Computation of $\bar{\Lambda}$ and $\lambda_1$ with Lattice QCD

Abstract

We pursue a new method, based on lattice QCD, for determining the quantities $\bar{\Lambda}$, $\lambda_1$, and $\lambda_2$ of heavy-quark effective theory. We combine Monte Carlo data for the meson mass spectrum with perturbative calculations of the short-distance behavior, to extract $\bar{\Lambda}$ and $\lambda_1$ from a formula from HQET. Taking into account uncertainties from fitting the mass dependence and from taking the continuum limit, we find $\bar{\Lambda} = 0.68{+0.02}_{-0.12} \text{GeV}$ and $\lambda_1 = -(0.45 \pm 0.12) \text{GeV}^2$ in the quenched approximation.