The aim of this work is to explore possible medium modifications to the substructure of inclusive charged jets in Pb-Pb relative to proton-proton collisions by measuring a set of jet shapes. The set ...of shapes includes the radial moment, g, and the momentum dispersion pTD. They provide complementary information on the fragmentation and can help to discriminate between two different scenarios: intra-jet broadening or collimation as a result of jet quenching. The shapes are measured in Pb–Pb collisions at sNN=2.76 TeV with a constituent cutoff of 0.15 GeV/c and jet resolution R=0.2. New techniques for background subtraction are applied and a two-dimensional unfolding is performed to correct the shapes to particle level. The corrected jet shapes for jet pT 40≤pT,jet≤60 GeV/c are presented and discussed. The observed jet shape modifications suggest that the in-medium fragmentation is harder and more collimated than vacuum fragmentation as obtained by a PYTHIA calculation. The PYTHIA calculation is validated with proton-proton data at 7 TeV.
ALICE measured the nuclear modification factor (RAA) and elliptic flow (v2) of D mesons (D0, D+, D⁎+ and Ds+) in semi-central Pb–Pb collisions at sNN=5.02TeV. The increased amount of data in ...semi-central Pb–Pb events obtained with the LHC Run 2 provides access to more precise measurements for the RAA and the non-strange D-meson v2 with respect to Run 1 results, as well as to the first measurement of the Ds-meson v2 at LHC energies. The first application of the Event Shape Engineering technique in the analysis of the v2 coefficient of D0 and D+ mesons is also illustrated.
The ALICE collaboration has measured the inclusive charmonium production at forward rapidity in Pb–Pb and p–Pb collisions at sNN=5.02TeV and sNN=8.16TeV, respectively. In Pb–Pb collisions, the J/ψ ...and ψ(2S) nuclear modification factors (RAA), as well as the J/ψ elliptic flow (v2) and averaged squared transverse momentum (〈pT2〉), are presented. In p–Pb collisions, the J/ψ nuclear modification factor (RpPb) as a function of pt and rapidity is presented. In both systems, our measurements are compared to theoretical calculations and to the results at lower energies.
ALICE at the LHC provides unique capabilities to study charmonium production at low transverse momenta (pT). At central rapidity, (|y|<0.8), ALICE can reconstruct J/ψ via their decay into two ...electrons down to zero pT. 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 pT in the most peripheral collisions and the J/ψ elliptic flow (v2) are also presented.
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