Perturbative heavy quark-antiquark systems

Abstract

Abstract: In this review I cover recent developments concerning the construction of non-relativistic effective theories for perturbative heavy quark-antiquark systems and heavy quark mass definitions. I then discuss next-to-next-to-leading order results on quarkonium masses and decay, top quark pair production near threshold and QCD sum rules for Υ mesons. (November 1999, CERN-TH/99-355, hep-ph/9911490) Heavy quark effective field theory has profoundly influenced the way we think about mesons made of a heavy and a light quark [1]. It provides a systematic expansion in powers of αs and ΛQCD/mQ. Perhaps more important, it separates hard (momenta l ∼ mQ) and soft (l ∼ ΛQCD) physics. Hard effects can be calculated; spin-flavour symmetry [2] relates soft effects and makes the framework predictive. The construction of an effective theory for