Abstract

The extraction of the physical properties of hadrons from lattice Quantum Chromodynamics (QCD) calculations is an important and urgent area of research. It is difficult to make calculations of hadronic properties because QCD is a highly non-linear field theory. Lattice gauge theory is the only known ab initio way of making nonperturbative calculations of QCD. The lattice has been highly successful but the computational cost of simulating light quark masses means that hadronic calculations at physical quark masses are some way off.

We present a method of extrapolating from the heavy quark regime, where lattice calculations now occur, to physical quark masses, which carefully incorporates key, model independent constraints --- especially those imposed by chiral symmetry. This extrapolation method not only allows one to extract physical hadron masses with high accuracy, but also allows the extraction of other properties, including the pion--nucleon sigma term and the J parameter for the vector mesons.