Feb 5 – 11, 2017
Hyatt Regency Chicago
America/Chicago timezone

Exploring jet sub-structure with jet shapes in ALICE

Feb 7, 2017, 3:40 PM
Regency D

Regency D


Davide Caffarri (CERN)


The heavy-ion physics program at the LHC aims at characterizing the high energy density, high temperature, deconfined partonic state of matter called Quark-Gluon Plasma (QGP). High-momentum partons, that then hadronize in jets, are useful tools to study the QGP properties since they are produced via hard scattering processes and they probe the full evolution of the system, losing energy while passing through it.

In particular the characterization of the jet substructure can bring insight on the microscopic nature of modifications induced on these partons by the medium. These modifications can be studied using a set of jet shape observables like the first order radial moment, the jet momentum dispersion, the difference between the leading and sub-leading jet tracks. Moreover measurements of the jet mass will allow for direct experimental access to the virtuality evolution of partons interacting with the medium.

Measurements of these observables in pp or p-Pb collisions will be presented and compared with theoretical calculations, as well as with Monte Carlo generators, providing important tests of QCD in elementary collisions.

We will present final ALICE results on jet shapes in Pb-Pb collisions at
$\sqrt{s_{\rm NN}}=2.76~\rm{TeV}$, in order to investigate possible modifications of the distribution of particles within the jets. In addition, we present new results on jet mass in Pb-Pb collisions. These measurements have been performed using new techniques for background subtraction and a 2D unfolding procedure to correct the shapes to particle level.

Preferred Track Jets and High pT Hadrons
Collaboration ALICE

Primary author

Presentation materials