Sensitivity of jet substructure to jet-induced medium response

Understand

Jet quenching in heavy ion collisions is expected to be accompanied by recoil effects, but unambiguous signals for the induced medium response have been difficult to identify so far.

• Here, we argue that modern jet substructure measurements can improve this situation qualitatively since they are sensitive to the momentum distribution inside the jet.
• We show that the groomed subjet shared momentum fraction $z_g$, and the girth of leading and subleading subjets signal recoil effects with dependencies that are absent in a recoilless baseline.
• We find that recoil effects can explain most of the medium modifications to the $z_g$ distribution observed in data.