Recent progress on HQET lagrangian

Abstract

HQET lagrangian up to $1/m^3$ terms is discussed. Consequences of reparameterization invariance are considered. Results for the chromomagnetic interaction coefficient at two loops, and in all orders in the large--${\beta }_1$ approximation, are presented.

Comments: LaTeX2e, 13 pages, figures included; Invited plenary talk at the IV Int. Workshop on Progress in Heavy Quark Physics, Rostock, September 20-22