A. Kalweit

The ALICE TPC, a large 3-dimensional tracking device with fast readout for ultra-high multiplicity events

The design, construction, and commissioning of the ALICE Time-Projection Chamber (TPC) is described. It is the main device for pattern recognition, tracking, and identification of charged particles in the ALICE experiment at the CERN LHC. The TPC is cylindrical in shape with a volume close to 90 m(3) and is operated in a 0.5T solenoidal magnetic field parallel to its axis. In this paper we describe in detail the design considerations for this detector for operation in the extreme multiplicity environment of central Pb-Pb collisions at LHC energy. The implementation of the resulting requirements into hardware (field cage, read-out chambers, electronics), infrastructure (gas and cooling system, laser-calibration system), and software led to many technical innovations which are described along with a presentation of all the major components of the detector, as currently realized. We also report on the performance achieved after completion of the first round of stand-alone calibration runs and demonstrate results close to those specified in the TPC Technical Design Report

QCD and strongly coupled gauge theories: challenges and perspectives

We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.

Particle identification in the ALICE experiment

The particle identification capabilities of the ALICE experiment are unique among the four major LHC experiments. The working principles and excellent performance of the central barrel detectors in a high-multiplicity environment are presented as well as two physics examples: the extraction of transverse momentum spectra of charged pions, kaons, protons, and the observation of the nucleus.

Study of strange particle production in pp collisions with the ALICE detector

ALICE is well suited for strange particles production studies since it has very good reconstruction capabilities in the low transverse momentum (pt) region and it also allows to extend the identification up to quite high pt. Charged strange mesons (K, K−,) are reconstructed via energy loss measurements whereas neutral strange mesons (K0s ) and strange hyperons (Λ, Ξ, Ω) are identified via vertex reconstruction. All these particles carry important information: first, the measurement of production yields and the particle ratio within the statistical models can help to understand the medium created and secondly the dynamics at intermediate pt investigated via the baryon over meson ratio (Λ/K0s ) allows a better understanding of the hadronization mechanisms and of the underlying event processes. We present these two aspects of the strange particles analysis in pp collisions using simulated data. Study of strange particle production in pp collisions with the ALICE detector 2ALICE is well suited for strange particle production studies since it has very good reconstruction capabilities in the low transverse momentum (p t ) region and it also allows the identification to be extended up to quite high p t . Charged strange mesons (K + , K ― ) are reconstructed via energy loss measurements whereas neutral strange mesons (K 0 s ) and strange hyperons (A, Θ, Ω) are identified via vertex reconstruction. All these particles carry important information: firstly, the measurement of production yields and the particle ratio within the statistical models can help to understand the medium created, and secondly the dynamics at intermediate p t investigated via the baryon over meson ratio (Λ/K 0 s ) allows a better understanding of the hadronization mechanisms and of the underlying event processes. We present these two aspects of the strange particle analysis in pp collisions using simulated data.