Speaker
Dr
Konrad Tywoniuk
(Universitat de Barcelona)
Description
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 a background color field, e.g. such as expected in a quark-gluon plasma, one also has to consider a hard scale arising from the medium interactions. It was recently shown that due to the collinear nature of QCD splittings, high-energy jets are typically quite collimated and are not resolved by the medium, i.e. they are only seen as a total charge and lose energy coherently. Assuming this scenario holds for all jets, 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. Medium-induced radiation is accounted for using the established factorization of multiple branchings leading to the probabilistic rate equation - which we presently improve upon by introducing finite-size effects and a proper regularization prescription in the infrared. This mechanism is particularly important for the transport of energy away from the jet axis up to large angles. For the intra-jet structure, on the other hand, we find the striking importance of so-called "antiangular ordered radiation," resulting from the slight decoherence of the jet during the passage through the medium.
Keywords
jet physics, jet quenching
Primary author
Dr
Konrad Tywoniuk
(Universitat de Barcelona)
Co-author
Dr
Yacine Mehtar-Tani
(IPTH, CEA Saclay)
