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

${{\boldsymbol \eta}^{\,'}{(958)}}$ $I^G(J^{PC})$ = $0^+(0^{- +})$ 

${{\mathit \eta}^{\,'}{(958)}}$ MASS   $957.78 \pm0.06$ MeV 
${{\mathit \eta}^{\,'}{(958)}}$ WIDTH   $0.188 \pm0.006$ MeV 
${{\boldsymbol \eta}^{\,'}{(958)}}$ $\rightarrow$ ${{\boldsymbol \eta}}{{\boldsymbol \pi}}{{\boldsymbol \pi}}$ DECAY PARAMETERS $\vert $MATRIX ELEMENT$\vert ^2$ = $\vert $1 + $\alpha {}\boldsymbol Y\vert ^2$ + $\boldsymbol C{}\boldsymbol X$ + $\boldsymbol D{}\boldsymbol X{}^{2}$
$\mathit Re(\alpha $) decay parameter
$\mathit Im(\alpha $) decay parameter
$\mathit C$ decay parameter
$\mathit D$ decay parameter
${{\boldsymbol \eta}^{\,'}{(958)}}$ $\rightarrow$ ${{\boldsymbol \eta}}{{\boldsymbol \pi}}{{\boldsymbol \pi}}$ DECAY PARAMETERS $\vert $MATRIX ELEMENT$\vert ^2$ ${}\propto$ 1 + $\boldsymbol a~Y$ + $\boldsymbol b~Y{}^{2}$ + $\boldsymbol c~X$ + $\boldsymbol d~X{}^{2}$
$\mathit a$ decay parameter
$\mathit b$ decay parameter
$\mathit c$ decay parameter
$\mathit d$ decay parameter
${{\boldsymbol \eta}^{\,'}{(958)}}$ $\beta $ PARAMETER $\vert $MATRIX ELEMENT$\vert ^2$ = (1 + 2$\beta {{\boldsymbol Z}}$)
$\beta $ decay parameter   $-0.61 \pm0.08$  (S = 1.2)
${{\boldsymbol \eta}^{\,'}{(958)}}{}^{C}$-NONCONSERVING DECAY PARAMETER
DECAY ASYMMETRY PARAMETER FOR ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \gamma}}$   $-0.03 \pm0.04$  
${{\mathit \eta}^{\,'}{(958)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ TRANSITION FORM FACTOR SLOPE   $1.62 \pm0.17$ GeV${}^{-2}$ 
$\Gamma_{1}$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \eta}}$  $(42.5\pm{0.5})\%$ 232
$\Gamma_{2}$ ${{\mathit \rho}^{0}}{{\mathit \gamma}}$ (including non-resonant ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \gamma}}$)  $(29.5\pm{0.4})\%$ 165
$\Gamma_{3}$ ${{\mathit \rho}^{0}}{{\mathit \gamma}}$  165
$\Gamma_{4}$ ${{\mathit \pi}^{0}}{{\mathit \pi}^{0}}{{\mathit \eta}}$  $(22.4\pm{0.5})\%$ 239
$\Gamma_{5}$ ${{\mathit \omega}}{{\mathit \gamma}}$  $(2.52\pm{0.07})\%$ 159
$\Gamma_{6}$ ${{\mathit \omega}}{{\mathit e}^{+}}{{\mathit e}^{-}}$  $(2.0\pm{0.4})\times 10^{-4}$ 159
$\Gamma_{7}$ ${{\mathit \gamma}}{{\mathit \gamma}}$  $(2.307\pm{0.033})\%$ 479
$\Gamma_{8}$ 3 ${{\mathit \pi}^{0}}$  $(2.50\pm{0.17})\times 10^{-3}$ 430
$\Gamma_{9}$ ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}{{\mathit \gamma}}$  $(1.13\pm{0.28})\times 10^{-4}$ 467
$\Gamma_{10}$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$  $<2.9\times 10^{-5}$ CL=90%401
$\Gamma_{11}$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$  $(3.61\pm{0.17})\times 10^{-3}$ 428
$\Gamma_{12}$ ( ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$) S-wave  $(3.8\pm{0.5})\times 10^{-3}$ 428
$\Gamma_{13}$ ${{\mathit \pi}^{\mp}}{{\mathit \rho}^{\pm}}$  $(7.4\pm{2.3})\times 10^{-4}$ 106
$\Gamma_{14}$ ${{\mathit \pi}^{0}}{{\mathit \rho}^{0}}$  $<4\%$ CL=90%111
$\Gamma_{15}$ 2( ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$)  $(8.4\pm{0.9})\times 10^{-5}$ 372
$\Gamma_{16}$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$2 ${{\mathit \pi}^{0}}$  $(1.8\pm{0.4})\times 10^{-4}$ 376
$\Gamma_{17}$ 2( ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$) neutrals  $<1\%$ CL=95%
$\Gamma_{18}$ 2( ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$) ${{\mathit \pi}^{0}}$  $<1.8\times 10^{-3}$ CL=90%298
$\Gamma_{19}$ 2( ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$) 2 ${{\mathit \pi}^{0}}$  $<1\%$ CL=95%197
$\Gamma_{20}$ 3( ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$)  $<3.1\times 10^{-5}$ CL=90%189
$\Gamma_{21}$ ${{\mathit K}^{\pm}}{{\mathit \pi}^{\mp}}$  $<4\times 10^{-5}$ CL=90%334
$\Gamma_{22}$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit e}^{+}}{{\mathit e}^{-}}$  $(2.4^{+1.3}_{-1.0})\times 10^{-3}$ 458
$\Gamma_{23}$ ${{\mathit \pi}^{+}}{{\mathit e}^{-}}{{\mathit \nu}_{{e}}}$ + c.c.  $<2.1\times 10^{-4}$ CL=90%469
$\Gamma_{24}$ ${{\mathit \gamma}}{{\mathit e}^{+}}{{\mathit e}^{-}}$  $(4.91\pm{0.27})\times 10^{-4}$ 479
$\Gamma_{25}$ ${{\mathit \pi}^{0}}{{\mathit \gamma}}{{\mathit \gamma}}$  $(3.20\pm{0.24})\times 10^{-3}$ 469
$\Gamma_{26}$ ${{\mathit \pi}^{0}}{{\mathit \gamma}}{{\mathit \gamma}}$ (non resonant)  $(6.2\pm{0.9})\times 10^{-4}$
$\Gamma_{27}$ ${{\mathit \eta}}{{\mathit \gamma}}{{\mathit \gamma}}$  $<1.33\times 10^{-4}$ CL=90%322
$\Gamma_{28}$ 4 ${{\mathit \pi}^{0}}$  $<3.2\times 10^{-4}$ CL=90%380
$\Gamma_{29}$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$  $<5.6\times 10^{-9}$ CL=90%479
$\Gamma_{30}$ invisible  $<6\times 10^{-4}$ CL=90%
    constrained fit information