Cabibbo-allowed nonleptonic weak decays of charmed baryons

Cabibbo-allowed nonleptonic weak decays of charmed baryons ${\mathrm{\Lambda }}_{\mathit{c}}^{+}$, ${\mathrm{\Xi }}_{\mathit{c}}^{0\mathit{A}}$, ${\mathrm{\Xi }}_{\mathit{c}}^{+\mathit{A}}$, and ${\mathrm{\Omega }}_{\mathit{c}}^0$ into an octet baryon and a pseudoscalar meson are analyzed. The nonfactorizable contributions are evaluated under the pole approximation, and it turns out that the s-wave amplitudes are dominated by the low-lying 1/$2^{\mathrm{-}}$ resonances, while p-wave ones are governed by the ground state 1/$2^{+}$ poles. The MIT bag model is employed to calculate the coupling constants, form factors, and baryon matrix elements. Our conclusions are the following: (i) s waves are no longer dominated by commutator terms; the current-algebra method is not applicable to parity-violating amplitudes. (ii) Nonfactorizable W-exchange effects are generally important; they can be comparable to and sometimes even dominate over factorizable contributions, depending on the decay modes under consideration. (iii) The large-${\mathit{N}}_{\mathit{c}}$ approximation for factorizable amplitudes also works in the heavy baryon sector and it accounts for the color nonsuppression of ${\mathrm{\Lambda }}_{\mathit{c}}^{+}$→pK${\mathrm{¯}}^0$ relative to ${\mathrm{\Lambda }}_{\mathit{c}}^{+}$→Λ${\mathrm{\pi }}^{+}$. (iv) A measurement of the decay rate and the sign of the α asymmetry parameter of certain proposed decay modes will help discern various models. (v) p waves are the dominant contributions to the decays ${\mathrm{\Lambda }}_{\mathit{c}}^{+}$→${\mathrm{\Xi }}^0$ ${\mathit{K}}^{+}$ and ${\mathrm{\Xi }}_{\mathit{c}}^{0\mathit{A}}$→${\mathrm{\Sigma }}^{+}$ ${\mathit{K}}^{\mathrm{-}}$, but they are subject to a large cancellation; this renders present theoretical predictions on these two channels unreliable.