1,036 research outputs found

    Asthma Symptoms, Lung Function, and Markers of Oxidative Stress and Inflammation in Children Exposed to Oil Refinery Pollution

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    none12mixedF. Rusconi; CATELAN, DOLORES; G. Accetta; M. Peluso; R. Pistelli; F. Barbone; E. Di Felice; A. Munnia; P. Murgia; L. Paladini; A. Serci; BIGGERI, ANNIBALEF., Rusconi; Catelan, Dolores; G., Accetta; M., Peluso; R., Pistelli; F., Barbone; E., Di Felice; A., Munnia; P., Murgia; L., Paladini; A., Serci; Biggeri, Annibal

    New Eco-gas mixtures for the Extreme Energy Events MRPCs: results and plans

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    The Extreme Energy Events observatory is an extended muon telescope array, covering more than 10 degrees both in latitude and longitude. Its 59 muon telescopes are equipped with tracking detectors based on Multigap Resistive Plate Chamber technology with time resolution of the order of a few hundred picoseconds. The recent restrictions on greenhouse gases demand studies for new gas mixtures in compliance with the relative requirements. Tetrafluoropropene is one of the candidates for tetrafluoroethane substitution, since it is characterized by a Global Warming Power around 300 times lower than the gas mixtures used up to now. Several mixtures have been tested, measuring efficiency curves, charge distributions, streamer fractions and time resolutions. Results are presented for the whole set of mixtures and operating conditions, %. A set of tests on a real EEE telescope, with cosmic muons, are being performed at the CERN-01 EEE telescope. The tests are focusing on identifying a mixture with good performance at the low rates typical of an EEE telescope.Comment: 8 pages, 6 figures, proceedings for the "XIV Workshop on Resistive Plate Chambers and Related Detectors" (19-23 February 2018), Puerto Vallarta, Jalisco State, Mexic

    The Extreme Energy Events HECR array: status and perspectives

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    The Extreme Energy Events Project is a synchronous sparse array of 52 tracking detectors for studying High Energy Cosmic Rays (HECR) and Cosmic Rays-related phenomena. The observatory is also meant to address Long Distance Correlation (LDC) phenomena: the network is deployed over a broad area covering 10 degrees in latitude and 11 in longitude. An overview of a set of preliminary results is given, extending from the study of local muon flux dependance on solar activity to the investigation of the upward-going component of muon flux traversing the EEE stations; from the search for anisotropies at the sub-TeV scale to the hints for observations of km-scale Extensive Air Shower (EAS).Comment: XXV ECRS 2016 Proceedings - eConf C16-09-04.

    Study of dimuon production in Indium-Indium collisions with the NA60 experiment

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    The NA60 experiment at the CERN-SPS is devoted to the study of dimuon production in heavy-ion and proton-nucleus collisions. We present preliminary results from the analysis of Indium-Indium collisions at 158 GeV per nucleon. The topics covered are low mass vector meson production, J/psi production and suppression, and the feasibility of the open charm measurement from the dimuon continuum in the mass range below the J/psi peak.Comment: Contribution at XXXXth Rencontres de Moriond, "QCD and High Energy Hadronic Interactions

    Measurements of the reaction pˉpϕη\bar{p}p \to \phi \eta of antiproton annihilation at rest at three hydrogen target densities

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    The proton-antiproton annihilation at rest into the ϕη\phi\eta final state was measured for three different target densities: liquid hydrogen, gaseous hydrogen at NTP and at a low pressure of 5 mbar. The yield of this reaction in the liquid hydrogen target is smaller than in the low-pressure gas target. The branching ratios of the ϕη\phi\eta channel were calculated on the basis of simultaneous analysis of the three data samples. The branching ratio for annihilation into ϕη\phi\eta from the 3S1^3S_1 protonium state turns out to be about ten times smaller as compared to the one from the 1P1^1P_1 state.Comment: 10 pages, 3 Postscript figures. Accepted by Physics Letters

