Light flavour hadron production in pp collisions at s\sqrt{s} = 13 TeV with ALICE

The ALICE detector has excellent Particle IDentification (PID) capabilities in the central barrel ($\lvert \eta \rvert <$ 0.9). This allows identified hadron production to be measured over a wide transverse momentum ($p_{\rm{T}}$) range, using different sub-detectors and techniques: their specific energy loss (d$E$/d$x$), the velocity determination via time-of-flight measurement, the Cherenkov angle or their characteristic weak decay topology. Results on identified light flavour hadron production at mid-rapidity measured by ALICE in proton-proton collisions at $\sqrt{s}$ = 13 TeV are presented and compared with previous measurements performed at lower energies. The results cover a wide range of particle species including long-lived hadrons, resonances and multi-strange baryons over the $p_{\rm{T}}$ range from 150 MeV/$c$ up to 20 GeV/$c$, depending on the particle species.Comment: 4 pages, 4 figures, Proceedings of Hot Quarks September 12-17, 2016, South Padre Island, Texas, US

Inclusive J/psi production at mid-rapidity in Pb-Pb collisions at sqrt(s_NN)= 5.02 TeV

Charmonium production is a key observable in the study of the properties of the Quark-Gluon Plasma created in ultrarelativistic heavy-ion collisions. The ALICE detector at the LHC provides unique capabilities at mid-rapidity to study charmonium production at low transverse momentum. J/psi mesons can be reconstructed via their dielectron decay channel. This thesis presents the measurement of inclusive J/psi production in Pb-Pb collisions at the center of mass energy of sqrt(s_NN)= 5.02 TeV. Due to the large integrated luminosity collected by ALICE during the second stage of operation of the LHC, the inclusive J/psi nuclear modification factor was measured as a function of centrality and as a function of transverse momentum in different centrality classes. The inclusive J/psi nuclear modification factor exhibits an enhancement towards lower transverse momentum, reaching a value around unity, and a suppression at high transverse momentum where energy-loss mechanisms are dominant. A qualitative description of the measurements is achieved by the models which include a large fraction of J/psi production by recombination. In addition, in peripheral collisions, the observation at mid-rapidity of an excess of J/psi with low transverse momentum (< 150 MeV/c) is presented

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

Peer reviewe

Identified particle production in pp, p-Pb, and Pb-Pb collisions measured with ALICE at LHC energies

The ALICE detector has excellent Particle IDentification (PID) capabilities in the central barrel (|η| < 0.9). This allows identified hadron production to be measured over a wide transverse momentum (p(T)) range, using different sub-detectors and techniques: their specific energy loss (dE/dx), the time of flight, the Cherenkov angle or their characteristic weak decay topology. Results on identified particle spectra and production yield ratios at mid-rapidity measured by ALICE in different colliding systems (pp, p-Pb and Pb-Pb) are presented and the similarities among them are discussed. For Pb-Pb collisions the nuclear modification factor as a function of p(T) is shown for different collision centralities

ALICE measurement of the J/ψJ/\psi nuclear modification factor at mid-rapidity in Pb–Pb collisions at sNN=\sqrt{{s}_{NN}}= 5.02 TeV

ALICE at the LHC provides unique capabilities to study charmonium production at low transverse momenta ( p T ). At central rapidity, ( |y|<0.8 ), ALICE can reconstruct J/ ψ via their decay into two electrons down to zero p T . Results at mid-rapidity on the inclusive J/ ψ nuclear modification factor RAA as a function of centrality in Pb-Pb collisions at sNN=5.02 TeV and comparisons to lower energies and models are shown. In addition, the yield of the J/ ψ produced with very low p T in the most peripheral collisions and the J/ ψ elliptic flow ( v2 ) are also presented

Measurement of Λ(1520) production in pp collisions at √s = 7 TeV and p–Pb collisions at √sNN = 5.02 TeV

The production of the Λ(1520) baryonic resonance has been measured at midrapidity in inelastic pp collisions at s√ = 7 TeV and in p-Pb collisions at sNN−−−√ = 5.02 TeV for non-single diffractive events and in multiplicity classes. The resonance is reconstructed through its hadronic decay channel Λ(1520) → pK− and the charge conjugate with the ALICE detector. The integrated yields and mean transverse momenta are calculated from the measured transverse momentum distributions in pp and p-Pb collisions. The mean transverse momenta follow mass ordering as previously observed for other hyperons in the same collision systems. A Blast-Wave function constrained by other light hadrons (π, K, K0S, p, Λ) describes the shape of the Λ(1520) transverse momentum distribution up to 3.5 GeV/c in p-Pb collisions. In the framework of this model, this observation suggests that the Λ(1520) resonance participates in the same collective radial flow as other light hadrons. The ratio of the yield of Λ(1520) to the yield of the ground state particle Λ remains constant as a function of charged-particle multiplicity, suggesting that there is no net effect of the hadronic phase in p-Pb collisions on the Λ(1520) yield