QCD and hadron structure

Abstract

There is considerable interest in the possibility of extracting model independent information on the masses and other properties of hadrons from lattice QCD, even though the state of the art involves light quark masses considerably higher than those found in nature. We review the applicability of effective field theory to this problem. Taking the rho meson as an example, we show that conventional, dimensionally regularized field theory is not sufficiently convergent to provide a reliable method of extrapolation. The reason for the poor convergence is discussed, along with the solution which this suggests. Finally we outline a very interesting suggestion of a connection between hadron masses in full and quenched QCD, using the nucleon and delta as examples.