Jul 5 – 12, 2017
Venice, Italy
Europe/Zurich timezone
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Jet evolution in a dense medium: event-by-event fluctuations and multi-particle correlations

Jul 7, 2017, 3:30 PM
Room Mangano (Palazzo del Casinò)

Room Mangano

Palazzo del Casinò

Parallel Talk Heavy Ion Physics Heavy ion physics


Dr Miguel Ángel Escobedo Espinosa (University of Jyväskylä)


We study the gluon distribution produced via successive medium-induced branchings
by an energetic jet propagating through a weakly-coupled quark-gluon plasma. We show that
under suitable approximations, the jet evolution is a Markovian stochastic process,
which is exactly solvable. For this process, we construct exact analytic solutions
for all the n-point correlation functions describing the gluon distribution
in the space of energy [1,2]. Using these results, we study the event-by-event distribution of the energy lost by the jet at large angles and of the multiplicities
of the soft particles which carry this energy. We find that the event-by-event fluctuations are huge: the standard deviation in the energy loss is parametrically as large as its mean value [1]. This has important consequences for the phenomenology
of di-jet asymmetry in Pb+Pb collisions at the LHC: it implies that the fluctuations in the branching process can contribute to the measured asymmetry on an equal footing with the geometry of the di-jet event (i.e. as the difference between the in-medium path lengths of the two jets). We compute the higher moments of the multiplicity distribution and identify a remarkable regularity known as Koba-Nielsen-Olesen (KNO) scaling [2].

These predictions could be tested via event-by-event measurements of the di-jet asymmetry.

[1] Event-by-event fluctuations in the medium-induced jet evolution
M. Escobedo, E. Iancu, e-Print: arXiv:1601.03629 [hep-ph], JHEP 1605 (2016) 008.

[2] Multi-particle correlations and KNO scaling in the medium-induced jet evolution
M. Escobedo, E. Iancu, e-Print: arXiv:1609.06104 [hep-ph], JHEP 1612 (2016) 104.

Primary authors

Dr Miguel Ángel Escobedo Espinosa (University of Jyväskylä) Prof. Edmond Iancu (Institut de Physique Théorique)

Presentation materials