An event generator is constructed on the basis of a model of multiple
scattering of partons so that the trajectory of a parton traversing a dense and
expanding medium can be tracked. The parameters in the code are adjusted to fit
the \Delta\phi azimuthal distribution on the far side when the trigger momentum
is in the non-perturbative region, p_T(trigger)<4 GeV/c. The dip-bump structure
for 1<p_T(assoc)<2.5 GeV/c is reproduced by averaging over the exit tracks of
deflected jets. An essential characteristic of the model, called Markovian
Parton Scattering (MPS) model, is that the scattering angle is randomly
selected in the forward cone at every step of a trajectory that is divided into
many discrete steps in a semi-classical approximation of the non-perturbative
scattering process. Energy loss to the medium is converted to thermal partons
which hadronize by recombination to give rise to the pedestal under the bumps.
When extended to high trigger momentum with \pt(trigger) >8 GeV/c, the model
reproduces the single-peak structure observed by STAR without invoking any new
dynamical mechanism.Comment: 20 pages + 3 figure