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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  (beta) PDGID: M027

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

See also the ${{\mathit \eta}{(1475)}}$.

${{\mathit \eta}{(1405)}}$ 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)

${{\mathit \eta}{(1405)}}$ 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)

Decay Modes
Mode   Fraction ($\Gamma_i$ / $\Gamma$) Scale Factor/ Conf. Level P(MeV/c)   $\Gamma_{1}$ ${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}$   seen 424   $\Gamma_{2}$ ${{\mathit \eta}}{{\mathit \pi}}{{\mathit \pi}}$   seen 562   $\Gamma_{3}$ ${{\mathit a}_{{{0}}}{(980)}}{{\mathit \pi}}$   seen 345   $\Gamma_{4}$ ${{\mathit \eta}}{({\mathit \pi}{\mathit \pi})_{{{\mathit S}-{\text{wave}}}}}$   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 ${{\mathit \pi}}$   seen 639   $\Gamma_{8}$ ${{\mathit \rho}}{{\mathit \rho}}$   $<58\%$ CL=100% -1   $\Gamma_{9}$ ${{\mathit \gamma}}{{\mathit \gamma}}$   704   $\Gamma_{10}$ ${{\mathit \rho}^{0}}{{\mathit \gamma}}$   seen 491   $\Gamma_{11}$ ${{\mathit \phi}}{{\mathit \gamma}}$   336   $\Gamma_{12}$ ${{\mathit K}^{*}{(892)}}{{\mathit K}}$   seen 123
FOOTNOTES