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

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

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

INSPIRE   PDGID:
S033ALC
The experiments don't cover the complete (or same incomplete) $\mathit M({{\mathit \Lambda}}{{\mathit \ell}^{+}}$) range, but we average them together anyway.
VALUE EVTS DOCUMENT ID TECN  COMMENT
$\bf{ -0.875 \pm0.033}$ OUR AVERAGE
$-0.94$ $\pm0.07$ $\pm0.03$ 752 1
ABLIKIM
2023AT
 BES3 ${{\mathit e}^{+}}{{\mathit e}^{-}}$, $4.600 - 4.699$ GeV
$-0.86$ $\pm0.03$ $\pm0.02$ 3201 2
HINSON
2005
CLEO ${{\mathit e}^{+}}{{\mathit e}^{-}}$ $\approx{}{{\mathit \Upsilon}{(4S)}}$
$-0.91$ $\pm0.42$ $\pm0.25$ 3
ALBRECHT
1994B
 ARG ${{\mathit e}^{+}}{{\mathit e}^{-}}$ $\approx{}$10 GeV
• • We do not use the following data for averages, fits, limits, etc. • •
$-0.82$ ${}^{+0.09}_{-0.06}$ ${}^{+0.06}_{-0.03}$ 700 4
CRAWFORD
1995
CLE2 See HINSON 2005
$-0.89$ ${}^{+0.17}_{-0.11}$ ${}^{+0.09}_{-0.05}$ 350 5
BERGFELD
1994
CLE2 See CRAWFORD 1995
1  ABLIKIM 2023AT measures ${{\mathit \alpha}}$ of ${{\mathit \Lambda}_{{{c}}}^{+}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \mu}^{+}}{{\mathit \nu}_{{{\mu}}}}$ decay over eight ${{\mathit q}^{2}}$ bins from zero to the kinematic endpoint. The value provided here is $\langle {{\mathit \alpha}}\rangle $, averaged over ${{\mathit q}^{2}}$. The analysis uses form factors extracted from a simultaneous fit to electron and muon mode data.
2  HINSON 2005 measures the form-factor ratio $\mathit R{}\equiv\mathit f_{2}/\mathit f_{1}$ for ${{\mathit \Lambda}_{{{c}}}^{+}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit e}^{+}}{{\mathit \nu}_{{{e}}}}$ events to be $-0.31$ $\pm0.05$ $\pm0.04$ and the pole mass to be $2.21$ $\pm0.08$ $\pm0.14$ GeV/c${}^{2}$, and from these calculates $\alpha $, averaged over $\mathit q{}^{2}$, where $\langle \mathit q{}^{2}\rangle ~=~0.67~$(GeV/c)${}^{2}$.
3  ALBRECHT 1994B uses ${{\mathit \Lambda}}{{\mathit e}^{+}}$ and ${{\mathit \Lambda}}{{\mathit \mu}^{+}}$ events in the mass range $1.85<\mathit M({{\mathit \Lambda}}{{\mathit \ell}^{+}})<2.20$ GeV.
4  CRAWFORD 1995 measures the form-factor ratio $\mathit R{}\equiv\mathit f_{2}/\mathit f_{1}$ for ${{\mathit \Lambda}_{{{c}}}^{+}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit e}^{+}}{{\mathit \nu}_{{{e}}}}$ events to be $-0.25$ $\pm0.14$ $\pm0.08$ and from this calculates $\alpha $, averaged over $\mathit q{}^{2}$, to be the above.
5  BERGFELD 1994 uses ${{\mathit \Lambda}}{{\mathit e}^{+}}$ events.
References