Path length dependence and fluctuations of energy loss in heavy-ion collisions

Understanding the process by which jets lose energy in the quark-gluon plasma

(QGP) is

one of the key goals of the experimental programs at RHIC and the LHC.  Jet

energy loss is well established experimentally in both facilities and current

work focuses on the details of how energy loss depends on the details of the

jets, including their flavor and structure, as well as how the energy loss

depends on the path length through the QGP. Understanding both aspects

In this talk, we will discuss the current state of measurements sensitive to

the path length dependence of energy loss in both small and large collision

systems at RHIC and the LHC.  Additionally, we will discuss potential future

observables that could be sensitive to jet-by-jet fluctuations in energy loss.