2,300 research outputs found

    In--Flight (K,pK^-,p) Reactions for the Formation of Kaonic Atoms and Kaonic Nuclei in Green function method

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    We study theoretically the kaonic atom and kaonic nucleus formations in the in--flight (K,pK^-,p) reactions using the Green function method, which is suited to evaluate formation rates both of stable and unstable bound systems. We consider 12^{12}C and 16^{16}O as the targets and calculate the spectra of the (K,pK^-,p) reactions. We conclude that a no peak structure due to kaonic nucleus formation is expected in the reaction spectra calculated with the chiral unitary kaon--nucleus optical potential. In the spectra with the phenomenological deep kaon--nucleus potential, we may have possibilities to observe some structures due to kaonic nucleus states. For all cases, we have peaks due to the kaonic atom formations in the reaction spectra.Comment: 10 pages, 9 figures, newly calculated results added, revisions and updated references, to appear in Physical Review

    Formation of Heavy Meson Bound States by Two Nucleon Pick-up Reactions

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    We develop a model to evaluate the formation rate of the heavy mesic nuclei in the two nucleon pick-up reactions, and apply it to the 6^6Li target cases for the formation of heavy meson-α\alpha bound states, as examples. The existence of the quasi-deuteron in the target nucleus is assumed in this model. It is found that the mesic nuclei formation in the recoilless kinematics is possible even for heavier mesons than nucleon in the two nucleon pick-up reactions. We find the formation rate of the meson-α\alpha bound states can be around half of the elementary cross sections at the recoilless kinematics with small distortions.Comment: 1 table, 10 figures, 8 page

    Recent topics of mesic atoms and mesic nuclei -- ϕ\phi mesic nuclei exist ?--

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    We study ϕ\phi-meson production in nuclei to investigate the in-medium modification of the ϕ\phi-meson spectral function at finite density. We consider (pˉ,ϕ{\bar p},\phi), (γ,p\gamma,p) and (π,n\pi^-,n) reactions to produce a ϕ\phi-meson inside the nucleus and evaluate the effects of the medium modifications to reaction cross sections. The structures of the bound states, ϕ\phi-mesic nuclei, are also studied. For strong absorptive interaction cases, we need to know the spectrum shape in a wide energy region to deduce the properties of ϕ\phi.Comment: Talk given at EXA08, Vienna, September 2008. To be published in the Proceedings, Hyperfine Interactions. 6 pages, 6 figure

    Formation of Deeply Bound Kaonic Atoms in (K^-,N) Reactions

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    We study theoretically the (K^-,N) reactions for the formation of the deeply bound kaonic atoms, which were predicted to be quasi--stable with narrow widths, using the Green function method. We consider various cases with different target nuclei and energies systematically and find the clear signals in the theoretical spectra for all cases considered in this article. The signals show very interesting structures, such as the RESONANCEDIPRESONANCE DIP instead of the resonance peak. We discuss the origins of the interesting structures and possibilities to get new information on the existence of the kaonic nuclei from the spectra of the atomic state formations.Comment: 11 pages, 9 figure

    The γγ\gamma \gamma decay of the f0(1370)f_0(1370) and f2(1270)f_2(1270) resonances in the hidden gauge formalism

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    Using recent results obtained within the hidden gauge formalism for vector mesons, in which the f0(1370)f_0(1370) and f2(1270)f_2(1270) resonances are dynamically generated resonances from the ρρ\rho \rho interaction, we evaluate the radiative decay of these resonances into γγ\gamma \gamma. We obtain results for the width in good agreement with the experimental data for the f2(1270)f_2(1270) state and a width about a factor five smaller for the f0(1370)f_0(1370) resonance, which would agree with preliminary results from the Belle collaboration, hinting at an order of magnitude smaller width for this resonance than for the f2(1270)f_2(1270).Comment: 7 pages, 9 figures, proof of gauge invariance adde

    Comment on "Localized behavior near the Zn impurity in YBa2Cu4O8 as measured by nuclear quadrupole resonance"

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    Williams and Kramer [Phys. Rev. B {\bf 64}, 104506 (2001)] have recently argued against the existence of staggered magnetic moments residing on several lattice sites around Zn impurities in YBCO superconductors. This claim, which is in line with an earlier publication by Williams, Tallon and Dupree [Phys. Rev. B {\bf 61}, 4319 (2000)], is however in contradiction with a large body of experimental data from different NMR groups. On the contrary, the authors argue in favor of a very localized spin and charge density on Cu sites first neighbors to Zn. We show that the conclusions of Williams and Kramer arise from erroneous interpretations of NMR and NQR data.Comment: 4 page
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