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

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

$\phi $ ANGLE FOR ${{\mathit \Xi}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \pi}^{-}}$ (tan$\phi $ = $\beta /\gamma $)

INSPIRE   PDGID:
S022F
VALUE ($^\circ{}$) EVTS DOCUMENT ID TECN  COMMENT
$\bf{ -1.2 \pm1.0}$ OUR AVERAGE  Error includes scale factor of 1.4.  See the ideogram below.
$0.63$ $\pm1.09$ $\pm0.52$ 73k 1
ABLIKIM
2022AD
 BES3 ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \Xi}}{{\overline{\mathit \Xi}}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\overline{\mathit \Lambda}}}{{\mathit \pi}}{{\mathit \pi}}$
$-2.39$ $\pm0.64$ $\pm0.64$ 144M 2
HUANG
2004
HYCP ${{\mathit p}}$ Cu, 800 GeV
$-1.61$ $\pm2.66$ $\pm0.37$ 1.35M 3
CHAKRAVORTY
2003
E756 ${{\mathit p}}$ Be, 800 GeV
$5$ $\pm10$ 11k
ASTON
1985B
 LASS ${{\mathit K}^{-}}{{\mathit p}}$
$14.7$ $\pm16.0$ 21k 4
BENSINGER
1985
MPS 5 ${\mathrm {GeV/}}\mathit c$ ${{\mathit K}^{-}}{{\mathit p}}$
$11$ $\pm9$ 4303
BALTAY
1974
HBC 1.75 ${\mathrm {GeV/}}\mathit c$ ${{\mathit K}^{-}}{{\mathit p}}$
$5$ $\pm16$ 2436
COOL
1974
OSPK 1.8 ${\mathrm {GeV/}}\mathit c$ ${{\mathit K}^{-}}{{\mathit p}}$
$-14$ $\pm11$ 2781
DAUBER
1969
HBC Uses $\alpha _{{{\mathit \Lambda}}}$ = $0.647$ $\pm0.020$
$0$ $\pm12$ 1004 5
BERGE
1966
HBC
• • We do not use the following data for averages, fits, limits, etc. • •
$1.32$ $\pm4.24$ $\pm0.17$ 5.4k 6
ABLIKIM
2022BE
 BES3 ${{\mathit \psi}{(3686)}}$ $\rightarrow$ ${{\mathit \Xi}}{{\overline{\mathit \Xi}}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\overline{\mathit \Lambda}}}{{\mathit \pi}}{{\mathit \pi}}$
$-26$ $\pm30$ 2724
BINGHAM
1970B
 OSPK
$0$ $\pm20.4$ 364 5
LONDON
1966
HBC Using $\alpha _{{{\mathit \Lambda}}}=0.62$
$54$ $\pm30$ 356 5
CARMONY
1964B
 HBC
1  Converted from radians to degrees. ABLIKIM 2022AD reports a value of $0.011$ $\pm0.019$ $\pm0.009$ radians.
2  From this result and $\alpha _{{{\mathit \Xi}}}$, HUANG 2004 gets $\beta _{{{\mathit \Xi}}}$ = $-0.037$ $\pm0.011$ $\pm0.010$ and $\gamma _{{{\mathit \Xi}}}$ = $0.888$ $\pm0.0004$ $\pm0.006$. And the strong p$-$s phase difference for ${{\mathit \Lambda}}{{\mathit \pi}^{-}}$ scattering is ($4.6$ $\pm1.4$ $\pm1.2)^\circ{}$.
3  From this result and $\alpha _{{{\mathit \Xi}}}$, CHAKRAVORTY 2003 obtains $\beta _{{{\mathit \Xi}}}$ = $-0.025$ $\pm0.042$ $\pm0.006$ and $\gamma _{{{\mathit \Xi}}}$ = $0.889$ $\pm0.001$ $\pm0.007$. And the strong p$-$s phase difference for ${{\mathit \Lambda}}{{\mathit \pi}^{-}}$ scattering is ($3.17$ $\pm5.28$ $\pm0.73)^\circ{}$.
4  BENSINGER 1985 used $\alpha _{\Lambda }$ = $0.642$ $\pm0.013$.
5  The errors have been multiplied by 1.2 due to approximations used for the ${{\mathit \Xi}}$ polarization; see DAUBER 1969 for a discussion.
6  Converted from radians to degrees. ABLIKIM 2022BE reports a value of $0.023$ $\pm0.074$ $\pm0.003$ radians.

           $\phi $ ANGLE FOR ${{\mathit \Xi}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \pi}^{-}}$ (tan$\phi $ = $\beta /\gamma $) ($^\circ{}$)
References:
ABLIKIM 2022AD
NAT 606 64 Probing CP symmetry and weak phases with entangled double-strange baryons
ABLIKIM 2022BE
PR D106 L091101 Observation of ?- hyperon transverse polarization in ?(3686)??-?¯+
HUANG 2004
PRL 93 011802 New Measurement of ${{\mathit \Xi}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \pi}^{-}}$ Decay Parameters
CHAKRAVORTY 2003
PRL 91 031601 Measurement of Decay Parameters for ${{\mathit \Xi}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \pi}^{-}}$ Decay
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
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
BINGHAM 1970B
PR D1 3010 Study of the Decay Parameters and Magnetic Moment of the ${{\mathit \Xi}^{-}}$
DAUBER 1969
PR 179 1262 Production and Decay of Cascade Hyperons
BERGE 1966
PR 147 945 Some Properties of ${{\mathit \Xi}^{-}}$ and ${{\mathit \Xi}^{0}}$ Hyperons Produced in ${{\mathit K}^{-}}{{\mathit p}}$ Interactions between 1.05 and 1.7 ${\mathrm {GeV/}}\mathit c$
LONDON 1966
PR 143 1034 ${{\mathit K}^{-}}{{\mathit p}}$ Interaction at 2.24 BeV
CARMONY 1964B
PRL 12 482 Properties of ${{\mathit \Xi}}$ Hyperons