The project will be focussed on the use of high transverse
momentum electromagnetic probes (photons and dileptons) as tools
for investigating the early stages of a heavy-ion collision.
High-pT hadrons, charged and neutral, are created during the
initi al partonic collisions. Through their energy loss in a
deconfined medium, they probe the properties of the QGP. Neutral
pions can be reconstructed from their photonic decays. Direct
photons and dileptons carry unaltered information from the early
s tages of the reaction. Heavy quarkonia can be reconstructed
through their dileptonic decay channels. Their yields are
strongly influenced by the surrounding medium.
The LHC accelerator at CERN will start physics runs in 2007, with
p+p collisions at a center-of-mass energy of 14 TeV, followed by
Pb+Pb collisions at 5.5 TeV per nucleon pair.
The PHOS photon detector in ALICE is designed to measure direct
photons and neutral hadrons with diphotonic decays. The combination
of the ALICE Time Projection C hamber, Transition Radiation Detector
and Inner Tracking System with the High Level Trigger allows
fast selection of high-pT dilepton candidates, including direct
dileptons, heavy quarkonium decays and e+e-photon conversions.
The project will involve t he measurements of transverse momentum
spectra of neutral pions as a function of system size, in order
to probe the QGP opacity. Yields of heavy quarkonia will be
determined. Extraction of direct photons and dileptons will be
The fir st few years of the project will involve development
and optimization of reconstruction algorithms needed for the
measurements, and also detector tests. The last part of the project
period will be dedicated to the physics analysis of the first ALICE
data. Education of master, doctoral and postdoctoral candidates is
an integral part of the project.