17 research outputs found

    Partial Wave Analysis of the Reaction p(3.5GeV)+ppK+Λp(3.5 GeV)+p \to pK^+\Lambda to Search for the "ppKppK^-" Bound State

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    Employing the Bonn-Gatchina partial wave analysis framework (PWA), we have analyzed HADES data of the reaction p(3.5GeV)+ppK+Λp(3.5GeV)+p\to pK^{+}\Lambda. This reaction might contain information about the kaonic cluster "ppKppK^-" via its decay into pΛp\Lambda. Due to interference effects in our coherent description of the data, a hypothetical KNN\overline{K}NN (or, specifically "ppKppK^-") cluster signal must not necessarily show up as a pronounced feature (e.g. a peak) in an invariant mass spectra like pΛp\Lambda. Our PWA analysis includes a variety of resonant and non-resonant intermediate states and delivers a good description of our data (various angular distributions and two-hadron invariant mass spectra) without a contribution of a KNN\overline{K}NN cluster. At a confidence level of CLs_{s}=95\% such a cluster can not contribute more than 2-12\% to the total cross section with a pK+ΛpK^{+}\Lambda final state, which translates into a production cross-section between 0.7 μb\mu b and 4.2 μb\mu b, respectively. The range of the upper limit depends on the assumed cluster mass, width and production process.Comment: 7 Pages, 5 Figure

    Origin of the low-mass electron pair excess in light nucleus-nucleus collisions

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    We report measurements of electron pair production in elementary p+p and d+p reactions at 1.25 GeV/u with the HADES spectrometer. For the first time, the electron pairs were reconstructed for n+p reactions by detecting the proton spectator from the deuteron breakup. We find that the yield of electron pairs with invariant mass Me+e- > 0.15 GeV/c2 is about an order of magnitude larger in n+p reactions as compared to p+p. A comparison to model calculations demonstrates that the production mechanism is not sufficiently described yet. The electron pair spectra measured in C+C reactions are compatible with a superposition of elementary n+p and p+p collisions, leaving little room for additional electron pair sources in such light collision systems.Comment: 11 pages, 2 figures, \usepackage{epsfig

    Creation of the precision magnetic spectrometer SCAN-3

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    The new JINR project [1] is aimed at studies of highly excited nuclear matter created in nuclei by a high-energy deuteron beam. The matter is studied through observation of its particular decay products - pairs of energetic particles with a wide opening angle, close to 180°. The new precision hybrid magnetic spectrometer SCAN-3 is to be built for detecting charged (π±, K±, p) and neutral (n) particles produced at the JINR Nuclotron internal target in dA collisions. One of the main and complex tasks is a study of low-energy ηA interaction and a search for η-bound states (η-mesic nuclei). Basic elements of the spectrometer and its characteristics are discussed in the article

    Modern methodological approaches to the assessment of hypoxia tolerance and physical working capacity prediction in the mountains (literature review)

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    To this date, the issue of methods development for evaluation of human physical tolerance to exercises in the mountains remains relevant. In this regard, the authors consider the current methodological approaches to the assessment of hypoxia tolerance: methods based on recording of changes in genetic and biochemical hypoxia markers; functional tests (Stange’s, Serkin’s, Rosenthal’s tests, etc.), accompanied by short-term acute hypoxia, with and without respect to anthropometric data; methods for evaluation of hypoxia tolerance based on breathing the oxygen-reduced air without performing physical exercise (anoxic hypoxia, hypobaric hypoxia) and with it (anoxic hypoxia and “load” hypoxia). Based on the results of the analysis of literature data, the main positive and negative aspects of these methods are noted, and the need to develop a methodology that includes a full assessment of the response of the cardiorespiratory system under hypoxic conditions using cardiopulmonary exercise testing is shown

    Creation of the precision magnetic spectrometer SCAN-3

    No full text
    The new JINR project [1] is aimed at studies of highly excited nuclear matter created in nuclei by a high-energy deuteron beam. The matter is studied through observation of its particular decay products - pairs of energetic particles with a wide opening angle, close to 180°. The new precision hybrid magnetic spectrometer SCAN-3 is to be built for detecting charged (π±, K±, p) and neutral (n) particles produced at the JINR Nuclotron internal target in dA collisions. One of the main and complex tasks is a study of low-energy ηA interaction and a search for η-bound states (η-mesic nuclei). Basic elements of the spectrometer and its characteristics are discussed in the article

    Dilepton Production at SIS Energies Studied with HADES

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    One of the main goals of the HADES experiment is to achieve a detailed understanding of dielectron emission from hadronic systems at moderate bombarding energies. Results obtained on electron pair production in elementary N+N collisions pave the way to a better understanding of the origin of the pair excess seen in heavy-ion collisions. This puzzling excess, reported first by the former DLS experiment, is now being investigated systematically by HADE
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