${{\mathit \Lambda}_{{{c}}}^{+}}$ MASS

INSPIRE   PDGID:
S033M
Our value in 2004, $2284.9$ $\pm0.6$ MeV, was the average of the measurements now filed below as “not used.” The BABAR measurement is so much better that we use it alone. Note that it is about 2.6 (old) standard deviations above the 2004 value.

The fit also includes ${{\mathit \Sigma}_{{{c}}}}-{{\mathit \Lambda}_{{{c}}}^{+}}$ and ${{\mathit \Lambda}_{{{c}}}^{*+}}-{{\mathit \Lambda}_{{{c}}}^{+}}$ mass-difference measurements, but this doesn't affect the ${{\mathit \Lambda}_{{{c}}}^{+}}$ mass. The new (in 2006) ${{\mathit \Lambda}_{{{c}}}^{+}}$ mass simply pushes all those other masses higher.
VALUE (MeV) EVTS DOCUMENT ID TECN  COMMENT
$\bf{ 2286.46 \pm0.14}$ OUR FIT
$2286.46$ $\pm0.14$ 4891 1
AUBERT,B
2005S
BABR ${{\mathit \Lambda}}{{\mathit K}_S^0}$ ${{\mathit K}^{+}}$ and ${{\mathit \Sigma}^{0}}{{\mathit K}_S^0}$ ${{\mathit K}^{+}}$
• • We do not use the following data for averages, fits, limits, etc. • •
$2284.7$ $\pm0.6$ $\pm0.7$ 1134
AVERY
1991
CLEO Six modes
$2281.7$ $\pm2.7$ $\pm2.6$ 29
ALVAREZ
1990B
NA14 ${{\mathit p}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}$
$2285.8$ $\pm0.6$ $\pm1.2$ 101
BARLAG
1989
NA32 ${{\mathit p}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}$
$2284.7$ $\pm2.3$ $\pm0.5$ 5
AGUILAR-BENIT..
1988B
LEBC ${{\mathit p}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}$
$2283.1$ $\pm1.7$ $\pm2.0$ 628
ALBRECHT
1988C
ARG ${{\mathit p}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}$, ${{\mathit p}}{{\overline{\mathit K}}^{0}}$, ${{\mathit \Lambda}}$3 ${{\mathit \pi}}$
$2286.2$ $\pm1.7$ $\pm0.7$ 97
ANJOS
1988B
E691 ${{\mathit p}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}$
$2281$ $\pm3$ 2
JONES
1987
HBC ${{\mathit p}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}$
$2283$ $\pm3$ 3
BOSETTI
1982
HBC ${{\mathit p}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}$
$2290$ $\pm3$ 1
CALICCHIO
1980
HYBR ${{\mathit p}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}$
1  AUBERT,B 2005S uses low-Q ${{\mathit \Lambda}}{{\mathit K}_S^0}$ ${{\mathit K}^{+}}$ and ${{\mathit \Sigma}^{0}}{{\mathit K}_S^0}$ ${{\mathit K}^{+}}$ decays to minimize systematic errors. The error above includes systematic as well as statistical errors. Many cross checks and adjustments to properties of the BABAR detector, as well as the large number of clean events, make this by far the best measurement of the ${{\mathit \Lambda}_{{{c}}}^{+}}$ mass.
References