Heavy-ion physics studies for the Future Circular Collider

The Future Circular Collider (FCC) design study is aimed at assessing the physics potential and the technical feasibility of a new collider with centre-of-mass energies, in the hadron-hadron collision mode including proton and nucleus beams, more than seven-times larger than the nominal LHC energies. An electron-positron collider in the same tunnel is also considered as an intermediate step, which would provide the electron-hadron option in the long term. First ideas on the physics opportunities with heavy ions at the FCC are presented, covering the physics of Quark-Gluon Plasma, gluon saturation, photon-induced collisions, as well as connections with ultra-high-energy cosmic rays.

Suppression of high-pT heavy-flavour particles in Pb-Pb collisions at the LHC, measured with the ALICE detector

The ALICE experiment studies nucleus-nucleus collisions at the LHC in order to investigate the properties of QCD matter at extreme energy densities. The measurement of open charm and open beauty production allows one to probe the mechanisms of heavy-quark propagation, energy loss and hadronization in the hot and dense medium formed in high-energy nucleus-nucleus collisions. In particular, in-medium energy loss is predicted to be different for massless partons (light quarks and gluons) and heavy quarks at moderate momentum. The ALICE apparatus allows us to measure open heavy-flavour particles in several decay channels and with a wide phase-space coverage. We present the results on the nuclear modification factors for heavy-flavour particle production in Pb-Pb collisions at sqrtsNN=2.76 TeV. Using proton-proton and lead-lead collision samples at sqrts=2.76 and 7 TeV and at sqrtsNN=2.76 TeV, respectively, nuclear modification factors R_AA(pT) were measured for D mesons at central rapidity (via displaced decay vertex reconstruction), and for electrons and muons from heavy-flavour decays, at central and forward rapidity, respectively. A large suppression is observed, by a factor 2.5-4 in central Pb--Pb collisions with respect to the pp reference, in the high-pT region, indicating a strong in-medium energy loss of heavy quarks.

Heavy-flavour production in Pb-Pb collisions at the LHC, measured with the ALICE detector

We present the first results from the ALICE experiment on the nuclear modification factors for heavy-flavour hadron production in Pb-Pb collisions at sqrt{s_NN}=2.76 TeV. Using proton-proton and lead-lead collision samples at sqrt{s}=7 TeV and sqrt{s_NN}=2.76 TeV, respectively, nuclear modification factors R_AA(pt) were measured for D mesons at central rapidity (via displaced decay vertex reconstruction), and for electrons and muons, at central and forward rapidity, respectively.

First ALICE results from heavy-ion collisions at the LHC

The ALICE detector recorded Pb-Pb collisions at sqrtsNN = 2.76 TeV at the LHC in November-December 2010. We present the results of the measurements that provide a first characterization of the hot and dense state of strongly-interacting matter produced in heavy-ion collisions at these energies. In particular, we describe the measurements of the particle multiplicity, collective flow, Bose-Einstein correlations, high-momentum suppression, and their dependence on the collision centrality. These observables are related to the energy density, the size, the viscosity, and the opacity of the system. Finally, we give an outlook on the upcoming results, with emphasis on heavy flavour production.

Review on Heavy-Ion Physics

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 state 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 first physics results

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 energy 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.

Measurement of heavy-flavour production in proton-proton collisions at sqrt{s} = 7 TeV with ALICE

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 reference 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.

Preparation for heavy-flavour measurements with ALICE at the LHC

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.

Heavy ions and parton saturation from RHIC to LHC

The phenomenology of gluon saturation at small parton momentum fraction, Bjorken-x, in the proton and in the nucleus is introduced. The experimentally-accessible kinematic domains at the nucleus-nucleus colliders RHIC and LHC are discussed. Finally, the saturation hints emerging from measurements at RHIC and the perspectives for LHC are described.

Measurement of heavy-flavour production in ALICE

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 expected performance for the case of proton-proton collisions.