${{\boldsymbol \Sigma}}$ BARYONS
($\boldsymbol S$ = $-1$, $\boldsymbol I$ = 1)
${{\mathit \Sigma}^{+}}$ = ${\mathit {\mathit u}}$ ${\mathit {\mathit u}}$ ${\mathit {\mathit s}}$, ${{\mathit \Sigma}^{0}}$ = ${\mathit {\mathit u}}$ ${\mathit {\mathit d}}$ ${\mathit {\mathit s}}$, ${{\mathit \Sigma}^{-}}$ = ${\mathit {\mathit d}}$ ${\mathit {\mathit d}}$ ${\mathit {\mathit s}}$
INSPIRE search

${{\boldsymbol \Sigma}^{+}}$ $I(J^P)$ = $1(1/2^{+})$

We have omitted some results that have been superseded by later experiments. See our earlier editions.
${{\mathit \Sigma}^{+}}$ MASS   $1189.37 \pm0.07$ MeV (S = 2.2)
${{\mathit \Sigma}^{+}}$ MEAN LIFE   $(8.018 \pm0.026) \times 10^{-11}$ s 
(${\mathit \tau}_{{{\mathit \Sigma}^{+}}}–{\mathit \tau}_{{{\overline{\mathit \Sigma}}^{-}}}$) $/$ ${\mathit \tau}_{{{\mathit \Sigma}^{+}}}$   $-0.0006 \pm0.0012$  
${{\mathit \Sigma}^{+}}$ MAGNETIC MOMENT   $2.458 \pm0.010$ $\mu _{\mathit N}$ (S = 2.1)
(${\mathit \mu}_{{{\mathit \Sigma}^{+}}}$ $+$ ${\mathit \mu}_{{{\overline{\mathit \Sigma}}^{-}}}$) $/$ ${\mathit \mu}_{{{\mathit \Sigma}^{+}}}$   $0.014 \pm0.015$  
${{\boldsymbol \Sigma}^{+}}$ DECAY PARAMETERS
$\alpha _{0}$ FOR ${{\mathit \Sigma}^{+}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \pi}^{0}}$   $-0.980 {}^{+0.017}_{-0.015}$  
$\phi _{0}$ ANGLE FOR ${{\mathit \Sigma}^{+}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \pi}^{0}}$ ($\phi _{0}$ = $\beta /\gamma $)   $36 \pm34$ $^\circ{}$ 
$\alpha _{+}$ $/$ $\alpha _{0}$   $-0.069 \pm0.013$  
$\alpha _{+}$ FOR ${{\mathit \Sigma}^{+}}$ $\rightarrow$ ${{\mathit n}}{{\mathit \pi}^{+}}$   $0.068 \pm0.013$  
$\phi _{+}$ ANGLE FOR ${{\mathit \Sigma}^{+}}$ $\rightarrow$ ${{\mathit n}}{{\mathit \pi}^{+}}$ ($\phi _{+}$ = $\beta /\gamma $)   $167 \pm20$ $^\circ{}$ (S = 1.1)
$\alpha _{\gamma }$ FOR ${{\mathit \Sigma}^{+}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \gamma}}$   $-0.76 \pm0.08$  
$\Gamma_{1}$ ${{\mathit p}}{{\mathit \pi}^{0}}$ $(51.57\pm{0.30})\%$189
$\Gamma_{2}$ ${{\mathit n}}{{\mathit \pi}^{+}}$ $(48.31\pm{0.30})\%$185
$\Gamma_{3}$ ${{\mathit p}}{{\mathit \gamma}}$ $(1.23\pm{0.05})\times 10^{-3}$225
$\Gamma_{4}$ ${{\mathit n}}{{\mathit \pi}^{+}}{{\mathit \gamma}}$ [1]$(4.5\pm{0.5})\times 10^{-4}$185
$\Gamma_{5}$ ${{\mathit \Lambda}}{{\mathit e}^{+}}{{\mathit \nu}_{{e}}}$ $(2.0\pm{0.5})\times 10^{-5}$71
    constrained fit information