Narrow Results

Studies of light hadron and nuclei production are fundamental to characterize the hot and dense fireball created in ultra-relativistic heavy ion collisions and to investigate hadronisation mechanisms at the LHC. Observables investigated as a function of the charged particle multiplicity in proton-proton and proton-lead collisions have shown features not expected and qualitatively similar to what has been observed in larger size colliding systems. The ALICE experiment, exploiting its excellent tracking and PID capabilities, has performed an extensive and systematic study of strange and non-strange hadrons, short-lived hadron resonances and light (anti-)(hyper-)nuclei. A critical overview of these results will be presented through comparison with the statistical hadronisation model.

We review results obtained by the BRAHMS experiment at the Relativistic Heavy Ion Collider (RHIC) for the systems of Au + Au and Cu + Cu colliding at and at 62.4 GeV, and p + p colliding at . The observed number of charged particles produced per unit of rapidity in the central rapidity region indicates that a high energy density system is produced at the initial stage of the Au + Au reaction. Analysis of anti-particle to particle ratios as a function of rapidity and collision energy reveal that particle populations at the chemical freeze-out stage for heavy-ion reactions at and above SPS energies are controlled by the baryon chemical potential. We present rapidity dependent ratios within 0 < y < 3 for Au + Au and Cu + Cu at . The ratios are enhanced in nucleus-nucleus collisions as compared to p + p collisions. The particle ratios are discussed in terms of their system size and rapidity dependence. From comparison of R_AA for different systems and energies it is found that R_AA increases with decreasing collision energy, decreasing system size, and when going towards more peripheral collisions. However, R_AA shows only a very weak dependence on rapidity (for 0 < y < 3.2), both for pions and protons.

ALICE is the only LHC experiment dedicated to the study of the Quark-Gluon Plasma (QGP) which is expected to be created in heavy-ion collisions. Among the most promising observables, heavy quarkonia provide an essential probe for the characterization of the QGP thanks to their sensitivity to the earliest and hottest stages of the collision. Quarkonia measurement can be performed in the dimuon decay channel with the ALICE muon spectrometer at forward rapidity. It has been commissioned by means of cosmic rays and the first LHC beam injections in 2008 and has shown good performances for muon detection. This proceeding presents first quarkonia. results obtained in pp and Pb–Pb collisions.

For over 10 years the experimental operations at the Relativistic Heavy Ion Collider had provided access to the collisions data for a variety of beam species and center-of-mass energies. The scientific program that was initially devoted to the discovery of the deconfined state of partonic matter, the Quark Gluon Plasma, has expanded vastly, and now encompasses advanced studies of the properties of the novel matter created, as well as systematic studies of the QCD phase diagram, searching for an on-set of the deconfinement. In this work only selected recent results from RHIC are presented for the RHIC top energy (200 GeV) Au+Au data, and the medium properties illuminated through such studies will be discussed. Additionally, new measurements from d+Au data at the same center-of-mass energy, are included for a comparison to address the potential cold nuclear mater effects. Unexpected similarities in the di-hadron correlation measurements between the two systems are discussed in the context of possible constraints on the initial state properties.