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

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

We have omitted some results that have been superseded by later experiments. See our earlier editions.

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

$1197.449 \pm0.030$ MeV (S = 1.2)

${\mathit m}_{{{\mathit \Sigma}^{-}}}–{\mathit m}_{{{\mathit \Sigma}^{+}}}$

$8.08 \pm0.08$ MeV (S = 1.9)

${\mathit m}_{{{\mathit \Sigma}^{-}}}–{\mathit m}_{{{\mathit \Lambda}}}$

$81.766 \pm0.030$ MeV (S = 1.2)

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

${{\boldsymbol \Sigma}^{-}}$ DECAY PARAMETERS

$\alpha _{−}$ FOR ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit n}}{{\mathit \pi}^{-}}$

$-0.068 \pm0.008$

$\phi $ ANGLE FOR ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit n}}{{\mathit \pi}^{-}}$ (tan$\phi $ = $\beta $ $/$ $\gamma $)

$10 \pm15$ $^\circ{}$

${\mathit g}_{{{\mathit A}}}/{\mathit g}_{{{\mathit V}}}$ FOR ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit n}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$

$0.340 \pm0.017$

$\mathit f_{2}(0)/\mathit f_{1}$(0) FOR ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit n}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$

TRIPLE CORRELATION COEFFICIENT $\mathit D$ for ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit n}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$

${\mathit g}_{{{\mathit V}}}/{\mathit g}_{{{\mathit A}}}$ FOR ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$

$0.01 \pm0.10$ (S = 1.5)

${\mathit g}_{\mathit WM}/{\mathit g}_{{{\mathit A}}}$ FOR ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$

Decay Modes

${{\mathit n}}{{\mathit \pi}^{-}}$

$(99.848\pm{0.005})\%$

${{\mathit n}}{{\mathit \pi}^{-}}{{\mathit \gamma}}$

$(4.6\pm{0.6})\times 10^{-4}$

${{\mathit n}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$

$(1.017\pm{0.034})\times 10^{-3}$

${{\mathit n}}{{\mathit \mu}^{-}}{{\overline{\mathit \nu}}_{{\mu}}}$

$(4.5\pm{0.4})\times 10^{-4}$

${{\mathit \Lambda}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$

$(5.73\pm{0.27})\times 10^{-5}$

constrained fit information