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