  MMedium excitation by jet shower propagation inside a quark-gluon plasma is
studied within a linear Boltzmann transport and a multiphase transport model.
Contrary to the naive expectation, it is the deflection of both the jet shower
and the Mach-cone-like excitation in an expanding medium that is found to gives
rise to a double-peak azimuthal particle distribution with respect to the
initial jet direction. Such deflection is the strongest for hadron-triggered
jets which are often produced close to the surface of dense medium due to
trigger-bias and travel against or tangential to the radial flow. Without such
trigger bias, the effect of deflection on $\gamma$-jet showers and their medium
excitation is weaker. Comparative study of hadron and $\gamma$-triggered
particle correlations can therefore reveal the dynamics of jet-induced medium
excitation in high-energy heavy-ion collisions.
