Covariant quark model of form factors in the heavy mass limit

We show that quark models of current matrix-elements based on the Bakamjian-Thomas construction of relativistic states with a fixed number of particles, plus the addivity assumption, are covariant in the heavy-quark limit and satisfies the full set of heavy-quark symmetry relations discovered by Isgur and Wise. We find the lower bound of ϱ2 in such models to be 34 for ground state mesons, independently of any parameter. Another welcome property of these models is that in the infinite momentum limit, the wave functions vanish outside the domain 0 ≤ x ≤1