  We use thermalization indicators and numerical linked cluster expansions to
probe the onset of many-body localization in a disordered one-dimensional
hard-core boson model in the thermodynamic limit. We show that after
equilibration following a quench from a delocalized state, the momentum
distribution indicates a freezing of one-particle correlations at higher values
than in thermal equilibrium. The position of the delocalization to localization
transition, identified by the breakdown of thermalization with increasing
disorder strength, is found to be consistent with the value from the level
statistics obtained via full exact diagonalization of finite chains. Our
results strongly support the existence of a many-body localized phase in the
thermodynamic limit.
