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ALICE (A Large Ion Collider Experiment) is the dedicated heavy-ion experiment at the LHC. In fall 2010, Pb-Pb collisions were recorded at a center-of-mass energy of 2.76 TeV per nucleon pair, about 14 times higher than the energy achieved in A-A collisions at RHIC. The study of the produced hot and dense matter with an unprecedented energy density allows the characterization of the quark-gluon plasma, the deconfined state of quarks and gluons, predicted by QCD. The study of in-medium partonic energy loss allows insights into the density of the medium and the energy-loss mechanisms. This paper presents results based on inclusive spectra as well as two and more-particle correlations of charged particles. These are well suited to assess in-medium effects, ranging from the suppression of particles (RAA) and away-side jets (IAA) at high pT to longrange phenomena attributed to collective effects like the ridge at low pT. The analysis is discussed and the results are presented in the context of earlier RHIC measurements where appropriate. [ABSTRACT FROM AUTHOR]

A Large Ion Collider Experiment (ALICE) is one of the four experiments at the Large Hadron Collider (LHC), and it is dedicated to the study of ultra-relativistic heavy-ion collisions, with the goal of investigating the properties of the high-density state of QCD matter produced in such events. The first Pb-Pb collisions at a centre of mass energy of [formula] TeV per nucleon pair were delivered by LHC in November 2010. In Pb-Pb collisions heavy quarks are regarded as sensitive probes of the interaction dynamics between the parton and the medium produced in such collisions as they are produced on a very short time scale in the initial hard scattering processes and they follow all the evolution of the medium. At the energies available at the LHC charm is produced with large cross section and therefore it is possible to measure its production with good statistical precision. The study of open charm hadrons such as D+, D0, D*+, Ds and Λc in heavy ion collision is of particular interest because it can provide significant insight on the properties of the medium. Proton-proton collision data, that are being recorded at an energy of [formula] TeV since March 2010 provide an essential reference for these studies and allow to test perturbative QCD calculations in an unexplored energy domain. In this paper the analysis of D-meson production, carried out through a study of the hadronic decay channels in Pb-Pb collisions, will be presented in detail. The results for the reconstruction of D0, D+, D*+, and Ds hadrons at central rapidity will be shown along with the first results for the measurement of the D0 and D+ nuclear modification factor and prospects for azimuthal anisotropy studies. [ABSTRACT FROM AUTHOR]

In November 2010 the ALICE experiment at CERN has collected the first Pb-Pb collisions at [formula] TeV produced by the LHC. A first characterization of the hot and dense state of matter produced in this new energy domain became available shortly after the run. In this paper we present the results on charged-particle multiplicity, Bose-Einstein correlations, elliptic flow and their dependence on the collision centrality. Results from first measurements of strange and identified particle production and suppression of high-momentum hadrons with respect to pp collisions are also reported. [ABSTRACT FROM AUTHOR]

The Inner Tracking System of the ALICE experiment plays a crucial role in heavy flavour production measurements at central rapidity in Pb-Pb collisions thanks to its precise tracking and vertexing capabilities in a high-multiplicity environment. In view of the future luminosity increase at LHC, the ALICE experiment is developing an upgrade startegy where a new, more performant ITS is being proposed. Improving the tracking and particle identification performances, the resolution on the secondary vertices in the low momentum region as well as the read-out capabilities, the ITS will make new important measurements in the charm and beauty sector accessible in central heavy-ion collisions: the Λc baryon, B mesons and the total charm production cross section. In these proceeedings both the performances of a new ITS and some new accessible measurements of the heavy flavour physics in ALICE will be discussed. [ABSTRACT FROM AUTHOR]

The medium-modifications of processes characterized by the presence of a hard scale provide the most diverse tools to characterize the properties of the matter created in high-energy nuclear collisions. Indeed, jet quenching, the suppression of particles produced at high transverse momentum, has been established at RHIC almost a decade ago as one of the main tools in heavy-ion collisions. The melting of quarkonia is expected to provide also information about the temperature and the properties of the produced medium. The beginning of the LHC era for hot QCD studies starts with the first nuclear beams in 2010. The amount of information produced by this first run is overwhelming: The three experiments with nuclear program (ALICE, ATLAS and CMS) have provide new results in basically all subjects considered in previous experiments and have also shown the potential to make nuclear collisions at the TeV scale for the first time. I will review what the results from both RHIC and LHC imply for our understanding of hot and dense QCD matter from a theorists' perspective and how these new results change some of the concepts we developed in the last years. Particular attention is devoted to the case of jets, as the first data recently published from the LHC and the limitations of previous approaches call for a new theory of jets in a medium. [ABSTRACT FROM AUTHOR]

The first heavy-ion run at the LHC with Pb+Pb collisions at [formula] TeV took place in the fall of 2010. In a short and relatively low luminosity run, the three detectors, ALICE, ATLAS and CMS showcased an impressive performance and produced a wealth of a high quality results. This article compares the new LHC results with those accumulated over the last decade at RHIC, focussing on the quantitative and qualitative differences between the different energy regimes of these two facilities. [ABSTRACT FROM AUTHOR]

