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

${{\boldsymbol a}_{{0}}{(980)}}$ $I^G(J^{PC})$ = $1^-(0^{+ +})$ 

See our minireview on scalar mesons under ${{\mathit f}_{{0}}{(500)}}$. (See the index for the page number.)
${{\boldsymbol a}_{{0}}{(980)}}$ MASS
Mass $\mathit m$   $980 \pm20$ MeV 
${{\mathit \eta}}{{\mathit \pi}}$ FINAL STATE ONLY
${{\mathit K}}{{\overline{\mathit K}}}$ ONLY
${{\boldsymbol a}_{{0}}{(980)}}$ WIDTH
Full width $\Gamma $   $50\text{ to }100 $ MeV 
${{\mathit K}}{{\overline{\mathit K}}}$ ONLY   $92 \pm8$ MeV 
$\Gamma_{1}$ ${{\mathit \eta}}{{\mathit \pi}}$ seen319
$\Gamma_{2}$ ${{\mathit K}}{{\overline{\mathit K}}}$ seen-1
$\Gamma_{3}$ ${{\mathit \rho}}{{\mathit \pi}}$ not seen137
$\Gamma_{4}$ ${{\mathit \gamma}}{{\mathit \gamma}}$ seen490
$\Gamma_{5}$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ 490