265 research outputs found

    DETAIL RICHNESS OF PICTURES DEMONSTRATED BY MEDICAL X-RAY PICTURES

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    Matching problems in pulse power radial transmission lines

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    Elektrophysikalische Aquametrie

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    On the Particle Data Group evaluation of Psi' and chi_c Branching Ratios

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    I propose a new evaluation of ψ(2S)\psi'(2S) and χc(1P)\chi_c(1P) branching ratios which avoids the correlations affecting the current Particle Data Group evaluation. These correlations explain the apparent technique-dependent discrepancies between the available determinations of the B(χc(1P)ppˉ){\cal B}(\chi_c(1P)\to p\bar p) and Γ(χc(1P)γγ)\Gamma(\chi_c(1P)\to \gamma\gamma) under the hypotesis that the current values of the ψ(2S)χc(1P)γ\psi'(2S)\to\chi_c(1P)\gamma branching ratios are overestimated. In the process I also noticed that Particle Data Group has not restated many of the older measurements, when necessary, for the new value of B(J/ψl+l){\cal B}(J/\psi\to l^+l^-), which significantly affects the evaluation of some relevant ψ(2S)\psi'(2S) and χc(1P)\chi_c(1P) exclusive branching ratios.Comment: 13 pages. Revised version. Submitted to Phys. Rev.

    Electromagnetic form factors in the J/\psi mass region: The case in favor of additional resonances

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    Using the results of our recent analysis of e^+e^- annihilation, we plot the curves for the diagonal and transition form factors of light hadrons in the time-like region up to the production threshold of an open charm quantum number. The comparison with existing data on the decays of J/\psi into such hadrons shows that some new resonance structures may be present in the mass range between 2 GeVand the J/\psi mass. Searching them may help in a better understanding of the mass spectrum in both the simple and a more sophisticated quark models, and in revealing the details of the three-gluon mechanism of the OZI rule breaking in K\bar K channel.Comment: Formulas are added, typo is corrected, the text is rearranged. Replaced to match the version accepted in Phys Rev

    Possible large phase in psi(2S) -> 1-0- Decays

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    The strong and the electromagnetic amplitudes are analyzed on the basis of the measurements of J/psi, psi(2S) -> 1-0- in e+e- experiments. The currently available experimental information is revised with inclusion of the contribution from e+e- -> gamma * -> 1-0- . The study shows that a large phase around minus 90 degree between the strong and the electromagnetic amplitudes could not be ruled out by the experimental data for psi(2S).Comment: 4 page

    A Monte Carlo Study of the Dynamical-Flucautation Property of the Hadronic System Inside Jets

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    A study of the dynamical fluctuation property of jets is carried out using Monte Carlo method. The results suggest that, unlike the average properties of the hadronic system inside jets, the anisotropy of dynamical fluctuations in these systems changes abruptly with the variation of the cut parameter \yct. A transition point exists, where the dynamical fluctuations in the hadronic system inside jet behave like those in soft hadronic collisions, i.e. being circular in the transverse plan with repect to dynamical fluctuations. This finding obtained from Jetset and Herwig Monte Carlo is encouraged to be checked by experiments.Comment: 8 pages, 3 figure

    Quark-hadron-duality in the charmonium and upsilon system

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    In this work we discuss the practical and conceptual issues related to quark-hadron-duality in heavy-heavy systems. Recent measurements in the charmonium region allow a direct test of quark-hadron-duality. We present a formula for non-resonant background production in e^+ e^- \to D{\bar D} and extract the resonance parameters of the \psi(3S)-\psi(6S). The obtained results are used to investigate the upsilon energy range.Comment: 21 pages, 3 figures, references adde

    An SU(3) model for octet baryon and meson fragmentation

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    The production of the octet of baryons and mesons in e^+ e^- collisions is analysed, based on considerations of SU(3) symmetry and a simple model for SU(3) symmetry breaking in fragmentation functions. All fragmentation functions, D_q^h(x, Q^2), describing the fragmentation of quarks into a member of the baryon octet (and similarly for fragmentation into members of the meson octet) are expressed in terms of three SU(3) symmetric functions, \alpha(x, Q^2), \beta(x, Q^2), and \gamma(x, Q^2). With the introduction of an SU(3) breaking parameter, \lambda, the model is successful in describing hadroproduction data at the Z pole. The fragmentation functions are then evolved using leading order evolution equations and good fits to currently available data at 34 GeV and at 161 GeV are obtained.Comment: 24 pages LaTeX file including 11 postscript figure file

    Clocking hadronization in relativistic heavy ion collisions with balance functions

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    A novel state of matter has been hypothesized to exist during the early stage of relativistic heavy ion collisions, with normal hadrons not appearing until several fm/c after the start of the reaction. To test this hypothesis, correlations between charges and their associated anticharges are evaluated with the use of balance functions. It is shown that late-stage hadronization is characterized by tightly correlated charge/anticharge pairs when measured as a function of relative rapidity.Comment: 5 pages, 3 figure
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