Collisions of heavy ions (nuclei) at ultra-relativistic energies (sqrt(s_NN) >> 10 GeV per nucleon-nucleon collision in the centre of mass system) are regarded as a unique tool to produce in the laboratory a high energy density and high temperature s
tate of strongly-interacting matter. In this short review, we will discuss the expected features of this hot and dense state, describe indications on its properties emerged from the experimental programs at the CERN-SPS and BNL-RHIC accelerators, and finally outlook the perspectives for the forthcoming heavy-ion runs at the CERN-LHC.
ALICE is the dedicated heavy-ion experiment at the Large Hadron Collider. The experiment has also a broad program of QCD measurements in proton-proton (pp) collisions, which have two-fold interest: the study of particle production at the highest ener
gy frontier, and the definition of references for the corresponding measurements in the upcoming Pb-Pb run. We present the first results on the pseudorapidity and transverse-momentum dependence of charged particle production in pp collisions at LHC energies, on the anti-p/p ratio and on the Bose-Einstein particle correlations. As an outlook, we report on the status of the ongoing analyses for strangeness and heavy-flavour production measurements.
The measurement of the heavy-flavour production cross sections in pp collisions at the LHC will allow to test perturbative QCD calculations in a new energy domain. Moreover, within the physics program of the ALICE experiment, it will provide the refe
rence for the study of medium effects in Pb-Pb collisions, where heavy quarks are regarded as sensitive probes of parton-medium interaction dynamics. We present the status and first preliminary results of charm and beauty production measurements with the ALICE experiment, using hadronic D meson decays and semi-leptonic D and B meson decays, including the first cross section measurement of muons from heavy flavour decays at forward rapidity. We also describe the preliminary cross section measurement for J/psi production, obtained using the di-electron decay channel at central rapidity and the di-muon decay channel at forward rapidity.
ALICE will study nucleus-nucleus and proton-proton collisions at the LHC. The main goal of the experiment is to investigate the properties of QCD matter at the extreme energy densities that will be reached in Pb-Pb collisions. Heavy quarks (charm and
beauty) are regarded as powerful tools for this study. After briefly reviewing the ALICE heavy-flavour program, we will describe the preparation for the first measurements to be performed with pp collisions.
The ALICE experiment, currently in the commissioning phase, will study nucleus-nucleus and proton-proton collisions at the CERN Large Hadron Collider (LHC). We review the ALICE heavy-flavour physics program and present a selection of results on the e
xpected performance for the case of proton-proton collisions.
We study the nuclear modification factors RAA and RCP of the high transverse momentum 5<pt<60 GeV/c distribution of muons in Pb--Pb collisions at LHC energies. We consider two pseudo-rapidity ranges covered by the LHC experiments: $|eta|<2.5$ and $2.
5<eta<4$. Muons from semi-leptonic decays of heavy quarks (c and b) and from leptonic decays of weak gauge bosons (W and Z) are the main contributions to the muon pt distribution above a few GeV/c. We compute the heavy quark contributions using available pQCD-based programs. We include the nuclear shadowing modification of the parton distribution functions and the in-medium radiative energy loss for heavy quarks, using the mass-dependent BDMPS quenching weights. Muons from W and Z leptonic decays, that dominate the yield at high pt, can be used as a medium-blind reference to observe the medium-induced suppression of beauty quarks.
The Large Hadron Collider (LHC), where lead nuclei will collide at the unprecedented c.m.s. energy of 5.5 TeV per nucleon-nucleon pair, will offer new and unique opportunities for the study of the properties of strongly interacting matter at high ene
rgy density over extended volumes. We will briefly explain why heavy-flavour particles are well-suited tools for such a study and we will describe how the ALICE experiment is preparing to make use of these tools.
