Understanding jet modifications at the LHC

Jets are collimated QCD multi-particle states that are abundantly produced in heavy-ion collisions at the LHC. Their description in the vacuum is governed by hardest scale of the problem, typically the jet virtuality. In the presence of an interacting background field, e.g. such as expected in a quark–gluon plasma, one also has to consider a hard scale arising from the medium interactions. We show how a factorization of small-angle jet evolution and large-angle medium-induced emissions can be realized and calculate three key observables: the jet RAA, modification of the intra-jet structure and the amount of out-of-cone radiation.