(Abstract is abridged for arXiv.) Identified mid-rapidity particle spectra and freeze-out properties are presented for 200 GeV pp, 200 GeV dAu and 62.4 GeV Au-Au collisions, measured in the STAR-TPC. Evolution of the identified particle spectra ($pi^
{pm}$, $K^{pm}$, p and $overline{p}$) with charged particle multiplicity and event centrality is investigated in detail. Thermal model fits to the measured particle ratios yield a chemical freeze-out temperature $sim$ 155 MeV in 200 GeV pp, 200 GeV dAu and 62.4 GeV Au-Au collisions. The extracted chemical freeze-out temperature is close to the critical phase transition temperature predicted by lattice QCD calculations. The kinetic freeze-out temperature extracted from hydrodynamically motivated blast-wave models shows a continuous drop from pp, dAu and peripheral to central Au-Au collisions, while the transverse flow velocity increases from $sim$ 0.2 in pp to $sim$ 0.6 in central 200 GeV Au-Au collisions. The kinetic freeze-out parameters in 62.4 GeV and 200 GeV Au-Au collisions seem to be governed only by event multiplicity/centrality. In order to study the effect of resonance decays on the kinetic freeze-out parameters, the data are fitted with the blast-wave model including resonances. It is found that the thus extracted parameters are consistent with those obtained without including resonances, the resonance decays do not modify the spectral shapes significantly in the measured $p_{T}$ region in STAR.
ALICE has been specifically optimized to study heavy-ion collisions at the LHC, up to a charged particle density of 8000 per unit of rapidity in central heavy-ion collisions at $sqrt{s_{NN}}$ = 5.5 TeV. The High Momentum Particle Identification Detec
tor (HMPID) has a proximity focusing geometry with a liquid $rm C_{6}F_{14}$ Cherenkov radiator coupled to Multi-Wire Pad Chambers (MWPC) equipped with CsI photocathodes, over a total active area of 11 $rm m^2$. It has been designed to identify charged pions and kaons in the range 1 $leq p leq$ 3 GeV/$c$ and protons in the range 2 $leq p leq$ 5 GeV/$c$. The as-built detector and all relevant subsystems (gas, liquid $rm C_{6}F_{14}$, cooling and control) are described. Installation issues and first commissioning results are also presented.
Azimuthal di-hadron correlations play important role in the characterization of the medium created in heavy-ion collisions at RHIC. Moreover, as a novel phenomenon, strong modification of the away-side correlation is observed in Au+Au with respect to
p+p collisions. Below the exclusive jet reconstruction threshold at LHC, leading particle correlations will provide access to the regime where hard scatterings and bulk medium properties can be simultaneously studied. Leading particle correlations can be extended to very low transverse momenta via the tracking and particle identification capabilities of ALICE, to the coalescence and hydrodynamic domains. In preparation for the first p+p and Pb+Pb collisions of LHC, we present prospects on leading particle correlations with identified particles in ALICE.
The LHC will deliver unexplored energy regimes for proton-proton and heavy-ion collisions. As shown by the RHIC experiments, particle identification over a large momentum range is essential to disentangle physics processes, especially in the intermed
iate p$_T$ (1 $<p_{T}<5$ GeV/c) region. The novel design of the High-Momentum Particle Identification Detector (HMPID), based on large surface CsI photocathodes, is able to identify $pi^{pm}$, $K^{pm}$, $p$ and $bar{p}$ in the momentum region where bulk medium properties and hard scatterings interplay. Furthermore, measurement of resonance particles such as the $phi to K^+K^-$ could provide information on the system evolution. The HMPID layout and segmentation are optimized to study particle correlations at high momenta describing the early phase and the dynamical evolution of the collision. At LHC, the increased hard cross section will significantly be enhanced compared to RHIC. Jet reconstruction via Deterministic Annealing can address jet quenching and detailed measurements of jet properties. In this paper, we present these selected topics from the possible HMPID contributions to the physics goals of LHC.
