Nuclear modification factors for jet fragmentation

Understand

Using a recently-developed perturbative-QCD approach for jet evolution in a dense quark-gluon plasma, we study the nuclear modification factor for the jet fragmentation function.

• The qualitative behaviour that we find is in agreement with the respective experimental observations in Pb+Pb collisions at the LHC: a pronounced nuclear enhancement at both ends of the spectrum.
• Our Monte Carlo simulations are supplemented with analytic estimates which clarify the physical interpretation of the results.
• The main source of theoretical uncertainty is the sensitivity of our calculations to a low-momentum cutoff which mimics confinement.