No Arabic abstract
The discovery of correlations between particles separated by several units of pseudorapidity in high-multiplicity pp and p-Pb collisions, reminiscent of structures observed in Pb-Pb collisions, was a challenge to traditional ideas about collectivity in heavy ion collisions. In order to further explore long-range correlations and provide information to theoretical models, correlations between forward trigger muons and mid-rapidity associated hadrons were measured in p-Pb collisions at $sqrt{s_{mbox{NN}}} = 5.02~mbox{TeV}$. The results demonstrate that the nearside and awayside ridges extend to $Deltaeta sim pm 5$ and that the $v_2$ of muons, obtained from subtracting the correlation functions in high- and low-multiplicity events, is $(16pm6)%$ higher in the Pb-going than in the p-going direction. The results are compared with AMPT simulations.
The ALICE experiment has measured quarkonia production in pp and Pb-Pb collisions at the CERN LHC, in the rapidity ranges |y|<0.9 and 2.5<y<4. Quarkonia are considered to be a sensitive probe of deconfinement, and a detailed differential study of their yields can give important information on the properties of the medium created in heavy-ion collisions. In this paper, we will mainly discuss the centrality dependence of the J/psi nuclear modification factors, as well as their p_T and y dependence in bins of centrality, which will be then compared to theoretical models. Preliminary results on the J/psi elliptic flow and on psi(2S) production will also be shown.
Angular correlations are a sensitive probe of the transport properties of the system produced in nucleus-nucleus collisions. Similar studies performed in p-Pb collisions have recently revealed intriguing features as well. In this article, we review the latest results on charged and identified particle correlations obtained with the ALICE detector at the LHC in both Pb-Pb and p-Pb events.
Polarized proton-proton collisions at the Relativistic Heavy Ion Collider (RHIC) provide unique opportunities to study the spin structure of the nucleon. We will highlight recent results on the nucleon spin structure from the STAR and PHENIX experiments at RHIC: (1) A sizable gluon polarization in the proton is measured with longitudinal double spin asymmetries of jet and hadron production; (2) Longitudinal single spin asymmetries in W boson production improve constraints on the sea quark polarization. The new spin asymmetry results for W boson confirmed the SU(2) flavor asymmetry of the light sea quark polarization in the proton; (3) Transverse spin effects in hadronic systems offer new implications on parton distribution functions in the collinear and transverse momentum dependent frameworks. We will also discuss near term plans for the STAR forward detector upgrade and prospects for proton-proton and proton-ion collisions in the years beyond 2021 at STAR.
In these proceedings, we report on the production of various open heavy-flavor hadrons and quarkonia in Au+Au collisions at sNN = 200GeV from the STAR experiment.
A precise measurement of the heavy-flavor production cross-sections in pp collisions is an essential baseline for the heavy-ion program. In addition it is a crucial test of pQCD models in the new energy regime at LHC. ALICE measures the muons from the decay of charmonium resonances and from the semileptonic decay of heavy-flavored hadrons in its forward (-4.0 $<$ $eta$ $<$ -2.5) Muon Spectrometer. We discuss the status of the detector and present results of data taken in pp collisions at $sqrt{s}$=7 TeV.