LIGHT UNFLAVORED MESONS
($\boldsymbol S$ = $\boldsymbol C$ = $\boldsymbol B$ = 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 search

${{\boldsymbol \eta}{(1405)}}$ $I^G(J^{PC})$ = $0^+(0^{- +})$ 

See also the ${{\mathit \eta}{(1475)}}$.
See related review:
Pseudoscalar and Pseudovector Mesons in the 1400 MeV Region
${{\boldsymbol \eta}{(1405)}}$ MASS
Mass $\mathit m$   $1408.8 \pm2.0$ MeV (S = 2.2)
${{\mathit \eta}}{{\mathit \pi}}{{\mathit \pi}}$ MODE   $1405.8 \pm2.6$ MeV (S = 2.3)
${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}$ MODE ( ${{\mathit a}_{{0}}{(980)}}{{\mathit \pi}}$ or direct ${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}$ )   $1413.9 \pm1.7$ MeV (S = 1.1)
${{\mathit \pi}}{{\mathit \pi}}{{\mathit \gamma}}$ MODE   $1403 \pm17$ MeV (S = 1.8)
4 ${{\mathit \pi}}$ MODE
${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}$ MODE (unresolved)
${{\boldsymbol \eta}{(1405)}}$ WIDTH
Full width $\Gamma $   $50.1 \pm2.6$ MeV (S = 1.7)
${{\mathit \eta}}{{\mathit \pi}}{{\mathit \pi}}$ MODE   $52.6 \pm3.2$ MeV (S = 1.3)
${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}$ MODE ( ${{\mathit a}_{{0}}{(980)}}{{\mathit \pi}}$ or direct ${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}$ )   $48 \pm4$ MeV (S = 2.1)
${{\mathit \pi}}{{\mathit \pi}}{{\mathit \gamma}}$ MODE   $89 \pm17$ MeV (S = 1.7)
4 ${{\mathit \pi}}$ MODE
${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}$ MODE (unresolved)
$\Gamma_{1}$ ${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}$ seen424
$\Gamma_{2}$ ${{\mathit \eta}}{{\mathit \pi}}{{\mathit \pi}}$ seen562
$\Gamma_{3}$ ${{\mathit a}_{{0}}{(980)}}{{\mathit \pi}}$ seen345
$\Gamma_{4}$ ${{\mathit \eta}}{({\mathit \pi}{\mathit \pi})_{{\mathit S}-{\text{wave}}}}$ seen
$\Gamma_{5}$ ${{\mathit f}_{{0}}{(980)}}{{\mathit \pi}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ not seen
$\Gamma_{6}$ ${{\mathit f}_{{0}}{(980)}}{{\mathit \eta}}$ seen-1
$\Gamma_{7}$ 4 ${{\mathit \pi}}$ seen639
$\Gamma_{8}$ ${{\mathit \rho}}{{\mathit \rho}}$ $<58\%$CL=100%-1
$\Gamma_{9}$ ${{\mathit \gamma}}{{\mathit \gamma}}$ 704
$\Gamma_{10}$ ${{\mathit \rho}^{0}}{{\mathit \gamma}}$ seen491
$\Gamma_{11}$ ${{\mathit \phi}}{{\mathit \gamma}}$ 336
$\Gamma_{12}$ ${{\mathit K}^{*}{(892)}}{{\mathit K}}$ seen123