HEAVY-LIGHT HADRONS AND CURRENT-INDUCED TRANSITIONS AMONG THEM

We discuss several dynamical schemes that allow one to calculate current induced transitions among heavy-light hadrons. Among these are a Bethe-Salpeter wavefunction calculation, a Bloch-Nordsiek approximation and a QCD Green function approach. In the limit where the mass of the heavy quark (or hadron) becomes large but its four velocity νμ = pμ/M remains fixed all these schemes lead to the same results. Namely they give a product of a trace over U(12) wavefunctions with the current sandwiched in between and a (to be determined) form factor function which is normalised to unity at maximum momentum transfer. The various approaches sketched here are useful in that they allow one to identify and calculate 1/M corrections to the heavy mass limit. © 1990.