SIMPLY MODELING MESON HEAVY-QUARK EFFECTIVE THEORY

A simple relativistic model of heavy-quark-light-quark mesons is propo sed. In an expansion in inverse powers of the heavy-quark mass we find that all zeroth- and first-order heavy-quark symmetry relations are s atisfied. The main results are the following. The difference between t he meson mass and the heavy-quark mass plays a significant role even a t zeroth order. The slope of the Isgur-Wise function at the zero recoi l point is typically less than -1. The first-order correction to the p seudoscalar decay constant is large and negative. The four universal f unctions describing the first-order corrections to the semileptonic de cay form factors are small. These latter corrections are quite insensi tive to the choice of model parameters, and in particular to the effec ts of hyperfine mass splitting.