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

${{\boldsymbol X}{(4100)}^{\pm}}$ $I^G(J^{PC})$ = $1^-(?^{? ?})$ 

Properties incompatible with a ${{\mathit q}}{{\overline{\mathit q}}}$ structure (exotic state). See the review on non- ${{\mathit q}}{{\overline{\mathit q}}}$ states. Reported by AAIJ 2018AN in the ${{\mathit \eta}_{{c}}{(1S)}}{{\mathit \pi}^{-}}$ invariant mass distribution in ${{\mathit B}^{0}}$ $\rightarrow$ ${{\mathit \eta}_{{c}}{(1S)}}{{\mathit K}^{+}}{{\mathit \pi}^{-}}$ decays with a significance of 3.4$\sigma $. $\mathit J{}^{P} = 0{}^{+}$ or ${}^{}1{}^{-}$ assignment consistent with data.
${{\mathit X}{(4100)}^{\pm}}$ MASS   $4096 \pm28$ MeV 
${{\mathit X}{(4100)}^{\pm}}$ WIDTH   $152 {}^{+80}_{-70}$ MeV 
$\Gamma_{1}$ ${{\mathit \eta}_{{c}}{(1S)}}{{\mathit \pi}^{-}}$ seen