${{\boldsymbol \Sigma}^{-}}$ DECAY PARAMETERS

See the ``Note on Baryon Decay Parameters'' in the neutron Listings. Older, outdated results have been omitted.

${\boldsymbol g}_{{{\boldsymbol A}}}/{\boldsymbol g}_{{{\boldsymbol V}}}$ FOR ${{\boldsymbol \Sigma}^{-}}$ $\rightarrow$ ${{\boldsymbol n}}{{\boldsymbol e}^{-}}{{\overline{\boldsymbol \nu}}_{{e}}}$ INSPIRE search

Measurements with fewer than 500 events have been omitted. Where necessary, signs have been changed to agree with our conventions, which are given in the ``Note on Baryon Decay Parameters'' in the neutron Listings. What is actually listed is $\vert \mathit g_{1}/\mathit f_{1}-0.237\mathit g_{2}/\mathit f_{1}\vert $. This reduces to ${\mathit g}_{{{\mathit A}}}/{\mathit g}_{{{\mathit V}}}{}\equiv$ $\mathit g_{1}(0)/\mathit f_{1}$(0) on making the usual assumption that $\mathit g_{2}$ = 0. See also the note on HSUEH 1988 .
VALUE EVTS DOCUMENT ID TECN  COMMENT
$\bf{ 0.340 \pm0.017}$ OUR AVERAGE
$+0.327$ $\pm0.007$ $\pm0.019$ 50k 1
HSUEH
1988
SPEC ${{\mathit \Sigma}^{-}}$ 250 GeV
$+0.34$ $\pm0.05$ 4456 2
BOURQUIN
1983C
SPEC SPS hyperon beam
$0.385$ $\pm0.037$ 3507 3
TANENBAUM
1974
ASPK
• • • We do not use the following data for averages, fits, limits, etc. • • •
$0.29$ $\pm0.07$ 25k
HSUEH
1985
SPEC See HSUEH 1988
$0.17$ ${}^{+0.07}_{-0.09}$ 519
DECAMP
1977
ELEC Hyperon beam
1  The sign is, $\mathit with~our~conventions$, unambiguously positive. The value assumes, as usual, that $\mathit g_{2}$ = 0. If $\mathit g_{2}$ is included in the fit, than (with our sign convention) $\mathit g_{2}$ = $-0.56$ $\pm0.37$, with a corresponding reduction of ${\mathit g}_{{{\mathit A}}}/{\mathit g}_{{{\mathit V}}}$ to $+0.20$ $\pm0.08$.
2  BOURQUIN 1983C favors the positive sign by at least 2.6 standard deviations.
3  TANENBAUM 1974 gives $0.435$ $\pm0.035$, assuming no $\mathit q{}^{2}$ dependence in $\mathit g_{\mathit A}$ and ${\mathit g}_{{{\mathit V}}}$. The listed result allows $\mathit q{}^{2}$ dependence, and is taken from HSUEH 1988 .
  References:
HSUEH 1988
PR D38 2056 High Precision Measurement of Polarized ${{\mathit \Sigma}^{-}}$ $\beta $ Decay
HSUEH 1985
PRL 54 2399 Measurement of the Electron Asymmetry in the $\beta $ Decay of Polarized ${{\mathit \Sigma}^{-}}$ Hyperons
BOURQUIN 1983C
ZPHY C21 17 Measurements of Hyperon Semileptonic Decays at the CERN Super Proton Synchrotron. 3. The ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit n}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$ Decay Mode
DECAMP 1977
PL 66B 295 The Ratio $\mathit g_{a}$/g$_{v}$ in the Decay ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit n}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$
TANENBAUM 1974
PRL 33 175 |$\mathit g_{a}$/g$_{v}$| in the Decay ${{\mathit \Sigma}^{-}}$ $\rightarrow$ ${{\mathit n}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}}$