${{\mathit \Lambda}_{{{c}}}^{+}}$ DECAY PARAMETERS

See the review on ``Baryon Decay Parameters.''

$\alpha $ FOR ${{\mathit \Lambda}_{{{c}}}^{+}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \pi}^{+}}$

INSPIRE   PDGID:
S033A
VALUE EVTS DOCUMENT ID TECN  COMMENT
$\bf{ -0.755 \pm0.006}$ OUR AVERAGE
$-0.755$ $\pm0.005$ $\pm0.003$ 264k 1
LI
2023C
 BELL ${{\mathit e}^{+}}{{\mathit e}^{-}}$ at/near ${{\mathit \Upsilon}{(nS)}}$, n=1,...,5
$-0.80$ $\pm0.11$ $\pm0.02$
ABLIKIM
2019AX
 BES3 ${{\mathit e}^{+}}{{\mathit e}^{-}}$ at 4.6 GeV
$-0.78$ $\pm0.16$ $\pm0.19$
LINK
2006A
 FOCS $\gamma $ A, ${{\overline{\mathit E}}}_{\gamma }${} $\approx{}$ 180 GeV
$-0.94$ $\pm0.21$ $\pm0.12$ 414 2
BISHAI
1995
CLE2 ${{\mathit e}^{+}}{{\mathit e}^{-}}$ $\approx{}{{\mathit \Upsilon}{(4S)}}$
$-0.96$ $\pm0.42$
ALBRECHT
1992
ARG ${{\mathit e}^{+}}{{\mathit e}^{-}}$ $\approx{}10.4$ GeV
$-1.1$ $\pm0.4$ 86
AVERY
1990B
 CLEO ${{\mathit e}^{+}}{{\mathit e}^{-}}$ $\approx{}10.6$ GeV
1  LI 2023C obtained the value by a fit for the product $\alpha $ ${\times }$ $\alpha {}^{avg}_{{{\mathit \Lambda}}}$, and dividing by the value $\alpha {}^{avg}_{{{\mathit \Lambda}}}$ = $0.7542$ $\pm0.0026$ reported in ABLIKIM 2022AG.
2  BISHAI 1995 actually gives $\alpha =-0.94$ ${}^{+0.21}_{-0.06}{}^{+0.12}_{-0.06}$, chopping the errors at the physical limit $-1.0$. However, for $\alpha \approx{}-1.0$, some experiments should $\mathit get$ unphysical values ($\alpha <-1.0$), and for averaging with other measurements such values (or errors that extend below $-1.0$) should $\mathit not$ be chopped.
References