  In the lattice formulation of the Heavy Quark Effective Theory (LHQET), the
classical velocity is renormalized. The origin of this renormalization is the
reduction of Lorentz (or O(4)) invariance to (hyper)cubic invariance. The
renormalization is finite and depends on the form of the decretization of the
reduced heavy quark Dirac equation. For the Forward Time - Centered Space
discretization, the renormalization is computed both perturbatively, to one
loop, and non-perturbatively using an ensemble of lattices provided by the
Fermilab lattice collaboration. The estimates of the leading (linear) shift
agree, and indicate that for small classical velocities, the renormalized
velocity is reduced by about 25-30% relative to its bare (input) value.

High Energy Physics - Lattice