9,857 research outputs found

    Determining the Θ+\Theta^+ quantum numbers through a Kaon induced reaction

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    We study the K+p→π+KNK^+p\to \pi^+KN reaction with kinematical condition suited to the production of the Θ+\Theta^+ resonance. It is shown that in this reaction with the polarization experiment, a combined consideration of the strength at the peak and the angular dependence of cross section can help determine the Θ+\Theta^+ quantum numbers.Comment: 4 pages, 3 figures, Talk given at International Workshop PENTAQUARK04 at SPring-8, Japan, July 20-23, 200

    The scalar glueball spectrum

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    We discuss scenarios for scalar glueballs using arguments based on sum rules, spectral decomposition, the 1Nc\frac{1}{N_c} approximation, the scales of the strong interaction and the topology of the flux tubes. We analyze the phenomenological support of those scenarios and their observational implications. Our investigations hint a rich low lying glueball spectrum.Comment: 11 pages: New title, figure, table and a more detailed comparison with experiment

    Relationship between the column density distribution and evolutionary class of molecular clouds as viewed by ATLASGAL

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    We present the first study of the relationship between the column density distribution of molecular clouds within nearby Galactic spiral arms and their evolutionary status as measured from their stellar content. We analyze a sample of 195 molecular clouds located at distances below 5.5 kpc, identified from the ATLASGAL 870 micron data. We define three evolutionary classes within this sample: starless clumps, star-forming clouds with associated young stellar objects, and clouds associated with HII regions. We find that the N(H2) probability density functions (N-PDFs) of these three classes of objects are clearly different: the N-PDFs of starless clumps are narrowest and close to log-normal in shape, while star-forming clouds and HII regions exhibit a power-law shape over a wide range of column densities and log-normal-like components only at low column densities. We use the N-PDFs to estimate the evolutionary time-scales of the three classes of objects based on a simple analytic model from literature. Finally, we show that the integral of the N-PDFs, the dense gas mass fraction, depends on the total mass of the regions as measured by ATLASGAL: more massive clouds contain greater relative amounts of dense gas across all evolutionary classes.Comment: Accepted for publication in A&A (25th June 15) 23 pages, 12 figures. Additional appendix figures will appear in the journal version of this pape

    Evaluation of the ππ\pi\pi scattering amplitude in the σ\sigma-channel at finite density

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    The ππ\pi\pi scattering amplitude in the σ\sigma-channel is studied at finite baryonic density in the framework of a chiral unitary approach which successfully reproduces the meson meson phase shifts and generates the f0f_0 and σ\sigma resonances in vacuum. We address here a new variety of mechanisms recently suggested to modify the ππ\pi\pi interaction in the medium, as well as the role of the s−s-wave selfenergy, in addition to the p−p-wave, in the dressing of the pion propagators.Comment: 26 pages, 17 figure

    Out-of-plane seismic response of stone masonry walls: experimental and analytical study of real piers

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    This paper presents the application of an existing simplified displacement-based procedure to the characterization of the nonlinear force-displacement relationship for the out-of-plane behaviour of unreinforced traditional masonry walls. According to this procedure, tri-linear models based on three different energy based criteria were constructed and confronted with three experimental tests on existing stone masonry constructions. Moreover, a brief introduction is presented regarding the main characteristics of the in situ cyclic testing recently carried out using distributed loads, as well as results obtained during the experimental campaigns performed. The comparison between the experimental and the analytical results are presented and discussed

    Lepton flavor violation in SUSY left-right symmetric theories

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    The seesaw mechanism is the most popular explanation for the smallness of neutrino masses. However, its high scale makes direct tests impossible and only indirect signals at low energies are reachable for collider experiments. One of these indirect links with the high scale is lepton flavor violation (LFV). We discuss LFV decays of sleptons in the context of a SUSY left-right symmetric model that naturally incorporates the seesaw mechanism. This non-minimal embedding of the seesaw leads to observable LFV effects in the right-handed sleptons sector, contrary to minimal models where these are found to be totally negligible. Therefore, LFV observables can be used as a powerful tool to study physics right below the GUT scale.Comment: To appear in the proceedings of PASCOS 2010, the 16th International Symposium on Particles, Strings and Cosmology, Valencia, Spai
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