${{\mathit \Omega}}$ 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 We have omitted some results that have been superseded by later experiments.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 ${{\mathit \Omega}^{-}}$ $\rightarrow$ ${{\mathit \Xi}^{-}}{{\mathit \pi}^{0}}$   $0.05 \pm0.21$  
$\Gamma_{1}$ ${{\mathit \Lambda}}{{\mathit K}^{-}}$   $(67.8\pm{0.7})\%$ 211
$\Gamma_{2}$ ${{\mathit \Xi}^{0}}{{\mathit \pi}^{-}}$   $(23.6\pm{0.7})\%$ 294
$\Gamma_{3}$ ${{\mathit \Xi}^{-}}{{\mathit \pi}^{0}}$   $(8.6\pm{0.4})\%$ 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