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CHARMED BARYONS
($\mathit C$ = $+1$)
${{\mathit \Lambda}_{{{c}}}^{+}}$ = ${{\mathit u}}{{\mathit d}}{{\mathit c}}$, ${{\mathit \Sigma}_{{{c}}}^{++}}$ = ${{\mathit u}}{{\mathit u}}{{\mathit c}}$, ${{\mathit \Sigma}_{{{c}}}^{+}}$ = ${{\mathit u}}{{\mathit d}}{{\mathit c}}$, ${{\mathit \Sigma}_{{{c}}}^{0}}$ = ${{\mathit d}}{{\mathit d}}{{\mathit c}}$,
${{\mathit \Xi}_{{{c}}}^{+}}$ = ${{\mathit u}}{{\mathit s}}{{\mathit c}}$, ${{\mathit \Xi}_{{{c}}}^{0}}$ = ${{\mathit d}}{{\mathit s}}{{\mathit c}}$, ${{\mathit \Omega}_{{{c}}}^{0}}$ = ${{\mathit s}}{{\mathit s}}{{\mathit c}}$

INSPIRE JSON PDGID:

${{\mathit \Lambda}_{{{c}}}{(2595)}^{+}}$

$I(J^P)$ = $0(1/2^{-})$

The ${{\mathit \Lambda}_{{{c}}}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ mode is largely, and perhaps entirely, ${{\mathit \Sigma}_{{{c}}}}{{\mathit \pi}}$, which is just at threshold; since the ${{\mathit \Sigma}_{{{c}}}}$ has $\mathit J{}^{P} = 1/2{}^{+}$, the $\mathit J{}^{P}$ here is almost certainly ${}^{}1/2{}^{-}$. This result is in accord with the theoretical expectation that this is the charm counterpart of the strange ${{\mathit \Lambda}{(1405)}}$.

${{\mathit \Lambda}_{{{c}}}{(2595)}^{+}}$ MASS

$2592.25$ $\pm0.28$ MeV

${{\mathit \Lambda}_{{{c}}}{(2595)}^{+}}-{{\mathit \Lambda}_{{{c}}}^{+}}$ MASS DIFFERENCE

$305.79$ $\pm0.24$ MeV

${{\mathit \Lambda}_{{{c}}}{(2595)}^{+}}$ WIDTH

$2.6$ $\pm0.6$ MeV

${{\mathit \Lambda}_{{{c}}}{(2595)}^{+}}$ DECAY MODES

${{\mathit \Lambda}_{{{c}}}^{+}}{{\mathit \pi}}{{\mathit \pi}}$ and its submode ${{\mathit \Sigma}_{{{c}}}{(2455)}}{{\mathit \pi}}$ $-$ the latter just barely $-$ are the only strong decays allowed for an excited ${{\mathit \Lambda}_{{{c}}}^{+}}$ having this mass; and the submode seems to dominate.

Mode

Fraction ($\Gamma_i$ / $\Gamma$)

Scale Factor/
Conf. Level

P(MeV/c)

${{\mathit \Lambda}_{{{c}}}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$

($40$ $\pm14$ ) $\%$

${{\mathit \Sigma}_{{{c}}}{(2455)}^{++}}{{\mathit \pi}^{-}}$

($15$ $\pm6$ ) $\%$

${{\mathit \Sigma}_{{{c}}}{(2455)}^{0}}{{\mathit \pi}^{+}}$

($15$ $\pm6$ ) $\%$

${{\mathit \Lambda}_{{{c}}}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ 3-body

${{\mathit \Lambda}_{{{c}}}^{+}}{{\mathit \pi}^{0}}{{\mathit \pi}^{0}}$

($60$ $\pm14$ ) $\%$

${{\mathit \Lambda}_{{{c}}}^{+}}{{\mathit \pi}^{0}}$

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

[1]

See AALTONEN 2011H, Fig. 8, for the calculated ratio of ${{\mathit \Lambda}_{{{c}}}^{+}}{{\mathit \pi}^{0}}{{\mathit \pi}^{0}}$ and ${{\mathit \Lambda}_{{{c}}}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ partial widths as a function of the ${{\mathit \Lambda}_{{{c}}}{(2595)}^{+}}$ $−$ ${{\mathit \Lambda}_{{{c}}}^{+}}$ mass difference. At our value of the mass difference, the predicted ratio is about$~$4. Using the measured value of ${{\mathit \Lambda}_{{{c}}}^{+}}{{\mathit \pi}^{0}}{{\mathit \pi}^{0}}$ branching fraction and assuming the ${{\mathit \Lambda}_{{{c}}}}{{\mathit \pi}}{{\mathit \pi}}$ branching fractions sum to unity, we derive the ${{\mathit \Lambda}_{{{c}}}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ branching fraction. The derived ratio of the ${{\mathit \Lambda}_{{{c}}}}{{\mathit \pi}^{0}}{{\mathit \pi}^{0}}$ to ${{\mathit \Lambda}_{{{c}}}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ partial widths is correspondingly $1.5$ $\pm0.2$.

[2]

A test that the isospin is indeed 0, so that the particle is indeed a ${{\mathit \Lambda}_{{{c}}}^{+}}$.

Constrained Fit information

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