Comprehensive results on the production of unidentified charged particles, π

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.

Midrapidity production of π ± , K ± , and (p)p measured by the ALICE experiment at the CERN Large Hadron Collider, in Pb-Pb and inelastic pp collisions at √ s NN = 5.02 TeV, is presented. The invariant yields are measured over a wide transverse momentum (p T) range from hundreds of MeV/c up to 20 GeV/c. The results in Pb-Pb collisions are presented as a function of the collision centrality, in the range 0-90%. The comparison of the p T-integrated particle ratios, i.e., proton-to-pion (p/π) and kaon-to-pion (K/π) ratios, with similar measurements in Pb-Pb collisions at √ s NN = 2.76 TeV show no significant energy dependence. Blast-wave fits of the p T spectra indicate that in the most central collisions radial flow is slightly larger at 5.02 TeV with respect to 2.76 TeV. Particle ratios (p/π , K/π) as a function of p T show pronounced maxima at p T ≈ 3 GeV/c in central Pb-Pb collisions. At high p T , particle ratios at 5.02 TeV are similar to those measured in pp collisions at the same energy and in Pb-Pb collisions at √ s NN = 2.76 TeV. Using the pp reference spectra measured at the same collision energy of 5.02 TeV, the nuclear modification factors for the different particle species are derived. Within uncertainties, the nuclear modification factor is particle species independent for high p T and compatible with measurements at √ s NN = 2.76 TeV. The results are compared to state-of-the-art model calculations, which are found to describe the observed trends satisfactorily.

We report the measured transverse momentum (p T) spectra of primary charged particles from pp, p-Pb and Pb-Pb collisions at a center-of-mass energy √ s NN = 5.02 TeV in the kinematic range of 0.15 < p T < 50 GeV/c and |η| < 0.8. A significant improvement of systematic uncertainties motivated the reanalysis of data in pp and Pb-Pb collisions at √ s NN = 2.76 TeV, as well as in p-Pb collisions at √ s NN = 5.02 TeV, which is also presented. Spectra from Pb-Pb collisions are presented in nine centrality intervals and are compared to a reference spectrum from pp collisions scaled by the number of binary nucleon-nucleon collisions. For central collisions, the p T spectra are suppressed by more than a factor of 7 around 6-7 GeV/c with a significant reduction in suppression towards higher momenta up to 30 GeV/c. The nuclear modification factor R pPb , constructed from the pp and p-Pb spectra measured at the same collision energy, is consistent with unity above 8 GeV/c. While the spectra in both pp and Pb-Pb collisions are substantially harder at √ s NN = 5.02 TeV compared to 2.76 TeV, the nuclear modification factors show no significant collision energy dependence. The obtained results should provide further constraints on the parton energy loss calculations to determine the transport properties of the hot and dense QCD matter.

We report measurements of the production of prompt D 0 , D + , D * + and D + s mesons in Pb-Pb collisions at the centre-of-mass energy per nucleon-nucleon pair √ s NN = 5.02 TeV, in the centrality classes 0-10%, 30-50% and 60-80%. The D-meson production yields are measured at mid-rapidity (|y| < 0.5) as a function of transverse momentum (p T). The p T intervals covered in central collisions are: 1 < p T < 50 GeV/c for D 0 , 2 < p T < 50 GeV/c for D + , 3 < p T < 50 GeV/c for D * + , and 4 < p T < 16 GeV/c for D + s mesons. The nuclear modification factors (R AA) for non-strange D mesons (D 0 , D + , D * +) show minimum values of about 0.2 for p T = 6-10 GeV/c in the most central collisions and are compatible within uncertainties with those measured at √ s NN = 2.76 TeV. For D + s mesons, the values of R AA are larger than those of non-strange D mesons, but compatible within uncertainties. In central collisions the average R AA of non-strange D mesons is compatible with that of charged particles for p T > 8 GeV/c, while it is larger at lower p T. The nuclear modification factors for strange and non-strange D mesons are also compared to theoretical models with different implementations of in-medium energy loss.