1,369 research outputs found

    Magnetic Moments of Heavy ΞQ\Xi_{Q} Baryons in Light Cone QCD Sum Rules

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    The magnetic moments of heavy ΞQ\Xi_{Q} baryons containing a single charm or bottom quark are calculated in the framework of light cone QCD sum rules method. A comparison of our results with the predictions of the quark models is presented.Comment: 26 Pages, 8 Figures and 1 Tabl

    Rare Radiative BcDs1(2460)γB_{c}\rightarrow D_{s1}(2460)\gamma Transition in QCD

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    We investigate the radiative BcDs1γB_{c} \to D_{s1} \gamma transition in the framework of QCD sum rules. In particular, we calculate the transition form factors responsible for this decay in both weak annihilation and electromagnetic penguin channels using the quark condensate, mixed and two-gluon condensate diagrams as well as propagation of the soft quark in the electromagnetic field as non-perturbative corrections. These form factors are then used to estimate the branching ratios of the channels under consideration. The total branching ratio of the BcDs1γB_{c} \to D_{s1} \gamma transition is obtained to be in order of 10510^{-5}, and the dominant contribution comes from the weak annihilation channel.Comment: 24 Pages and 3 Figure

    Vertical dipoles to detect self potential signals in a seismic area of southern Italy: Tito station

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    International audienceSince 2000 the Institute of Methodologies for the Environmental Analysis (National Council of Research, Tito, Italy) installed a geophysical monitoring network able to detect geoelectric, geochemic and seismometric parameters in seismic areas of southern Italy. During this period a very large data-base of geophysical time series has been organized and it is actually available to assess robust statistical methodologies to identify geophysical anomalous patterns linked with local seismicity. To better understand the influence of rain and cultural noise on geoelectrical signals (Self Potential), during May 2004 we drilled in Tito station a 20 m-depth hole to measure the SP vertical component. The array is characterized by five Pb-PbCl2 electrodes put at different depths. The common electrode is fixed at 20 m. In this work we present some electrical anomalies probably correlated with local seismic activity on vertical dipoles recorded in Tito station

    Strong Interactions at Low Energy

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    The lectures review some of the basic concepts relevant for an understanding of the low energy properties of the strong interactions: chiral symmetry, spontaneous symmetry breakdown, Goldstone bosons, quark condensate. The effective field theory used to analyze the low energy structure is briefly sketched. As an illustration, I discuss the implications of the recent data on the decay KππeνK\to \pi\pi e\nu for the magnitude of the quark condensate.Comment: Lectures given at the school of physics "Understanding the structure of hadrons", Prague, July 2001, 20 p

    Chiral Lagrangians with tensor sources

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    The implementation of tensor sources in Chiral Lagrangians allows the computation of Green functions and form factors involving tensor currents, that is, quark bilinears of the form \bar{q}_i\sigma^{\mu\nu}q_j. Whereas only four new terms show up at O(p^4), we find around a hundred of them at O(p^6). So it becomes essential to ensure that this set o operators is indeed minimal and non-redundant (i.e., it is a basis). We discuss two phenomenological applications in the context of vector meson resonances and the radiative pion decay.Comment: Talk given at the 4th International Worshop on Quantum ChromoDynamics, Theory and experiment, June 16-20, 2007. Martina Franca - Valle d'Itria - Ital

    Spectral-Function Sum Rules in Supersymmetry Breaking Models

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    The technique of Weinberg's spectral-function sum rule is a powerful tool for a study of models in which global symmetry is dynamically broken. It enables us to convert information on the short-distance behavior of a theory to relations among physical quantities which appear in the low-energy picture of the theory. We apply such technique to general supersymmetry breaking models to derive new sum rules.Comment: 18 pages, 1 figur

    Electromagnetic form factors of the (rho) meson in light cone QCD sum rules

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    We investigate the electromagnetic form factors of the (rho) meson in light cone QCD sum rules. We find that the ratio of the magnetic and charge form factors is larger than two at all values of Q^2, (Q^2 >= 0.5 GeV^2). The values of the individual form factors at fixed values of Q^2 predicted by the light cone QCD sum rules are quite different compared to the results of other approaches. These results can be checked in future, when more precise data on (rho) meson form factors is available.Comment: 12 pages, 6 figures, LaTeX formatte

    The electromagnetic effects in Ke4K_{e4} decay

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    The final state interaction of pions in Ke4K_{e4} decay allows one to obtain the value of the isospin and angular momentum zero ππ\pi\pi scattering length a00a_0^0.We take into account the electromagnetic interaction of pions and isospin symmetry breaking effects caused by different masses of neutral and charged pions and estimate the impact of these effects on the procedure of scattering length extraction from Ke4K_{e4} decay.Comment: 8 pages,1 figur

    The isospin symmetry breaking effects in Ke4K_{e4} decays

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    The Fermi-Watson theorem is generalized to the case of two coupled channels with different masses and applied to final state interaction in Ke4K_{e4} decays. The impact of considered effect on the phase of the ππ\pi\pi scattering is estimated and shown that it can be crucial for scattering lengths extraction from experimental data on Ke4K_{e4} decays
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