# ${{\boldsymbol \Xi}^{-}}$ DECAY PARAMETERS

See the Note on Baryon Decay Parameters'' in the neutron Listings.

# ${[\alpha\mathrm {({{\boldsymbol \Xi}^{-}})}\alpha_-({{\boldsymbol \Lambda}}) − \alpha\mathrm {({{\overline{\boldsymbol \Xi}}^{+}})}\alpha_+({{\overline{\boldsymbol \Lambda}}})]\over [\alpha\mathrm {({{\boldsymbol \Xi}^{-}})}\alpha_-({{\boldsymbol \Lambda}}) + \alpha\mathrm {({{\overline{\boldsymbol \Xi}}^{+}})}\alpha_+({{\overline{\boldsymbol \Lambda}}})]}$ INSPIRE search

This is zero if $\mathit CP$ is conserved. The $\alpha$'s are the decay-asymmetry parameters for ${{\mathit \Xi}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \pi}^{-}}$ and ${{\mathit \Lambda}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \pi}^{-}}$ and for ${{\overline{\mathit \Xi}}^{+}}$ $\rightarrow$ ${{\overline{\mathit \Lambda}}}{{\mathit \pi}^{+}}$ and ${{\overline{\mathit \Lambda}}}$ $\rightarrow$ ${{\overline{\mathit p}}}{{\mathit \pi}^{+}}$ .
VALUE ($10^{-4}$) EVTS DOCUMENT ID TECN  COMMENT
$0.0$ $\pm5.1$ $\pm4.4$ 158M
 2004
HYCP ${{\mathit p}}$ Cu, 800 GeV
• • • We do not use the following data for averages, fits, limits, etc. • • •
$+120$ $\pm140$ 252k
 2000
E756 ${{\mathit p}}$ Be, 800 GeV
Conservation Laws:
 $\mathit CP$ INVARIANCE
References:
 HOLMSTROM 2004
PRL 93 262001 Search for $\mathit CP$ Violation in Charged-${{\mathit \Xi}}$ and ${{\mathit \Lambda}}$ Hyperon Decays
 LUK 2000
PRL 85 4860 Search for Direct $\mathit CP$ Violation in Nonleptonic Decays of Charged ${{\mathit \Xi}}$ and ${{\mathit \Lambda}}$ Hyperons