A. Dainese

Heavy-flavour production 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 produ...

Strangeness enhancements at central rapidity in 40 A GeV/c Pb-Pb collisions

Results are presented on the production of K0S, hyperons and antihyperons in Pb–Pb and p–Be interactions at 40 GeV/c per nucleon. The enhancement pattern follows the same hierarchy as seen in the higher energy data—the enhancement increases with the strangeness content of the hyperons and with the centrality of collision. The centrality dependence of the Pb–Pb yields and enhancements is steeper at 40 than at 158 A GeV/c. The energy dependence of strangeness enhancements at mid-rapidity is discussed.

Heavy ions at the Future Circular Collider

The Future Circular Collider (FCC) 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, seven times larger than the nominal LHC energies. Operating such machine with heavy ions is an option that is being considered in the accelerator design studies. It would provide, for example, Pb-Pb and p-Pb collisions at sqrt{s_NN} = 39 and 63 TeV, respectively, per nucleon-nucleon collision, with integrated luminosities above 30 nb^-1 per month for Pb-Pb. This is a report by the working group on heavy-ion physics of the FCC Study. First ideas on the physics opportunities with heavy ions at the FCC are presented, covering the physics of the Quark-Gluon Plasma, of gluon saturation, of photon-induced collisions, as well as connections with other fields of high-energy physics.

The ALICE Silicon Pixel Detector: readiness for the first proton beam

The Silicon Pixel Detector (SPD) is the innermost element of the ALICE Inner Tracking System (ITS). The SPD consists of two barrel layers of hybrid silicon pixels surrounding the beam pipe with a total of ≈ 107 pixel cells. The SPD features a very low material budget, a 99.9% efficient bidimensional digital response, a 12 μm spatial precision in the bending plane (r) and a prompt signal as input to the L0 trigger. The SPD commissioning in the ALICE experimental area is well advanced and it includes calibration runs with internal pulse and cosmic ray runs. In this contribution the commissioning of the SPD is reviewed and the first results from runs with cosmic rays and circulating proton beams are presented.

Centrality dependence of strange baryon yields in Pb-Pb collisions

New data on strange baryon yields in Pb–Pb interactions at 158 GeV/c per nucleon are presented as a function of the collision centrality. The possible onset of a deconfined phase when the collision involves from 50 to 100 wounded nucleons is discussed.

Heavy Ions at the Future Circular Collider

The Future Circular Collider (FCC) 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, seven times larger than the nominal LHC energies. Operating such machine with heavy ions is an option that is being considered in the accelerator design studies. It would provide, for example, Pb-Pb and p-Pb collisions at sqrt{s_NN} = 39 and 63 TeV, respectively, per nucleon-nucleon collision, with integrated luminosities above 30 nb^-1 per month for Pb-Pb. This is a report by the working group on heavy-ion physics of the FCC Study. First ideas on the physics opportunities with heavy ions at the FCC are presented, covering the physics of the Quark-Gluon Plasma, of gluon saturation, of photon-induced collisions, as well as connections with other fields of high-energy physics.

arXiv : Heavy ions at the Future Circular Collider

The Future Circular Collider (FCC) 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, seven times larger than the nominal LHC energies. Operating such machine with heavy ions is an option that is being considered in the accelerator design studies. It would provide, for example, Pb-Pb and p-Pb collisions at sqrt{s_NN} = 39 and 63 TeV, respectively, per nucleon-nucleon collision, with integrated luminosities above 30 nb^-1 per month for Pb-Pb. This is a report by the working group on heavy-ion physics of the FCC Study. First ideas on the physics opportunities with heavy ions at the FCC are presented, covering the physics of the Quark-Gluon Plasma, of gluon saturation, of photon-induced collisions, as well as connections with other fields of high-energy physics.

Alignment of the ALICE Tracking Detectors

ALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collision at LHC energies. The ALICE Inner Tracking System (ITS) consists of six cylindrical layers of silicon detectors with three different technologies: pixels in the two innermost layers (SPD), drifts in the two intermediate layers (SDD), and strips in the two outer ones (SSD). The number of geometrical parameters to be determined in the ITS alignment is about 13,000 and the target precision is below 10 μm. The alignment procedure is intended to make use both of tracks from cosmic-ray muons and tracks from pp collisions. The main alignment method uses the Millepede approach, where a global fit to all residuals is performed, extracting all the misalignment parameters simultaneously. In this contribution we present the results obtained for the ITS alignment using about 105 charged tracks from cosmic-rays that have been collected during summer 2008 with the ALICE magnetic field switched off.

The Silicon Pixel Detector for ALICE Experiment

The Inner Tracking System (ITS) of the ALICE experiment is made of position sensitive detectors which have to operate in a region where the track density may be as high as 50 tracks/cm2. To handle such densities detectors with high precision and granularity are mandatory. The Silicon Pixel Detector (SPD), the innermost part of the ITS, has been designed to provide tracking information close to primary interaction point. The assembly of the entire SPD has been completed.

Probing the QGP with charm at ALICE−LHC ∗

The exclusive reconstruction of D 0 mesons in the ALICE experiment allows to study the QCD energy loss of charm quarks in the deconfined quark–gluon plasma (QGP) medium expected to be produced in central nucleus–nucleus collisions at the Large Hadron Collider. The ALICE experiment [2] at the LHC will study nucleus–nucleus (AA) collisions at a centre-of-mass energy √ sNN = 5.5 TeV (for Pb–Pb) per nucleon– nucleon (NN) pair in order to investigate the properties of QCD matter at energy densities of few hundred times the density of atomic nuclei. In these conditions a deconfined state of quarks and gluons is expected to be formed [3]. Hard partons and heavy quarks, abundantly produced at LHC energies in initial hard scattering processes, are sensitive probes of the medium formed in the collision as they may lose energy by gluon bremsstrahlung while propagating through the medium itself. The attenuation (quenching) of leading hadrons and jets observed at RHIC [4] is thought to be due to such a mechanism. The large masses of the charm and beauty quarks make them qualitatively different probes, since, on well-established QCD grounds, in-medium energy loss off massive partons is expected to be significantly smaller than off ‘massless’ partons (light quarks and gluons). Therefore, a comparative study of the attenuation of massless and massive probes is a promising tool � This talk was presented in the New Talents Session at the “41 st International School of Subnuclear Physics, 2003” in Erice (Italy) and selected for publication in the proceedings of the School. The present paper is an extract from Ref. [1], where more details on the subject can be found.