LIGHT UNFLAVORED MESONS
($\mathit S$ = $\mathit C$ = $\mathit B$ = 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   JSON PDGID:
M267

${{\mathit \eta}_{{{1}}}{(1855)}}$

$I^G(J^{PC})$ = $0^+(1^{- +})$ 
Meson with exotic (non-${{\mathit q}}{{\overline{\mathit q}}}$) quantum numbers. A state decaying into ${{\mathit \eta}}{{\mathit \eta}^{\,'}}$ with possible quantum numbers ${}^{}1{}^{-+}$ was reported earlier in this mass region BARBERIS 2000A in high energy central ${{\mathit p}}{{\mathit p}}$ production and by ALDE 1991B in ${{\mathit \pi}^{-}}{{\mathit p}}$ interactions, see the ${{\mathit f}_{{{2}}}{(1910)}}$, and the review on "Spectroscopy of Light Meson Resonances."
${{\mathit \eta}_{{{1}}}{(1855)}}$ MASS $1855^{+11}_{-9}$ MeV 
 
${{\mathit \eta}_{{{1}}}{(1855)}}$ WIDTH $188$ $\pm19$ MeV 
 
Mode  
Fraction ($\Gamma_i$ / $\Gamma$) Scale Factor/
Conf. Level		 P(MeV/c)  
$\Gamma_{1}$ ${{\mathit \eta}}{{\mathit \eta}^{\,'}}$ seen 528