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${{\mathit \Xi}}$ DECAY PARAMETERS

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

$\alpha\mathrm {({{\mathit \Xi}^{-}})}{}\alpha _{−}({{\mathit \Lambda}}$)

INSPIRE   PDGID:

S022AA

OUR FIT value is obtained from measurements of $\alpha\mathrm {({{\mathit \Xi}^{-}})}$, $\alpha _{−}({{\mathit \Lambda}}$), and $\alpha\mathrm {({{\mathit \Xi}^{-}})}{}\alpha _{−}({{\mathit \Lambda}}$).

VALUE EVTS DOCUMENT ID TECN  COMMENT $\bf{ -0.2914 \pm0.0033}$ OUR FIT  Error includes scale factor of 1.4. $\bf{ -0.294 \pm0.005}$ OUR AVERAGE  Error includes scale factor of 1.7.  See the ideogram below. $-0.2963$ $\pm0.0042$ 189k LUK 2000 E756 ${{\mathit p}}$ Be, 800 GeV $-0.2894$ $\pm0.0073$ 63k 1 LUK 2000 E756 ${{\mathit p}}$ Be, 800 GeV $-0.303$ $\pm0.004$ $\pm0.004$ 192k RAMEIKA 1986 SPEC 400 GeV ${{\mathit p}}{}^{}\mathrm {Be}$ $-0.257$ $\pm0.020$ 11k ASTON 1985 B LASS 11 ${\mathrm {GeV/}}\mathit c$ ${{\mathit K}^{-}}{{\mathit p}}$ $-0.260$ $\pm0.017$ 21k BENSINGER 1985 MPS 5 ${\mathrm {GeV/}}\mathit c$ ${{\mathit K}^{-}}{{\mathit p}}$ $-0.299$ $\pm0.007$ 150k BIAGI 1982 SPEC SPS hyperon beam $-0.315$ $\pm0.026$ 9046 CLELAND 1980 C ASPK BNL hyperon beam $-0.239$ $\pm0.021$ 6599 HEMINGWAY 1978 HBC 4.2 ${\mathrm {GeV/}}\mathit c$ ${{\mathit K}^{-}}{{\mathit p}}$ $-0.243$ $\pm0.025$ 4303 BALTAY 1974 HBC 1.75 ${\mathrm {GeV/}}\mathit c$ ${{\mathit K}^{-}}{{\mathit p}}$ $-0.252$ $\pm0.032$ 2436 COOL 1974 OSPK 1.8 ${\mathrm {GeV/}}\mathit c$ ${{\mathit K}^{-}}{{\mathit p}}$ $-0.253$ $\pm0.028$ 2781 DAUBER 1969 HBC 1  This LUK 2000 value is for $\alpha\mathrm {({{\overline{\mathit \Xi}}^{+}})}$ $\alpha _{+}({{\overline{\mathit \Lambda}}}$). We assume $\mathit CP$ conservation here by including it in the average for $\alpha\mathrm {({{\mathit \Xi}^{-}})}$ $\alpha _{−}({{\mathit \Lambda}}$). But see the second data block below for the $\mathit CP$ test.

$\alpha\mathrm {({{\mathit \Xi}^{-}})}{}\alpha _{−}({{\mathit \Lambda}}$)

References:

LUK 2000 PRL 85 4860 Search for Direct $\mathit CP$ Violation in Nonleptonic Decays of Charged ${{\mathit \Xi}}$ and ${{\mathit \Lambda}}$ Hyperons RAMEIKA 1986 PR D33 3172 Measurement of Production Polarization and Decay Asymmetry for ${{\mathit \Xi}^{-}}$ Hyperons ASTON 1985B PR D32 2270 Inclusive Production of Multistrange Hyperons from 11 ${\mathrm {GeV/}}\mathit c$ ${{\mathit K}^{-}}{{\mathit p}}$ Interactions BENSINGER 1985 NP B252 561 Measurement of Decay Parameters and Polarization in Inclusive ${{\mathit \Xi}^{-}}$ Production from ${{\mathit K}^{-}}{{\mathit p}}$ Interactions BIAGI 1982 PL 112B 265 Determination of the $\alpha $ Parameter for the Decay ${{\mathit \Xi}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \pi}^{-}}$ CLELAND 1980C PR D21 12 Studies in the BNL 21 ${\mathrm {GeV/}}\mathit c$ Negative Hyperon Beam. I. ${{\mathit \Sigma}}$ and ${{\mathit \Xi}}$ Production and Asymmetry in Decay ${{\mathit \Xi}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \pi}^{-}}$ HEMINGWAY 1978 NP B142 205 ${{\mathit \Omega}^{-}}$ Produced in ${{\mathit K}^{-}}{{\mathit p}}$ Reactions at 4.2 ${\mathrm {GeV/}}\mathit c$ BALTAY 1974 PR D9 49 Properties of ${{\mathit \Xi}^{-}}$ and ${{\mathit \Xi}^{0}}$ Hyperons COOL 1974 PR D10 792 Measurement of the Magnetic Moment and of the Decay Parameters of the ${{\mathit \Xi}^{-}}$ Hyperon Also PRL 29 1630 Measurement of the ${{\mathit \Xi}^{-}}$ Magnetic Moment DAUBER 1969 PR 179 1262 Production and Decay of Cascade Hyperons

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