ALICE: Physics Performance Report, Volume II

Abstract

The possibility of colliding heavy nuclei with high luminosity at the Large Hadron Collider, expected to start operating in 2007 at CERN, offers a unique opportunity to investigate the behaviour of strongly interacting matter under extreme conditions of compression and heating. This will allow unprecedented tests of our understanding of equilibration processes and equilibrium states in Quantum Chromo-Dynamics (QCD), the fundamental theory of strong interactions. In particular, equilibrium QCD predicts that a phase transition to a plasma of deconfined partons, (the Quark-Gluon Plasma, or QGP), occurs at a critical energy density which is within experimental reach. Measurements at the LHC will probe extensively the properties of the bulk partonic matter produced in nucleus-nucleus collisions. The ALICE experiment-presently under construction-is the only LHC experiment designed specifically for the study of nucleus-nucleus collisions.This special issue of Journal of Physics G: Nuclear and Particle Physics is dedicated to the publication of the second volume of the ALICE Physics Performance Report. The first volume (published as volume 30, issue 11 of the journal) contained a general introductory part on the physics of nucleus-nucleus collisions at the LHC and a description of the experimental apparatus. In this second and last volume, the expected performance of the apparatus in the main areas of research of ALICE is analysed and discussed based on a series of representative measurements that were simulated and studied in detail.Through publication of the ALICE Physics Performance Report in Journal of Physics G, we hope to offer to the wider physics community an in-depth view of the research potential provided by this unique scientific instrument.

Transverse dynamics of Pb–Pb collisions at 40AGeV/cviewed by strange hadrons

“…The strange particle signals are extracted with the same procedure used at 158 A GeV/c [5,14] by applying similar geometric and kinematic constraints. The invariant mass spectra of π − π + , pπ, Λπ and ΛK combinations after all analysis cuts are shown in hyperon mass peaks at the nominal PDG values [17] and FWHMs of about 15 MeV/c 2 .…”

Strange and identified particle production with ALICE at the LHC

“…Indeed, an enhanced production of strange particles has been observed both at SPS [30,31] and RHIC [32] energies. The strangeness enhancements are defined as ratios of the strange particle yields measured in Pb-Pb collisions, normalized to the mean number of participant nucleons N part , to the corresponding quantities in pp interactions at the same energy.…”

Strangeness production at RHIC

“…Strangeness production in STAR beam energy scan Xianglei Zhu [13,[15][16][17]28], NA57 [8], NA49 [9,29], and Pb+Au collisions from CERES [11]. The rapidity ranges are |y| < 0.5 for STAR and NA57, |y| < 0.4 for NA49 Λ(Λ) and |y| < 0.5 for NA49 Ξ − (Ξ + ).…”

“…Strangeness enhancement in A+A with respect to p+p collisions has long been suggested as a signature of Quark-Gluon Plasma (QGP) formation in these collisions [2]. Until now, strangeness has been extensively measured in many experiments at different accelerator facilities [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Generally, the yields of strange hadrons in nuclear collisions are close to those expected from statistical models [20][21][22][23].…”