2,642 research outputs found

    Hadron Production via e+e- Collisions with Initial State Radiation

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    A novel method of studying e+e- annihilation into hadrons using initial state radiation at e+e- colliders is described. After brief history of the method, its theoretical foundations are considered. Numerous experiments in which exclusive cross sections of e+e- annihilation into hadrons below the center-of-mass energy of 5 GeV have been measured are presented. Some applications of the results obtained to fundamental tests of the Standard Model are listed.Comment: 50 pages, 88 figures, accepted for publication in Rev. Mod. Phy

    Dynamics of a small neutrally buoyant sphere in a fluid and targeting in Hamiltonian systems

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    We show that, even in the most favorable case, the motion of a small spherical tracer suspended in a fluid of the same density may differ from the corresponding motion of an ideal passive particle. We demonstrate furthermore how its dynamics may be applied to target trajectories in Hamiltonian systems.Comment: See home page http://lec.ugr.es/~julya

    Measurement of hadron cross sections with the SND detector

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    New results on exclusive hadron production in e+e−e^+e^- annihilation obtained in experiments with the SND detector at the VEPP-2M and VEPP-2000 e+e−e^+e^- colliders are presented.Comment: 4 pages, 4 figures, presented at the 14th International Workshop on Meson Production, Properties and Interaction (MESON 2016), Cracow, Poland, 2nd - 7th June 201

    Study of the process e+e-\to \mu+\mu- in the energy region \sqrt{s}=980, 1040 -- 1380 MeV

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    The cross section of the process e+e-\to\mu+\mu- was measured in the SND experiment at the VEPP-2M e+e- collider in the energy region \sqrt{s}=980, 1040 -- 1380 MeV. The event numbers of the process e+e-\to\mu+\mu- were normalized to the integrated luminosity measured using e+e-\to e+e- and e+e-\to\gamma\gamma processes. The ratio of the measured cross section to the theoretically predicted value is 1.006\pm 0.007 \pm 0.016 and 1.005 \pm 0.007 \pm 0.018 in the first and second case respectively. Using results of the measurements, the electromagnetic running coupling constant \alpha in the energy region \sqrt{s}=1040 -- 1380 MeV was obtained = 134.1\pm 0.5 \pm 1.2 and this is in agreement with theoretical expectation.Comment: 29 pages, 23 figure

    Strangeness production in proton-proton and proton-nucleus collisions

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    In these lectures we discuss the investigation of the strange meson production in proton-proton (pppp) and in proton-nucleus (pApA) reactions within an effective Lagrangian model. The kaon production proceeds mainly via the excitations of N∗N^*(1650), N∗N^*(1710), and N∗N^*(1720) resonant intermediate nucleonic states, in the collision of two initial state nucleons. Therefore, the strangeness production is expected to provide information about the resonances lying at higher excitation energies. For beam energies very close to the kaon production threshold the hyperon-proton final state interaction effects are quite important. Thus, these studies provide a check on the models of hyperon-nucleon interactions. The in-medium production of kaons show strong sensitivity to the self energies of the intermediate mesons.Comment: 16 pages, 9 figures, Talk presented in the workshop on Hadron Physics, Puri, India, March 7-17,200
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