_{{c}}{(3900)}}$ MASS $3888.4 \pm2.5$ MeV (S = 1.7)
 ${{\mathit Z}_{{c}}{(3900)}}$ WIDTH $28.3 \pm2.5$ MeV