Strong decays of charmed baryons in heavy hadron chiral perturbation theory

Strong decays of charmed baryons are analyzed in the framework of heavy hadron chiral perturbation theory (HHChPT) in which heavy quark symmetry and chiral symmetry are synthesized. HHChPT works excellently for describing the strong decays of s-wave charmed baryons. For $L=1$ orbitally excited states, two of the unknown couplings, namely, h₂ and h₁₀, are determined from the resonant Λc⁺ππ mode produced in the Λc(2593) decay and the width of Σc(2800), respectively. Predictions for the strong decays of the p-wave charmed baryon states Λc(2625), Ξc(2790) and Ξc(2815) are presented. Since the decay Λc(2593)⁺→Λc⁺ππ receives nonresonant contributions, our value for h₂ is smaller than the previous estimates. We also discuss the first positive-parity excited charmed baryons. We conjecture that the charmed baryon Λc(2880) with JP=5/20+ is an admixture of Λc2(5/20+) with an Λc3^''(5/20+); both are $L=2$ orbitally excited states. The potential model suggests JP=5/20- or 3/20+ for Λc(2940)⁺. Measurements of the ratio of Σc*π/Σcπ will enable us to discriminate the JP assignments for Λc(2940). We advocate that the JP quantum numbers of Ξc(2980) and Ξc(3077) are 1/20+ and 5/20+, respectively. Under this JP assignment, it is easy to understand why Ξc(2980) is broader than Ξc(3077).