12,682,118 research outputs found

    Two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

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    The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/388

    Nuclear Effects in Deep Inelastic Scattering of Charged-Current Neutrino off Nuclear

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    Nuclear effect in the neutrino-nucleus charged-Current inelastic scattering process is studied by analyzing the CCFR and NuTeV data. Structure functions F2(x,Q2)F_2(x,Q^2) and xF3(x,Q2)xF_3(x,Q^2) as well as differential cross sections are calculated by using CTEQ parton distribution functions and EKRS and HKN nuclear parton distribution functions, and compared with the CCFR and NuTeV data. It is found that the corrections of nuclear effect to the differential cross section for the charged-current anti-neutrino scattering on nucleus are negligible, the EMC effect exists in the neutrino structure function F2(x,Q2)F_2(x,Q^2) in the large xx region, the shadowing and anti-shadowing effect occurs in the distribution functions of valence quarks in the small and medium xx region,respectively. It is also found that shadowing effects on F2(x,Q2)F_2(x,Q^2) in the small xx region in the neutrino-nucleus and the charged-lepton-nucleus deep inelastic scattering processes are different. It is clear that the neutrino-nucleus deep inelastic scattering data should further be employed in restricting nuclear parton distributions.Comment: 24 pages, 5 figure

    Strange particle production in proton-proton collisions at s=0.9\sqrt{s}=0.9 TeV with ALICE at the LHC

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    The production of mesons containing strange quarks (Ks0^0_s, ϕ\phi) and both singly and doubly strange baryons (Λ\Lambda, Anti-Λ\Lambda, and Ξ\Xi+Anti-Ξ\Xi) are measured at central rapidity in pp collisions at s\sqrt{s} = 0.9 TeV with the ALICE experiment at the LHC. The results are obtained from the analysis of about 250 k minimum bias events recorded in 2009. Measurements of yields (dN/dy) and transverse momentum spectra at central rapidities for inelastic pp collisions are presented. For mesons, we report yields () of 0.184 ±\pm 0.002 stat. ±\pm 0.006 syst. for Ks0^0_s and 0.021 ±\pm 0.004 stat. ±\pm 0.003 syst. for ϕ\phi. For baryons, we find = 0.048 ±\pm 0.001 stat. ±\pm 0.004 syst. for Λ\Lambda, 0.047 ±\pm 0.002 stat. ±\pm 0.005 syst. for Anti-Λ\Lambda and 0.0101 ±\pm 0.0020 stat. ±\pm 0.0009 syst. for Ξ\Xi+Anti-Ξ\Xi. The results are also compared with predictions for identified particle spectra from QCD-inspired models and provide a baseline for comparisons with both future pp measurements at higher energies and heavy-ion collisions.Comment: 33 pages, 21 captioned figures, 10 tables, authors from page 28, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/387

    Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV

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    Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at sNN\sqrt{s_{_{\rm NN}}} = 2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in η<0.8|\eta|<0.8 and 0.3<pT<200.3 < p_T < 20 GeV/cc are compared to the expectation in pp collisions at the same sNN\sqrt{s_{\rm NN}}, scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor RAAR_{\rm AA}. The result indicates only weak medium effects (RAAR_{\rm AA} \approx 0.7) in peripheral collisions. In central collisions, RAAR_{\rm AA} reaches a minimum of about 0.14 at pT=6p_{\rm T}=6-7GeV/cc and increases significantly at larger pTp_{\rm T}. The measured suppression of high-pTp_{\rm T} particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb-Pb collisions at the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98

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    Simulated self-organization of a peer to peer awareness network

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    A simulation process and tool used to test and evaluate the algorithms necessary to optimally arrange a peer-to-peer distributed awareness system for Software Engineering

    The transaction pattern through automating TrAM

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    Transaction Agent Modelling (TrAM) has demonstrated how the early requirements of complex enterprise systems can be captured and described in a lucid yet rigorous way. Using Geerts and McCarthy’s REA (Resource-Events-Agents) model as its basis, the TrAM process manages to capture the ‘qualitative’ dimensions of business transactions and business processes. A key part of the process is automated model-checking, which CG has revealed to be beneficial in this regard. It enables models to retain the high-level business concepts yet providing a formal structure at that high-level that is lacking in Use Cases. Using a conceptual catalogue informed by transactions, we illustrate the automation of a transaction pattern from which further specialisations impart a tested specification for system implementation, which we envisage as a multi-agent system in order to reflect the dynamic world of business activity. It would furthermore be able to interoperate across business domains as they would share the generalised TM as a pattern.</p

    'Join us on our journey': Exploring the experiences of children and young people with type 1 diabetes and their parents

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    This paper focuses on children and young people with type 1 diabetes and on their parents, and their experiences of diabetes care provision. Nine acute hospitals in the Yorkshire and the Humber region, UK, were recruited to participate in a qualitative research study. Children and young people with type 1 diabetes, aged 6–25, and their parents (approximately 250 participants), took part in talking groups to find out about their experiences of diabetes care provision. Findings show that there are key areas for improvement in the future diabetes care provision for children and young people, including communication and support, schools, structured education and transition. These have important implications for practice and service redesign. This study is thought to be the first of its kind to consult with children, young people and parents to find out about their experiences of type 1 diabetes care provision. The research findings add to the current evidence base by highlighting the disparities in care, the urgent need for change in the way services are delivered and the involvement of service users in this process

    European Economic and Monetary Union: Transitional Issues and Third-Stage Dilemmas. European Policy Papers #4

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    This paper considers two kinds of issues facing EMU. One concerns qualifications and membership: how qualifications are evaluated and which member states are likely to meet the criteria set for membership in the third stage of EMU in 1999. The other concerns the capacity of member states, individually and collectively, to deal with economic policy after the advent of the third stage. In particular, will they be able to address the long-term problems of low growth and high unemployment that afflict so much of Europe? In regard to the first issue, the paper suggests, for supporters of EMU, some reason for optimism. It is very likely that the third stage of EMU will begin on the first day of 1999 and also that the "euro-zone" that comes into being on that day will, in all likelihood, include a large number of member states - almost certainly as many as 8 and probably as many as 10 or 11. On the second issue - the capacity of EMU to address the long-term problems of low growth and high unemployment - the paper suggests some reason for concern and pessimism. Most of the member states participating in the third stage of EMU are likely to continue experiencing low growth and high unemployment. Neither monetary policy nor exchange rate policy is likely to be applied so as to generate any significant increase in the long-term rate of economic growth or any decrease in the high levels of unemployment that now exist in most of the likely "euro-zone" members. Moreover, the Treaty creates no institutional capacity for collective action in economic policy that might enable the member states participating in EMU to redress those problems, and there seems to be little desire in the EU as a whole to create that institutional capacity
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