TWO LECTURES ON HEAVY QUARK EFFECTIVE THEORY AND SPECTROSCOPY OF HEAVY-LIGHT MESONS

I give a basic introduction to the Heavy Quark Effective Theory. I discuss the implications of the heavy quark limit for hadron spectroscopy, devoting particular attention to the classification of heavy-light mesons in doublets. I show how using an approach based on effective lagrangian terms displaying new symmetries that arise in such a limit, it is possible to make predictions for strong decays of heavy-light mesons with the emission of a light meson that are helpful in identifying recently discovered states. Moreover, I consider how weak transitions among members of the various doublets can be expressed in terms of universal form factors. As a last topic, I discuss the case of heavy mesons with hidden flavour, with particular reference to the state X(3872).