${{\mathit \Sigma}}$ 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:
S020

${{\mathit \Sigma}^{-}}$

$I(J^P)$ = $1(1/2^{+})$ 
We have omitted some results that have been superseded by later experiments. See our earlier editions.
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${{\mathit \Sigma}^{-}}$ MASS $1197.449$ $\pm0.029$ MeV (S = 1.1)
 
${\mathit m}_{{{\mathit \Sigma}^{-}}}-{\mathit m}_{{{\mathit \Sigma}^{+}}}$ $8.08$ $\pm0.08$ MeV (S = 1.9)
 
${\mathit m}_{{{\mathit \Sigma}^{-}}}-{\mathit m}_{{{\mathit \Lambda}}}$ $81.69$ $\pm0.07$ MeV 
 
${{\mathit \Sigma}^{-}}$ MEAN LIFE ($1.479$ $\pm0.011$) $ \times 10^{-10}$ s (S = 1.3)
 
${{\mathit \Sigma}^{-}}$ MAGNETIC MOMENT $-1.160$ $\pm0.025$ $\mu _{\mathit N}$ (S = 1.7)
 
${{\mathit \Sigma}^{-}}$ CHARGE RADIUS $0.78$ $\pm0.10$ fm 
 
▸  ${{\mathit \Sigma}^{-}}$ DECAY PARAMETERS
Mode  
Fraction ($\Gamma_i$ / $\Gamma$) Scale Factor/
Conf. Level		 P(MeV/c)  
$\Gamma_{1}$ ${{\mathit n}}{{\mathit \pi}^{-}}$ ($99.848$ $\pm0.005$ ) $\%$ 193
 
$\Gamma_{2}$ ${{\mathit n}}{{\mathit \pi}^{-}}{{\mathit \gamma}}$ [2] ($4.6$ $\pm0.6$) $ \times 10^{-4}$ 193
 
$\Gamma_{3}$ ${{\mathit n}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{{e}}}}$ ($1.017$ $\pm0.034$) $ \times 10^{-3}$ 230
 
$\Gamma_{4}$ ${{\mathit n}}{{\mathit \mu}^{-}}{{\overline{\mathit \nu}}_{{{\mu}}}}$ ($4.5$ $\pm0.4$) $ \times 10^{-4}$ 210
 
$\Gamma_{5}$ ${{\mathit \Lambda}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{{e}}}}$ ($5.73$ $\pm0.27$) $ \times 10^{-5}$ 79
 
$\Gamma_{6}$ ${{\mathit \Sigma}^{+}}{{\mathit X}}$ $<1.2$ $\times 10^{-4}$ CL=90%  
 
▸  Lepton number ($\mathit L$) violating modes
[1] The parameters ${\mathit g}_{{{\mathit A}}}$, ${\mathit g}_{{{\mathit V}}}$, and ${\mathit g}_{\mathit WM}$ for semileptonic modes are defined by ${{\overline{\mathit B}}_{{{f}}}}[{{\mathit \gamma}_{{{\lambda}}}}({\mathit g}_{{{\mathit V}}}$ $+$ ${\mathit g}_{{{\mathit A}}}{{\mathit \gamma}_{{{5}}}}$) $+$ $\mathit i({\mathit g}_{\mathit WM}/{\mathit m}_{{{\mathit B}_{{{i}}}}}$) $\sigma _{\lambda \nu }$ $\mathit q{}^{\nu }]\mathit B_{\mathit i}$, and $\phi _{\mathit AV}$ is defined by ${\mathit g}_{{{\mathit A}}}/{\mathit g}_{{{\mathit V}}}$ = $\vert {\mathit g}_{{{\mathit A}}}/{\mathit g}_{{{\mathit V}}}\vert \mathit e{}^{\mathit i\phi _{\mathit AV}}$. See the ``Note on Baryon Decay Parameters'' in the neutron Particle Listings.
[2] See the Listings below for the pion momentum range used in this measurement.
Constrained Fit information