Lattice HQET calculation of the Isgur-Wise function

We calculate the Isgur-Wise function on the lattice, simulating the light quark with the Wilson action and the heavy quark with a direct lattice implementation of the heavy-quark effective theory. Improved smearing functions produced by a variational technique, MOST, are used to reduce thestatistical errors and to minimize excited-state contamination of the ground-state signal. Calculating the required matching factors, we obtain ξ'(1)=-0.64(13) for the slope of the Isgur-Wise function in continuum-HQET in the MS scheme at a scale of 4.0 GeV. (orig.)