  While experimental observations, such as the mass hierarchy effect, are
attributed and analyzed within radiative models, their interpretation crucially
depends on collisional energy loss contribution, which is often neglected in
such analyses. To our knowledge, neither a (direct) simple relation between
collisional energy loss and heavy quark mass is established, nor an observable
that quantifies this effect. On the other hand, the upcoming high-luminosity
measurements at RHIC and LHC will generate heavy flavor data with unprecedented
precision, providing an opportunity to utilize high-pT heavy flavor data to
analyze the interaction mechanisms in the quark-gluon plasma. To this end, we
employ a recently developed DREENA framework based on our dynamical energy loss
formalism to study the mass hierarchy in heavy flavor suppression. We present
i) Analytical derivation of a direct relation between collisional
suppression/energy loss and heavy quark mass. ii) A novel observable sensitive
only to the collisional energy loss mechanism to be tested by future
high-precision experiments. iii) Analytical and numerical extraction of the
mass hierarchy in collisional energy losses through this observable.
