${{\mathit \Omega}}$ BARYONS
($\mathit S$ = $-3$, $\mathit I$ = 0)
${{\mathit \Omega}^{-}}$ = ${\mathit {\mathit s}}$ ${\mathit {\mathit s}}$ ${\mathit {\mathit s}}$

${{\mathit \Omega}^{-}}$

$I(J^P)$ = $0(3/2^{+})$ 
The unambiguous discovery in both production and decay was by BARNES 1964. The quantum numbers follow from the assignment of the particle to the baryon decuplet. DEUTSCHMANN 1978 and BAUBILLIER 1978 rule out $\mathit J = 1/2$ and find consistency with $\mathit J = 3/2$. AUBERT,BE 2006 finds from the decay angular distributions of ${{\mathit \Xi}_{{{c}}}^{0}}$ $\rightarrow$ ${{\mathit \Omega}^{-}}{{\mathit K}^{+}}$ and ${{\mathit \Omega}_{{{c}}}^{0}}$ $\rightarrow$ ${{\mathit \Omega}^{-}}{{\mathit K}^{+}}$ that $\mathit J = 3/2$; this depends on the spins of the ${{\mathit \Xi}_{{{c}}}^{0}}$ and ${{\mathit \Omega}_{{{c}}}^{0}}$ being $\mathit J = 1/2$, their supposed values. ABLIKIM 2021E determines the ${{\mathit \Omega}^{-}}$ spin to be $\mathit J = 3/2$ from the decay angular distributions of the complete decay chain ${{\mathit \psi}{(3686)}}$ $\rightarrow$ ${{\mathit \Omega}^{-}}{{\overline{\mathit \Omega}}^{+}}$, with subsequent decays ${{\mathit \Omega}^{-}}$ $\rightarrow$ ${{\mathit K}^{-}}{{\mathit \Lambda}}$ and ${{\overline{\mathit \Omega}}^{+}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\overline{\mathit \Lambda}}}$. We have omitted some results that have been superseded by later experiments. See our earlier editions.
${{\mathit \Omega}^{-}}$ MASS   $1672.45 \pm0.29$ MeV 
${{\overline{\mathit \Omega}}^{+}}$ MASS   $1672.45 \pm0.29$ MeV 
(${\mathit m}_{{{\mathit \Omega}^{-}}}–{\mathit m}_{{{\overline{\mathit \Omega}}^{+}}}$) $/$ ${\mathit m}_{{{\mathit \Omega}^{-}}}$   $(-1 \pm8) \times 10^{-5}$  
${{\mathit \Omega}^{-}}$ MEAN LIFE   $(8.21 \pm0.11) \times 10^{-11}$ s 
${{\overline{\mathit \Omega}}^{+}}$ MEAN LIFE   $(8.21 \pm0.11) \times 10^{-11}$ s 
(${\mathit \tau}_{{{\mathit \Omega}^{-}}}–{\mathit \tau}_{{{\overline{\mathit \Omega}}^{+}}}$) $/$ ${\mathit \tau}_{{{\mathit \Omega}^{-}}}$   $0.00 \pm0.05$  
${{\mathit \Omega}^{-}}$ MAGNETIC MOMENT   $-2.02 \pm0.05$ $\mu _{\mathit N}$ 
${{\mathit \Omega}^{-}}$ DECAY PARAMETERS
$\alpha\mathrm {({{\mathit \Omega}^{-}})}$ $\alpha _{−}({{\mathit \Lambda}}$) FOR ${{\mathit \Omega}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit K}^{-}}$   $0.0115 \pm0.0015$  
$\alpha $ FOR ${{\mathit \Omega}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit K}^{-}}$   $0.0154 \pm0.0020$  
$\bar\alpha$ FOR ${{\overline{\mathit \Omega}}^{+}}$ $\rightarrow$ ${{\overline{\mathit \Lambda}}}{{\mathit K}^{+}}$   $-0.018 \pm0.004$  
($\alpha $ + $\bar\alpha)/(\alpha −\bar\alpha$) in ${{\mathit \Omega}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit K}^{-}}$, ${{\overline{\mathit \Omega}}^{+}}$ $\rightarrow$ ${{\overline{\mathit \Lambda}}}{{\mathit K}^{+}}$   $-0.02 \pm0.13$  
$\alpha $ FOR ${{\mathit \Omega}^{-}}$ $\rightarrow$ ${{\mathit \Xi}^{0}}{{\mathit \pi}^{-}}$   $0.09 \pm0.14$  
$\alpha $ FOR ${{\mathit \Omega}^{-}}$ $\rightarrow$ ${{\mathit \Xi}^{-}}{{\mathit \pi}^{0}}$   $0.05 \pm0.21$  
$\Gamma_{1}$ ${{\mathit \Lambda}}{{\mathit K}^{-}}$   $(67.7\pm{0.7})\%$ 211
$\Gamma_{2}$ ${{\mathit \Xi}^{0}}{{\mathit \pi}^{-}}$   $(24.3\pm{0.7})\%$ S=1.5  294
$\Gamma_{3}$ ${{\mathit \Xi}^{-}}{{\mathit \pi}^{0}}$   $(8.55\pm{0.33})\%$ 289
$\Gamma_{4}$ ${{\mathit \Xi}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$   $(3.7^{+0.7}_{-0.6})\times 10^{-4}$ 189
$\Gamma_{5}$ ${{\mathit \Xi}{(1530)}^{0}}{{\mathit \pi}^{-}}$   $<7\times 10^{-5}$ CL=90% 17
$\Gamma_{6}$ ${{\mathit \Xi}^{0}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{{e}}}}$   $(5.6\pm{2.8})\times 10^{-3}$ 319
$\Gamma_{7}$ ${{\mathit \Xi}^{-}}{{\mathit \gamma}}$   $<4.6\times 10^{-4}$ CL=90% 314