We consider momentum broadening and energy loss of high momentum partons in a hot non-Abelian plasma due to collisions. We solve the coupled system of Wong-Yang-Mills equations on a lattice in real time, including binary hard elastic collisions among the partons. The collision kernel is constructed such that the total collisional energy loss and momentum broadening are lattice spacing independent. We find that the transport coefficient $hat{q}$ corresponding to transverse momentum broadening receives sizable contributions from a power-law tail in the $p_perp$-distribution of high-momentum partons. We establish the scaling of $hat{q}$ and of $dE/dx$ with density, temperature and energy in the weak-coupling regime. We also estimate the nuclear modification factor $R_{AA}$ due to elastic energy loss of a jet in a classical Yang-Mills field.
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