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${{\mathit \Sigma}}$ 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  (beta) 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We have omitted some results that have been superseded by later experiments.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.

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

${{\mathit \Sigma}^{-}}$ 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 ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit n}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$   $0.97 \pm0.14$

TRIPLE CORRELATION COEFFICIENT $\mathit D$ for ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit n}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$   $0.11 \pm0.10$

see data

${\mathit g}_{{{\mathit V}}}/{\mathit g}_{{{\mathit A}}}$ 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 ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$   $2.4 \pm1.7$

${{\mathit \Sigma}^{-}}$ DECAY MODES ▸  Expand all decays
Mode   Fraction ($\Gamma_i$ / $\Gamma$) Scale Factor/ Conf. Level P(MeV/c)   $\Gamma_{1}$ ${{\mathit n}}{{\mathit \pi}^{-}}$   $(99.848\pm{0.005})\%$ 193   $\Gamma_{2}$ ${{\mathit n}}{{\mathit \pi}^{-}}{{\mathit \gamma}}$  [1] $(4.6\pm{0.6})\times 10^{-4}$ 193   $\Gamma_{3}$ ${{\mathit n}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$   $(1.017\pm{0.034})\times 10^{-3}$ 230   $\Gamma_{4}$ ${{\mathit n}}{{\mathit \mu}^{-}}{{\overline{\mathit \nu}}_{{\mu}}}$   $(4.5\pm{0.4})\times 10^{-4}$ 210   $\Gamma_{5}$ ${{\mathit \Lambda}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$   $(5.73\pm{0.27})\times 10^{-5}$ 79   $\Gamma_{6}$ ${{\mathit \Sigma}^{+}}{{\mathit X}}$   $<1.2\times 10^{-4}$ CL=90%     ▸ Lepton number ($\mathit L$) violating modes
FOOTNOTES

Constrained Fit information