A Lattice Calculation of the Isgur-Wise Function

Abstract

We calculate the Isgur-Wise function ($ξ_0$) by measuring the heavy-heavy meson transition matrix element on the lattice in the quenched approximation. The standard Wilson action is used for both the heavy and the light quarks. Our numerical results are compared with various model calculations and experimental data. In particular, using a linear fit, we find $ρ^2 = 1.24\pm .26 \pm .26 $. (The slope of $ξ_0$ at the zero-recoil point is $-ρ^2$.) Using instead the parametrization of $ξ_0$ suggested by Neubert and Rieckert and fitting the lattice data up to $v\cdot v' \sim 1.2$, we find $ρ^2_{NR}=1.41\pm.19\pm.19$