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Strong Decays of Charmed Baryons in Heavy Hadron Chiral Perturbation Theory: An Update

We first give a brief overview of the charmed baryon spectroscopy and discuss their possible structure and spin-parity assignments in the quark model. With the new Belle measurement of the widths of $Σ_c(2455)$ and $Σ_c(2520)$ and the recent CDF measurement of the strong decays of $Λ_c(2595)$ and $Λ_c(2625)$, we give updated coupling constants in heavy hadron chiral perturbation theory. We find $g_2=0.565^{+0.011}_{-0.024}$ for $P$-wave transitions between $s$-wave and $s$-wave baryons, and $h_2$, one of the couplings responsible for $S$-wave transitions between $s$-wave and $p$-wave baryons, is extracted from $Λ_c(2595)^+\toΛ_c^+ππ$ to be $0.63\pm0.07$. It is substantially enhanced compared to the old value of order 0.437. With the help from the quark model, two of the couplings $h_{10}$ and $h_{11}$ responsible for $D$-wave transitions between $s$-wave and $p$-wave baryons are determined from $Σ_c(2880)$ decays. There is a tension for the coupling $h_2$ as its value extracted from $Λ_c(2595)^+\to Λ_c^+ππ$ will imply $Ξ_c(2790)^0\toΞ'_cπ$ and $Ξ_c(2815)^+\toΞ_c^*π$ rates slightly above the current limits. It is conceivable that SU(3) flavor symmetry breaking can help account for the discrepancy.