The measurement of primary , , and production at mid-rapidity ( 0.5) in proton–proton collisions at 7 TeV performed with a large ion collider experiment at the large hadron collider (LHC) is reported. Particle identification is performed using the specific ionisation energy-loss and time-of-flight information, the ring-imaging Cherenkov technique and the kink-topology identification of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/ for pions, from 0.2 up to 6 GeV/ for kaons and from 0.3 up to 6 GeV/ for protons. The measured spectra and particle ratios are compared with quantum chromodynamics-inspired models, tuned to reproduce also the earlier measurements performed at the LHC. Furthermore, the integrated particle yields and ratios as well as the average transverse momenta are compared with results at lower collision energies.

The ALICE measurement of K(S)(0) and Λ production at midrapidity in Pb-Pb collisions at √(s(NN))=2.76 TeV is presented. The transverse momentum (p(T)) spectra are shown for several collision centrality intervals and in the p(T) range from 0.4 GeV/c (0.6 GeV/c for Λ) to 12 GeV/c. The p(T) dependence of the Λ/K(S)(0) ratios exhibits maxima in the vicinity of 3 GeV/c, and the positions of the maxima shift towards higher p(T) with increasing collision centrality. The magnitude of these maxima increases by almost a factor of three between most peripheral and most central Pb-Pb collisions. This baryon excess at intermediate p(T) is not observed in pp interactions at √s=0.9 TeV and at √s=7 TeV. Qualitatively, the baryon enhancement in heavy-ion collisions is expected from radial flow. However, the measured p(T) spectra above 2 GeV/c progressively decouple from hydrodynamical-model calculations. For higher values of p(T), models that incorporate the influence of the medium on the fragmentation and hadronization processes describe qualitatively the p(T) dependence of the Λ/K(S)(0) ratio.

Invariant differential yields of deuterons and antideuterons in pp collisions at √ s = 0.9, 2.76 and 7 TeV and the yields of tritons, 3 He nuclei, and their antinuclei at √ s = 7 TeV have been measured with the ALICE detector at the CERN Large Hadron Collider. The measurements cover a wide transverse momentum (p T ) range in the rapidity interval |y| < 0.5, extending both the energy and the p T reach of previous measurements up to 3 GeV/c for A = 2 and 6 GeV/c for A = 3. The coalescence parameters of (anti)deuterons and 3 He nuclei exhibit an increasing trend with p T and are found to be compatible with measurements in pA collisions at low p T and lower energies. The integrated yields decrease by a factor of about 1000 for each increase of the mass number with one (anti)nucleon. Furthermore, the deuteron-to-proton ratio is reported as a function of the average charged particle multiplicity at different center-of-mass energies.

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The production of prompt charmed mesons D 0 , D + and D * + , and their antiparticles, was measured with the ALICE detector in Pb-Pb collisions at the centre-of-mass energy per nucleon pair, √ s NN , of 2.76 TeV. The production yields for rapidity |y| < 0.5 are presented as a function of transverse momentum, p T , in the interval 1-36 GeV/c for the centrality class 0-10% and in the interval 1-16 GeV/c for the centrality class 30-50%. The nuclear modification factor R AA was computed using a proton-proton reference at √ s = 2.76 TeV, based on measurements at √ s = 7 TeV and on theoretical calculations. A maximum suppression by a factor of 5-6 with respect to binary-scaled pp yields is observed for the most central collisions at p T of about 10 GeV/c. A suppression by a factor of about 2-3 persists at the highest p T covered by the measurements. At low p T (1-3 GeV/c), the R AA has large uncertainties that span the range 0.35 (factor of about 3 suppression) to 1 (no suppression). In all p T intervals, the R AA is larger in the 30-50% centrality class compared to central collisions. The D-meson R AA is also compared with that of charged pions and, at large p T , charged hadrons, and with model calculations. The ALICE collaboration 36 IntroductionA state of strongly-interacting matter characterised by high energy density and temperature is predicted to be formed in ultra-relativistic collisions of heavy nuclei. According to calculations using Quantum Chromodynamics (QCD) on the lattice, these extreme conditions lead to the formation of a Quark-Gluon Plasma (QGP) state, in which quarks and gluons are deconfined, and chiral symmetry is partially restored (see e.g. [1][2][3][4]). Heavy quarks are produced in the hard scattering processes that occur in the early stage of the collision between partons of the incoming nuclei. Their production is characterised by a timescale ∆t < 1/(2 m c,b ), ∼ 0.1 fm/c for charm and ∼ 0.01 fm/c for beauty quarks, that is shorter than the formation time of the QGP medium, about 0.3 fm/c at Large Hadron Collider (LHC) energies [5]. They can successively interact with the constituents of the medium and lose part of their energy, via inelastic processes (gluon radiation) [6,7] or elastic scatterings (collisional processes) [8][9][10]. Energy loss can be studied using the -1 - JHEP03(2016)081nuclear modification factor R AA , which compares the transverse-momentum (p T ) differential production yields in nucleus-nucleus collisions (dN AA /dp T ) with the cross section in proton-proton collisions (dσ pp /dp T ) scaled by the average nuclear overlap function ( T AA )· dN AA /dp T dσ pp /dp T .(1.1)The average nuclear overlap function T AA over a centrality class is proportional to the number of binary nucleon-nucleon collisions per A-A collision in that class and it can be estimated via Glauber model calculations [11,12]. According to QCD calculations, quarks are expected to lose less energy than gluons because their coupling to the medium is smaller [6,7]. In the energy regime of the...