3,163 research outputs found
Jet quenching
High-pt particles produced in nucleus-nucleus collisions constitute a
powerful tool to study the medium properties. The energy loss resulting from
the propagation of these particles in the produced medium translates into a
suppression of the high-pt yields. These effects are usually associated to
medium-induced gluon radiation which, in turn, predicts a broadening of the
jet-like signals. Both the energy loss and the jet broadening are expected to
increase proportionally to the medium density. In the more realistic case of a
dynamically expanding medium, the gluon radiation becomes anisotropic due to
the presence of a preferred direction in the transverse plane with respect to
the axis of propagation. This anisotropy translates into deformed jet-shapes
which provide new posibilities to study these flows by high-pt measurements.Comment: To appear in the proceedings of the XXXX Rencontres de Moriond. QCD
and high energy hadronic interaction
Theory summary. Hard Probes 2012
I provide a summary of the theoretical talks in Hard Probes 2012 together
with some personal thoughts about the present and the future of the field.Comment: 8 pages. Proceedings of the conference Hard Probes 2012 - Sardinia -
Italy - May 27 -June 1 2012 --- Comments welcom
Hard QCD probes to quark-gluon plasma
Completely unexplored regimes of QCD, dominated by high-density/temperature
effects, are available in heavy ion experiments at collider energies. The
successful RHIC program shows how relevant the high transverse momentum part of
the spectrum is for the characterization of the properties of the created
medium. It points, as well, to interesting properties of the nuclear wave
function at small fraction of momentum x, probably dominated by saturated color
fields. In both domains, the imminent LHC program will provide a phase space
enlarged by orders of magnitude with respect to those studied at RHIC. I will
review the present status of hard probes in heavy ion collisions as well as the
expectations for the LHC.Comment: 8 pages, invited talk at the YKIS Seminar on New Frontiers in QC
Introductory lectures on jet quenching in heavy ion collisions
Jet quenching has become an essential signal for the characterization of the
medium formed in experiments of heavy-ion collisions. After a brief
introduction to the field, we present the full derivation of the medium-induced
gluon radiation spectrum, starting from the diagrammatical origin of the Wilson
lines and the medium averages and including all intermediate steps. The
application of this spectrum to actual phenomenological calculations is then
presented, making comparisons with experimental data and indicating some
improvements of the formalism to the future LHC program. The last part of the
lectures reviews calculations based on the AdS/CFT correspondence on the medium
parameters controlling the jet quenching phenomenon.Comment: 63 pages, 17 figures, Presented at the XLVII Cracow School of
Theoretical Physics, Zakopane, Poland, June 14-22, 200
Jet Shapes in Opaque Media
We present general arguments, based on medium-induced radiative energy loss,
which reproduce the non-gaussian shapes of away-side di-jet azimuthal
correlations found in nucleus-nucleus collisions at RHIC. A rather simple
generalization of the Sudakov form factors to opaque media allowing an
effective description of the experimental data is proposed.Comment: 4 pages, 2 ps figure
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