LIGHT UNFLAVORED MESONS
($\mathit S$ = $\mathit C$ = $\mathit B$ = $\mathit{0}$)
For $\mathit I = 1$ (${{\mathit \pi}}$, ${{\mathit b}}$, ${{\mathit \rho}}$, ${{\mathit a}}$): ${\mathit {\mathit u}}$ ${\mathit {\overline{\mathit d}}}$, (${\mathit {\mathit u}}$ ${\mathit {\overline{\mathit u}}}−{\mathit {\mathit d}}$ ${\mathit {\overline{\mathit d}}})/\sqrt {2 }$, ${\mathit {\mathit d}}$ ${\mathit {\overline{\mathit u}}}$;
for $\mathit I = 0$ (${{\mathit \eta}}$, ${{\mathit \eta}^{\,'}}$, ${{\mathit h}}$, ${{\mathit h}^{\,'}}$, ${{\mathit \omega}}$, ${{\mathit \phi}}$, ${{\mathit f}}$, ${{\mathit f}^{\,'}}$): ${\mathit {\mathit c}}_{{\mathrm {1}}}({{\mathit u}}{{\overline{\mathit u}}}$ $+$ ${{\mathit d}}{{\overline{\mathit d}}}$) $+$ ${\mathit {\mathit c}}_{{\mathrm {2}}}({{\mathit s}}{{\overline{\mathit s}}}$)
INSPIRE search

${{\mathit \eta}{(2370)}}$ $I^G(J^{PC})$ = $0^+(0^{- +})$ 


was ${{\mathit X}{(2370)}}$
$\mathit J{}^{PC} = 0{}^{-+}$ determined by ABLIKIM 2024.
${{\mathit \eta}{(2370)}}$ MASS   $2377 \pm9$ MeV 
${{\mathit \eta}{(2370)}}$ WIDTH   $148 {}^{+80}_{-28}$ MeV (S = 1.7)
$\Gamma_{1}$ ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \eta}^{\,'}}$  seen 683
$\Gamma_{2}$ ${{\mathit K}_S^0}$ ${{\mathit K}_S^0}$ ${{\mathit \eta}^{\,'}}$  seen 677
$\Gamma_{3}$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \eta}^{\,'}}$  seen 973
$\Gamma_{4}$ ${{\mathit f}_{{{0}}}{(980)}}{{\mathit \eta}^{\,'}}$  seen 681
$\Gamma_{5}$ ${{\mathit \eta}}{{\mathit \eta}}{{\mathit \eta}^{\,'}}$  not seen 597