${{\mathit \Sigma}}$ BARYONS
($\mathit S$ = $-1$, $\mathit I$ = 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   JSON PDGID:
S019

${{\mathit \Sigma}^{+}}$

$I(J^P)$ = $1(1/2^{+})$ 
We have omitted some results that have been superseded by later experiments. See our earlier editions.
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${{\mathit \Sigma}^{+}}$ MASS $1189.37$ $\pm0.06$ MeV (S = 1.8)
 
${{\mathit \Sigma}^{+}}$ 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)
 
(${\mathit \mu}_{{{\mathit \Sigma}^{+}}}$ $+$ ${\mathit \mu}_{{{\overline{\mathit \Sigma}}^{-}}}$) $/$ ${\mathit \mu}_{{{\mathit \Sigma}^{+}}}$ $0.014$ $\pm0.015$  
 
▸  ${{\mathit \Sigma}^{+}}$ DECAY PARAMETERS
Mode  
Fraction ($\Gamma_i$ / $\Gamma$) Scale Factor/
Conf. Level
P(MeV/c)  
$\Gamma_{1}$ ${{\mathit p}}{{\mathit \pi}^{0}}$ ($51.47$ $\pm0.30$ ) $\%$ 189
 
$\Gamma_{2}$ ${{\mathit n}}{{\mathit \pi}^{+}}$ ($48.43$ $\pm0.30$ ) $\%$ 185
 
$\Gamma_{3}$ ${{\mathit p}}{{\mathit \gamma}}$ ($1.04$ $\pm0.06$) $ \times 10^{-3}$ S=2.4  225
 
$\Gamma_{4}$ ${{\mathit n}}{{\mathit \pi}^{+}}{{\mathit \gamma}}$ [1] ($4.5$ $\pm0.5$) $ \times 10^{-4}$ 185
 
$\Gamma_{5}$ ${{\mathit \Lambda}}{{\mathit e}^{+}}{{\mathit \nu}_{{{e}}}}$ ($2.3$ $\pm0.4$) $ \times 10^{-5}$ 71
 
▸  $\Delta \mathit S$ = $\Delta \mathit Q$ ($\mathit SQ$) violating modes or $\Delta \mathit S$ = 1 weak neutral current ($\mathit S1$) modes
[1] See the Listings below for the pion momentum range used in this measurement.
Constrained Fit information