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ALICE is the heavy-ion experiment at the CERN Large Hadron Collider. The experiment continuously took data during the first physics campaign of the machine from fall 2009 until early 2013, using proton and lead-ion beams. In this paper we describe the running environment and the data handling procedures, and discuss the performance of the ALICE detectors and analysis methods for various physics observables.

The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at sqrt[s]=0.9 and 7 TeV during the initial running periods of the Large Hadron Collider. The measurement covers the transverse momentum interval 0.45

Measurements of π 0 and η inclusive spectra provide reference data for upcoming heavy ion runs, as well as a check on the applicability of perturbative QCD calculations at LHC energies. The high-resolution central tracking system of ALICE can be used to reconstruct π 0 and η through photon conversions, as an alternative to direct measurement in the ALICE Calorimeters. Knowledge of the ALICE material budget is crucial for the extraction of the absolute yield from the conversion technique. The statistics availible from this technique are comparable to that of the photon spectrometer (PHOS), and the reconstruction method can also be applied for Pb-Pb collisions. Moreover, the implementation of a photon conversion trigger in the High Level Trigger (HLT) framework gives the possibility of identifying π 0 and η candidates online, and increasing the statistics at higher momentum. The status of the π 0 meson reconstruction from photon conversions from p-p collisions at √ s = 900 GeV and √ s = 7 TeV is presented in this article.

We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at sqrt[S(NN)] =2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (|η|<0.8) and transverse momentum range 0.2