Renormalization of the effective theory for heavy quarks at small velocity Original Research Article

The slope of the Isgur-Wise function at the normalization point, ξ(1) (1), is one of the basic parameters for the extraction of the CKM matrix element Vcb from exclusive semileptonic decay data. A method for measuring this parameter on the lattice is the effective theory for heavy quarks at small velocity v. This theory is a variant of the heavy quark effective theory in which the motion of the quark is treated as a perturbation. In this work we study the lattice renormalization of the slow heavy quark effective theory. We show that the renormalization of ξ(1) (1) is not affected by ultraviolet power divergences, implying no need of difficult non-perturbative subtractions. A lattice computation of ξ(1) (1) with this method is therefore feasible in principle. The one-loop renormalization constants of the effective theory for slow heavy quarks are computed to order v2 together with the lattice-continuum renormalization constant of ξ(1) (1).