The Charm Quark on the Lattice

We formulate lattice fermions in a way that encompasses Wilson fermions as well as the static and non-relativistic approximations. In particular, we treat $m_qa$ systematically ($m_q$ is the fermion mass) showing how to understand the Wilson action as an effective action for systems with $\vek{p}\ll m_q$. The results show how to extract matrix elements and the spectrum from simulations with $m_qa\approx1$, which is relevant for the charm quark.