6,051 research outputs found

    Results on angular distributions of thermal dileptons in nuclear collisions

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    The NA60 experiment at the CERN SPS has studied dimuon production in 158 AGeV In-In collisions. The strong pair excess above the known sources found in the mass region 0.2<M<2.50.2<M<2.5 GeV has been previously interpreted as thermal radiation. In this paper results on the associated angular distributions for M<1M<1 GeV, as measured in the Collins-Soper reference frame, are presented. The structure function parameters λ\lambda, μ\mu, ν\nu are consistent with zero and the projected polar and azimuth angle distributions are uniform. The absence of any polarization is consistent with the interpretation of the excess dimuons as thermal radiation from a randomized system.Comment: 4 pages, 4 figures - To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse

    J/psi production in p-A and A-A collisions at fixed target experiments

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    Charmonia suppression is one of the main signatures for the formation of a deconfined medium. However, also nuclear effects, not related to the production of a hot medium, can affect the J/psi yield. The determination, from the study of p-A collisions, of the J/psi behaviour in nuclear matter is, therefore, extremely important to correctly quantify the amount of charmonia suppression induced by the deconfined medium. In this paper the new NA60 results collected at 158 GeV incident energy, i.e. under the same kinematical conditions as the In-In (NA60) and Pb-Pb (NA50) data, are presented and compared with p-A measurements from other fixed target experiments. Results on A-A collisions are also reviewed taking into account the new available information on the influence of cold nuclear matter on the J/psi production yield. Finally, results on the J/psi polarization are shown for p-A and A-A collisions.Comment: 8 pages, 8 figures - To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse

    J/Psi and Psi(2S) production in Pb-Pb collisions with the ALICE Muon Spectrometer at the LHC

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    Charmonium states are considered important signatures of the strongly interacting medium created in heavy-ion collisions. In the ALICE experiment, these probes can be investigated in the mu^+mu^- decay channel, in the forward rapidity region (2.5<y<4) down to zero transverse momentum. Results on charmonia production in Pb-Pb collisions at sqrt(s_NN)=2.76 TeV are presented. The centrality and transverse momentum dependence of the inclusive J/Psi nuclear modification factor are shown and compared with theoretical models. Finally, first ALICE results on the Psi(2S) production in Pb-Pb collisions are also discussed.Comment: 4 pages, 4 figures, contribution to the proceedings of the Quark Matter 2012 International Conference, Washington D.C., August 13-18, 201

    Dileptons and Direct Photons at SPS

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    The study of dilepton and direct photon emission was one of the main topics of the experimental program at the SPS devoted to the search of signals for QGP formation. Three generations of experiments, Helios-3, NA38/NA50, CERES and NA60 measured e+e- or mu+mu- production in various colliding systems and at different energies. While lepton pair production in p-A collisions was found to be reasonably well described by the expected sources, all experiments observed in nuclear collisions an excess of the yield above the extrapolation from p-A. As a result of this joint experimental effort we have currently a large amount of information characterizing this excess: its mass spectrum over the full range from 0.2 GeV/c^2 up to the J/psi, its transverse momentum spectra including their mass dependence, its angular distributions, its dependence on collision centrality over the complete range etc. Putting together all this information leads to the conclusion that what we observe is the long-sought thermal radiation from the fireball.Comment: 8 pages, 6 figures - To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse

    Responsible Research and Innovation between \u201cnew governance\u201d and fundamental rights

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    This chapter frames RRI as an emerging governance approach in the EU regulatory context. We argue that reference to fundamental rights makes RRI a distinctive approach to responsibility compared to other existing paradigms and that human rights, in particular those laid down in the Charter of Fundamental Rights of the European Union, are not necessarily a constraint but can instead be a catalyst of innovation. Eventually we maintain that a governance framework based on the complementarity between legal norms and voluntary commitments might successfully combine the respect of fundamental rights with the openness and flexibility of the innovation process

    Virtual Environments for Training: From Individual Learning to Collaboration with Humanoids

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    The next generation of virtual environments for training is oriented towards collaborative aspects. Therefore, we have decided to enhance our platform for virtual training environments, adding collaboration opportunities and integrating humanoids. In this paper we put forward a model of humanoid that suits both virtual humans and representations of real users, according to collaborative training activities. We suggest adaptations to the scenario model of our platform making it possible to write collaborative procedures. We introduce a mechanism of action selection made up of a global repartition and an individual choice. These models are currently being integrated and validated in GVT, a virtual training tool for maintenance of military equipments, developed in collaboration with the French company NEXTER-Group

    The Muon Spectrometer of the ALICE experiment

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    The main goal of the Muon Spectrometer of the ALICE experiment is the measurement of heavy quarks in pp, pA and AA collisions at LHC energies, via the muonic channel. Physics motivations, the apparatus and its physics performances are presented in this talk.Comment: 5 pages, 4 figures. Talk presented in Phase transitions in strongly interacting matter Prague, 23.8.-29.8. 2004 18th Nuclear Physics Division Conference of the EPS (NPDC18) Europhysics Conferenc
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