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

Inclusive J/ψ production in pp collisions at √s=2.76 TeV

The ALICE Collaboration has measured inclusive J/ψ production in pp collisions at a center-of-mass energy √s=2.76 TeV at the LHC. The results presented in this Letter refer to the rapidity ranges |y|<0.9 and 2.5<y<4 and have been obtained by measuring the electron and muon pair decay channels, respectively. The integrated luminosities for the two channels are Linte=1.1 nb−1 and Lintμ=19.9 nb−1, and the corresponding signal statistics are NJ/ψe+e−=59±14 and NJ/ψμ+μ−=1364±53. We present dσJ/ψ/dy for the two rapidity regions under study and, for the forward-y range, d2σJ/ψ/dydpt in the transverse momentum domain 0<pt<8 GeV/c. The results are compared with previously published results at s=7 TeV and with theoretical calculations

Coherent J/ψ photoproduction in ultra-peripheral Pb–Pb collisions at √sNN=2.76 TeV

The ALICE Collaboration has made the first measurement at the LHC of J/ψ photoproduction in ultra-peripheral Pb–Pb collisions at sNN=2.76 TeV. The J/ψ is identified via its dimuon decay in the forward rapidity region with the muon spectrometer for events where the hadronic activity is required to be minimal. The analysis is based on an event sample corresponding to an integrated luminosity of about 55 μb−1. The cross section for coherent J/ψ production in the rapidity interval −3.6<y<−2.6 is measured to be dσJ/ψcoh/dy=1.00±0.18(stat)−0.26+0.24(syst) mb. The result is compared to theoretical models for coherent J/ψ production and found to be in good agreement with those models which include nuclear gluon shadowing