Recently, Stech found form factor relations for heavy to light transitions based on two simple dynamical assumptions for a spectator particle. In this paper we generalize his approach to the case of baryons and find that for ${\mathrm{\Lambda }}_{\mathit{Q}}$→Λ (Q=b or c) only one independent form factor remains in the limit ${\mathit{m}}_{\mathit{Q}}$→∞. Furthermore, combining with the model of Guo and Kroll we determine both of the two form factors for ${\mathrm{\Lambda }}_{\mathit{Q}}$→Λ in the heavy quark limit. The results are applied to ${\mathrm{\Lambda }}_{\mathit{b}}$→Λ+J/ψ which is not clarified both theoretically and experimentally. It is found that the branching ratio of ${\mathrm{\Lambda }}_{\mathit{b}}$→Λ+J/ψ is of order ${10}^{\mathrm{-}5}$. © 1996 The American Physical Society.

• Received 19 October 1995

DOI:https://doi.org/10.1103/PhysRevD.53.4946