Remarks on the Strong Coupling Constants in Heavy Hadron Chiral Lagrangians

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 Ξ ′∗0 c → Ξ0cγ, which is prohibited at tree level by SU(3) symmetry but induced by chiral loops. A measurement of Γ(Ξ ′∗0 c → Ξ0cγ) 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 .