G. Paić

ALICE: Physics performance report, volume I

ALICE is a general-purpose heavy-ion experiment designed to study the physics of strongly interacting matter and the quark-gluon plasma in nucleus-nucleus collisions at the LHC. It currently includes more than 900 physicists and senior engineers, from both nuclear and high-energy physics, from about 80 institutions in 28 countries. The experiment was approved in February 1997. The detailed design of the different detector systems has been laid down in a number of Technical Design Reports issued between mid-1998 and the end of 2001 and construction has started for most detectors. Since the last comprehensive information on detector and physics performance was published in the ALICE Technical Proposal in 1996, the detector as well as simulation, reconstruction and analysis software have undergone significant development. The Physics Performance Report (PPR) will give an updated and comprehensive summary of the current status and performance of the various ALICE subsystems, including updates to the Technical Design Reports, where appropriate, as well as a description of systems which have not been published in a Technical Design Report.

Leading-particle suppression in high energy nucleus-nucleus collisions

Abstract.Parton energy loss effects in heavy-ion collisions are studied with the Monte Carlo program PQM (Parton Quenching Model) constructed using the BDMPS quenching weights and a realistic collision geometry. The merit of the approach is that it contains only one free parameter that is tuned to the high-pt nuclear modification factor measured in central Au-Au collisions at

Multiplicity and transverse energy flux in 16O+Pb at 200 GeV per nucleon

\sqrt{s_{\rm NN}} = 200

Photoelectron backscattering effects in photoemission from CsI into gas media

GeV. Once tuned, the model is consistently applied to all the high-pt observables at 200 GeV: the centrality evolution of the nuclear modification factor, the suppression of the away-side jet-like correlations, and the azimuthal anisotropies for these observables. Predictions for the leading-particle suppression at nucleon-nucleon centre-of-mass energies of 62.4 and 5500 GeV are presented. The limits of the eikonal approximation in the BDMPS approach, when applied to finite-energy partons, are discussed.

Neutral strange particle production in sulphur-sulphur and proton-sulphur collisions at 200 GeV/nucleon

Abstract First results from ultrarelativistic 16 O+Pb collisions at 200 GeV/nucleon are presented. The transverse energy E T in average central collisions is ≈ 75 GeV for the interval 2.2⩽ y ⩽3.8. A 16-fold convolution of the inelastic p+Au transverse energy spectrum, also measured at 200 GeV, reproduces the mean E T of 16 O+Pb. The amount of nuclear stopping power appears to be high.

Probing the space-time geometry of ultra-relativistic heavy-ion collisions

The photoemission from solid surfaces into gas is important in view of the application of solid photocathodes in fast-RICH devices. The photoemission from CsI into gas has been investigated in He-, Ar- and CH,-based gas mixtures as a function of the electric field at the photocathode surface. Measurements were made both in laboratory, with a UV source, and in a beam with a RICH detector. The results are interpreted in terms of current models of electron transport in gas. The electron collection efficiency, below gas ionization threshold, is reduced by backscattering. This phenomenon is particularly important in He-based gas mixtures. In CH, and Ar/CH, mixtures the backscattering is very low. At high electric field, under charge multiplication, a full collection efficiency, similar to that in vacuum, is obtained in all gases investigated. We discuss the parameters governing the choice of the gas mixture in this kind of photon detectors.

Final tests of the CsI-based Ring Imaging Detector for the ALICE experiment

AbstractThe production of Λ,

Negative particle production in nuclear collisions at 60 and 200 GeV/nucleon

\bar \Lambda