2,796 research outputs found

    Baryon resonance production in the π+d\pi+d reaction and search for η\eta-mesic nuclei at J-PARC

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    A double-scattering reaction π++dp+p+η\pi^+ + d\to p + p + \eta, where an η\eta meson is rescattered, may provide new information on the ηNηN\eta N\to \eta N scattering. An idea to measure this reaction is proposed. Moreover, experimental search for η\eta-mesic nuclei by the same (π,N)(\pi, N) reaction is discussed.Comment: Talk given at the Workshop on "Hadron and Nuclear Physics (HNP09)", RCNP, Osaka, Japan, Nov. 16-19, 2009. To appear in the proceeding

    Generation of focusing ion beams by magnetized electron sheath acceleration.

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    We present the first 3D fully kinetic simulations of laser driven sheath-based ion acceleration with a kilotesla-level applied magnetic field. The application of a strong magnetic field significantly and beneficially alters sheath based ion acceleration and creates two distinct stages in the acceleration process associated with the time-evolving magnetization of the hot electron sheath. The first stage delivers dramatically enhanced acceleration, and the second reverses the typical outward-directed topology of the sheath electric field into a focusing configuration. The net result is a focusing, magnetic field-directed ion source of multiple species with strongly enhanced energy and number. The predicted improvements in ion source characteristics are desirable for applications and suggest a route to experimentally confirm magnetization-related effects in the high energy density regime. We additionally perform a comparison between 2D and 3D simulation geometry, on which basis we predict the feasibility of observing magnetic field effects under experimentally relevant conditions

    Existence and Vanishing of the Breathing Mode in Strongly Correlated Finite Systems

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    One of the fundamental eigenmodes of finite interacting systems is the mode of {\em uniform radial expansion and contraction} -- the ``breathing'' mode (BM). Here we show in a general way that this mode exists only under special conditions: i) for harmonically trapped systems with interaction potentials of the form 1/rγ1/r^\gamma (γR0)(\gamma\in\mathbb{R}_{\neq0}) or log(r)\log(r), or ii) for some systems with special symmetry such as single shell systems forming platonic bodies. Deviations from the BM are demonstrated for two examples: clusters interacting with a Lennard-Jones potential and parabolically trapped systems with Yukawa repulsion. We also show that vanishing of the BM leads to the occurence of multiple monopole oscillations which is of importance for experiments

    Transit Time Effect on Voltage Contrast in the Stroboscopic Scanning Electron Microscope

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    Voltage contrast varies if the specimen voltage changes within the secondary electron transit time through the specimen electric field. This effect would affect the time resolution in stroboscopic scanning electron microscopy. The method to calculate the transit time effect that was described in a previous paper is reviewed. The calculated results agreed well with the experiment in which a specially designed specimen is used to estimate the applied voltage as exactly as possible
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