  We investigate the clustering of dark matter halos in Lagrangian space in
terms of their two-point correlation function, spanning more than 4 orders of
magnitudes of halo masses. Analyzing a set of collisionless scale-free
128^3-particle N-body simulations with spectral indices n = -2,-1, we measure
the first two Lagrangian bias parameters b_1 and b_2 relating halo and mass
correlations. We find that the Mo & White leading-order formula for b_1
describes the clustering of halos with mass M ~ M_* quite accurately, where M_*
indicates the characteristic non-linear mass. Smaller halos turn out to be less
clustered in Lagrangian space than predicted by Mo & White. Our findings are
consistent with the recent results of Jing for the clustering of halo
populations in Eulerian space, demonstrating that the discrepancies between the
N-body and analytical Mo & White prediction for the bias exist already in
Lagrangian space. This shows that a more refined theoretical algorithm for
selecting halos in the initial conditions needs to be developed. Finally, we
present a very accurate fitting formula for the linear halo bias factor b_1 in
Lagrangian space.
