623 research outputs found

    Chiral Dynamics of scalar mesons: radiative ϕ\phi decay and σ\sigma in the medium through π0π0\pi^0 \pi^0 nuclear photoproduction

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    In order to assess the relevance of chiral dynamics in the scalar sector we address two recent problems: radiative decay of the ϕ\phi, for which there are quite recent data from Frascati, and the modification of the σ\sigma properties in the nuclear medium seen through the π0π0\pi^0 \pi^0 photoproduction in nuclei.Comment: Talk given at the High Energy Physics Workshop "Scalar Mesons: an Interesting Puzzle for QCD", Utica, New York, May 200

    Radiative vector meson decay

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    We study the radiative ρ\rho, ω\omega and ϕ\phi decay into π0π0γ\pi^0 \pi^0 \gamma and π0ηγ\pi^0 \eta \gamma taking into account mechanisms in which there are two sequential vector-vector-pseudoscalar or axial-vector--vector--pseudoscalar steps followed by the coupling of a vector meson to the photon, considering the final state interaction of the two mesons. Other mechanisms in which two kaons are produced through the same sequential mechanisms or from vector meson decay into two kaons which undergo final state interaction leading to the final pair of pions or π0η\pi^0 \eta, are also considered. The results of the parameter free theory, together with the theoretical uncertainties, are compared with the latest experimental results at Frascati and Novosibirsk.Comment: Prepared for the 10th International Symposium on Meson-Nucleon Physics and the Structure of the Nucleo

    Unitary chiral dynamics in J/ΨJ/\Psi decays into VPPVPP and the role of the scalar mesons

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    We make a theoretical study of the \J decays into ωππ\omega\pi\pi, ϕππ\phi\pi\pi, ωKKˉ\omega K \bar{K} and ϕKKˉ\phi K\bar{K} using the techniques of the chiral unitary approach stressing the important role of the scalar resonances dynamically generated through the final state interaction of the two pseudoscalar mesons. We also discuss the importance of new mechanisms with intermediate exchange of vector and axial-vector mesons and the role played by the OZI rule in the \J\phi\pi\pi vertex, quantifying its effects. The results nicely reproduce the experimental data for the invariant mass distributions in all the channels considered.Comment: Prepared for the 10th International Symposium on Meson-Nucleon Physics and the Structure of the Nucleo

    Isospin dependence of the three-nucleon force

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    We classify AA--nucleon forces according to their isospin dependence and discuss the most general isospin structure of the three--nucleon force. We derive the leading and subleading isospin--breaking corrections to the three--nucleon force using the framework of chiral effective field theory.Comment: 21 pages, 6 figure

    Rehabilitation of Left Homonymous Hemianopia with Adjacent Palomar Prism Technique and Visual Therapy on Line

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    We present a case of a female who suffered a right cerebral infarction, which caused left Homonymous hemianopia. She couldn't walk alone or do tasks of near vision, like reading. We used Palomar's prisms and visual therapy online with stimulation exercises and spatial localization for his rehabilitation. The patient was able to totally recover the central visual field in one year of treatment, being able to walk alone with the far visual aid

    SMOOTHERS AND THEIR APPLICATIONS IN AUTONOMOUS SYSTEM THEORY

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    Abstract. In this paper the author introduces the concept of smoother. Roughly speaking, a smoother is a pair (s, K) consisting of a continuous map s sending each point p of its domain into a closed neighborhood Vp of p, and an operator K that transforms any function f into another Kf being smoother than f. This property allows us to remove the effect of a perturbation P from the solutions of an autonomous system the vector field of which is modified by P

    Light scalar mesons in J/psi>J / psi ->NNmesonmesonmeson meson decays in a chiral unitary approach

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    We study the four-body decays J/ψNNˉJ/\psi\to N {\bar N} {\it meson meson} using a chiral unitary approach to account for the meson meson final state interaction (FSI). The calculation of the J/ψNNˉπ+πJ/\psi\to N \bar N \pi^+ \pi^- process properly reproduces the experimental data after taking the FSI of mesons and the contribution of intermediate ρ\rho meson into account. The isoscalar resonances σ\sigma, f0(980)f_0(980) and the isovector resonance a0(980)a_0(980) are generated through the FSI of the mesons in the channels J/ψNNˉπ0π0J/\psi\to N \bar N \pi^0 \pi^0 and J/ψNNˉπ0ηJ/\psi\to N \bar N \pi^0 \eta, respectively. We also calculate the two mesons invariant mass distribution and the partial decay width of J/ψNNˉK+KJ/\psi\to N \bar N K^+ K^- and J/ψNNˉK0Kˉ0J/\psi\to N \bar N K^0 {\bar K}^0, on which there is still no experimental data available.Comment: 13 pages, 5 figures in LaTex, version accepted by Phys. Rev.

    Superheroes, resiliencia y COVID-19

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