Oak Ridge National Laboratory

Physics Division

Physics Division Seminars

Physics Division Seminars bring us speakers on a variety of physics related subjects. Usually these are held in the Building 6008 large Conference Room, at 3:00 pm on the chosen day, but times and locations may vary. For more information, contact our seminar chairman,

Alfredo Galindo-Uribarri
Tel (Office): (865) 574-6124  (FAX): (865) 574-1268


Tue., January 31, 2017, at 3:00 PM - 4:00 PM (refreshments served at 2:40 PM)

Hard Probes of the Hot Medium

Redmer Alexander Bertens, University of Tennessee, Knoxville
Bldg. 6008 Large Conference Room

The Pb--Pb physics program of the LHC at CERN is aimed at studying the quark-gluon plasma (QGP), a state of deconfined quarks and gluons that is formed in heavy-ion collisions. Jets, collimated bunches of particles originating from the fragmentation of a hard-scattered parton emitted in the early stages of a collision, can be used as a tomographic tool to study the QGP. As the hard scattered parton traverses the plasma, it loses energy (`jet quenching') via elastic and radiative interactions with medium constituents. Therefore, modifications of jet properties observed in heavy-ion collisions can be used to deduce properties of the QGP.

This talk will give a brief introduction to `hard probes', covering measurements of high-pt single particles and jets, and shows how a systematic comparison of models to experimental results can be used to extract transport parameters of the QGP. Parton energy loss mechanisms are explored via measurements of recoil jet yields and the event-plane dependence of jet production. Modifications of the parton shower itself are studied using jet shape observables, to more directly quantify medium effects on fragmentation. Special attention will be given to the experimental challenges posed by reconstructing jets in the presence of the large and strongly fluctuating background that is present in heavy-ion collisions.

Alfredo Galindo-Uribarri, (865) 574-6124