Remarks on the Strong Coupling Constants in Heavy Hadron Chiral Lagrangians

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In the heavy quark limit, there are three independent strong axial coupling constants in chiral Lagrangians for ground-state heavy hadrons: g in the meson sector, and g₁, g₂ in the baryon sector. The coupling g₂ is extracted from recent CLEO measurements of Σc*→Λcπ to be |g₂|=0.57± 0.10, in agreement with the nonrelativistic quark model expectation but in 2σ deviation from the large-Nc argument. The parameter g₁ cannot be determined directly from strong decays of heavy baryons. Nevertheless, some information of g₁ can be learned from the radiative decay Ξc'*⁰→Ξc⁰γ, which is prohibited at tree level by SU(3) symmetry but induced by chiral loops. A measurement of Γ(Ξc'*⁰→Ξc⁰γ) will yield two possible solutions for g₁. Assuming the validity of the quark model relations among different coupling constants, the experimental value of g₂ implies that |g|=0.70± 0.12 and |g₁|=0.93± 0.16.