    First results from the NA60 experiment at CERN

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    Since 1986, several heavy ion experiments have studied some signatures of the formation of the quark-gluon plasma and a few exciting results have been found. However, some important questions are still unanswered and require new measurements. The NA60 experiment, with a new detector concept that vastly improves dimuon detection in proton-nucleus and heavy-ion collisions, studies several of those open questions, including the production of open charm. This paper presents the experiment and some first results from data collected in 2002.Comment: Paper presented at the XXXVIII Rencontres de Moriond, QCD and High Energy Hadronic Interactions, Les Arcs, March 22-29, 2003. 4 pages, 6 figure

    Latest results from NA60

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    The NA60 experiment has measured the production of muon pairs and of charged particles in In+In collisions at a beam energy of 158 AGeV. For invariant dimuon masses below the phi the space-time averaged rho spectral function was isolated by a novel procedure. It shows a strong broadening but essentially no shift in mass. The production of J/psi was measured as a function of the collision centrality. As in previous experiments studying Pb+Pb collisions an anomalous supression is observed, setting in at approximately 90 participant nucleons. Using the charged particles the reaction plane was reconstructed. The elliptic flow of charged particles increases with pt showing a saturation for pt > 2GeV/c. For the first time azimuthal distributions for J/psi are shown.Comment: 9 pages, 11 figures, talk given at the conference "Strangeness in Quark Matter 2006 (SQM2006)", March 2006, Los Angeles, USA, accepted for publication in Journal of Physics

    ϕ\phi Meson Production in In-In Collisions and the ϕ\phi Puzzle

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    The NA60 experiment measured dimuon production in In-In collisions at 158 AGeV. This paper presents a high statistics measurement of ϕμμ\phi\to\mu\mu with the specific objective to provide insight on the ϕ\phi puzzle, i.e. the difference in the inverse TT slopes and absolute yields measured by NA49 and NA50 in the kaon and lepton channel, respectively. Transverse momentum distributions were studied as a function of centrality. The slope parameter TT shows a rapid increase with centrality, followed by a saturation. Variations of TT with the fit range of the order of 15 MeV were observed, possibly as a consequence of radial flow. The ϕ\phi meson yield normalized to the number of participants increases with centrality and is consistently higher than the yield measured by the NA49 experiment at any centrality.Comment: 4 Pages, 2 Figures. Proceedings of the 20th^{th} International Conference on Ultra-Relativistic Nucleus Nucleus Collision

    J/psi azimuthal anisotropy relative to the reaction plane in Pb-Pb collisions at 158 GeV per nucleon

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    The J/ψ\psi azimuthal distribution relative to the reaction plane has been measured by the NA50 experiment in Pb-Pb collisions at 158 GeV/nucleon. Various physical mechanisms related to charmonium dissociation in the medium created in the heavy ion collision are expected to introduce an anisotropy in the azimuthal distribution of the observed J/ψ\psi mesons at SPS energies. Hence, the measurement of J/ψ\psi elliptic anisotropy, quantified by the Fourier coefficient v2_2 of the J/ψ\psi azimuthal distribution relative to the reaction plane, is an important tool to constrain theoretical models aimed at explaining the anomalous J/ψ\psi suppression observed in Pb-Pb collisions. We present the measured J/ψ\psi yields in different bins of azimuthal angle relative to the reaction plane, as well as the resulting values of the Fourier coefficient v2_{2} as a function of the collision centrality and of the J/ψ\psi transverse momentum. The reaction plane has been estimated from the azimuthal distribution of the neutral transverse energy detected in an electromagnetic calorimeter. The analysis has been performed on a data sample of about 100 000 events, distributed in five centrality or pT_{\rm T} sub-samples. The extracted v2_{2} values are significantly larger than zero for non-central collisions and are seen to increase with pT_{\rm T}.Comment: proceedings of HP08 conference corrected a typo in one equatio

    Evidence for radial flow of thermal dileptons in high-energy nuclear collisions

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    The NA60 experiment at the CERN SPS has studied low-mass dimuon production in 158 AGeV In-In collisions. An excess of pairs above the known meson decays has been reported before. We now present precision results on the associated transverse momentum spectra. The slope parameter Teff extracted from the spectra rises with dimuon mass up to the rho, followed by a sudden decline above. While the initial rise is consistent with the expectations for radial flow of a hadronic decay source, the decline signals a transition to an emission source with much smaller flow. This may well represent the first direct evidence for thermal radiation of partonic origin in nuclear collisions.Comment: Accepted for publication in Physical Review Letter
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