Visualizing How Jet Structure Shapes Jet Wakes

The ATLAS Collaboration has developed a method to analyze largeradius jets composed of skinny R = 0.2 subjets in heavy-ion collisions. We first demonstrate that the measurements pioneered by ATLAS constrain the value of Lres, the resolution length of QGP—and rule out any picture in which an entire parton shower loses energy coherently as a single entity. We then analyze the response of the medium to the passage of large-radius R = 2 jets containing two skinny subjets in gamma-jet events. We introduce novel jet-shape observables that allow us to visualize how the internal structure of large-radius jets shapes the wakes they excite in the QGP. We find that even when the subjets are ∼ 0.8 radians apart, the angular shape of the soft hadrons originating from their wake forms a single broad structure. Only when the two subjets are even farther apart are two sub-wakes revealed. We show that the way in which jet structure shapes the structure of jet-induced wakes can be visualized with similar clarity in experiments by using only low-pT hadrons. The observables we introduce offer a new and distinctive way of seeing jet-induced wakes – and wake substructure – in heavy-ion collision data.