We will review the main results obtained so far within the ALICE experiment at the CERN's Large Hadron Collider. [ABSTRACT FROM AUTHOR]

One shows that relativistic heavy ion collisions could be used as an experimental probe to detect fundamental properties of spacetime long speculated about. The results rely on the recent proposal that magnetic fields of intensity much larger than that of magnetars should be produced at the beginning of the collisions and this could have an important impact on the experimental manifestation of a noncommutative spacetime. Indeed, in the noncommutative generalization of electrodynamics the interplay between a nonzero noncommutative parameter and an external magnetic field leads us to predict the production of lepton pairs of low invariant mass by free photons (an event forbidden by Lorentz invariant electrodynamics) in relativistic heavy ion collisions at present and future available energies. This unique channel can be clearly considered as a signature of noncommutativity. [ABSTRACT FROM AUTHOR]

The ALICE potentials in proton-proton collisions for the measurement of the fraction of J/ψ produced at central rapidity (|y|<0.9) in beauty hadrons semi-inclusive decays, namely B→J/ψX, is discussed. This measurement relies on the combined use of the Time Projection Chamber (TPC), for tracking and particle identification via dE/dx measurement; the Inner Tracking System (ITS) for tracking and detection of displaced vertices; the Transition Radiation Detector (TRD) for particle identification. The description of the analysis method developed and the discussion of the estimate for a total J/ψ statistics corresponding to one year of ALICE data taking in p-p collisions at s = 7 TeV is provided in the article. [ABSTRACT FROM AUTHOR]

The ALICE experiment is dedicated to the study of heavy-ion collisions at LHC energies. ALICE has a high-quality hadron identification system in the central region e.g. a Inner Tracking System, a large Time-Projection-Chamber, a Time-Of-Flight and the High Momentum Particle Identification Detector (HMPID). The ALICE HMPID detector has been designed to identify charged hadrons (ρ, K, p) in the momentum range 1s = 7 TeV and its future contribution to the ALICE physics programme, will be presented. [ABSTRACT FROM AUTHOR]

In this contribution, the cross sections for the competing channels for the heavy quark production in heavy ion collisions at the LHC are compared and investigated in detail. [ABSTRACT FROM AUTHOR]

A systematic measurement of the nuclear gluon distribution is of fundamental interest in understanding the parton structure of nuclei and to determine the initial conditions of the quark gluon plasma (QGP) predicted to be formed in central heavy ion collisions. At the moment the behavior of this distribution is completely undetermined by the fixed target experiments, with a possible improvement in the future electron-nucleus colliders. However, as the date of construction and start of operation of these colliders is still in debate, we need to obtain alternative searches to estimate the medium effects in the nuclear gluon distribution. An alternative is the study of the vector meson production in ultraperipheral heavy ion collisions at RHIC and LHC in order to constrain the nuclear medium effects present in the nuclear gluon distribution. In this contribution we present our main results for the J/Ψ photoproduction. [ABSTRACT FROM AUTHOR]

Studying the interaction of fast partons with the exotic matter produced in high-energy heavy ion collisions can help to elucidate the properties of the produced medium. The high resolution calorimeters and high precision silicon tracker in the Compact Muon Solenoid detector at the Large Hadron Collider (LHC) make it ideal for investigating these hard scattering processes. The first heavy ion run at the LHC provided PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV. Parton energy loss should result in a significant dijet transverse momentum imbalance, when comparing to a pp reference distribution. A large imbalance is, in fact, observed in the PbPb data, with the magnitude of the effect increasing with centrality. The details of the energy loss process were studied using the transverse momentum balance of charged tracks projected onto the direction of the leading jet. In contrast to pp collisions, low momentum particles emitted at large angles with respect to the jet axis constitute a large fraction of the momentum balance for asymmetric dijets in PbPb collisions. Fragmentation functions for leading and subleading jets were extracted and were observed to be unmodified compared to those in pp. These data provide a wealth of information on the propagation of hard partons through hot QCD matter. [ABSTRACT FROM AUTHOR]

In the Relativistic Heavy Ion Collider era the high-pT particle emerging from hard scattering became an important tool of exploration of excited nuclear medium formed in ultra-relativistic heavy ion collisions. Discovery of anomalous suppression of high-pT particle yield [1] together with an observation of disappearance of back-to-back hadron correlation in central Au+Au collisions in 2002 [2] were the key results interpreted as a manifestation of the deconfined QCD medium in heavy ion collisions. Analysis of the high-pT particle and jet production is already a standard experimental technique providing a test bench for pQCD description of the point-like constituent scattering in p+p collisions and sensitive probes of the excited nuclear medium in A+A collisions. [ABSTRACT FROM AUTHOR]