5,083 research outputs found

    Hadronic spectra in AdS / QCD correspondence

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    We present an holographical soft wall model which is able to reproduce Regge spectra for hadrons with an arbitrary number of constituents. The model includes the anomalous dimension of operators that create hadrons, together with a dilaton, whose form is suggested by Einstein`s equations and the AdS metricComment: 4 pages, 2 figures, to appear in the Proceedings of the VIII Latin American Symposium on Nuclear Physics and Applications, Santiago, Chile, 15-19 December 2009. Talk presented by A.

    Relation between Lepton Flavor Violating Processes

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    We demonstrate the existence of model independent one-to-one correspondence relations between different lepton flavor violating processes (LFV). Applying the criterion of naturalness, based on the idea of "custodial symmetry", we show that all the LFV processes, independently of specific mechanisms behind them, but with the same external leptons, have a priori comparable amplitudes modulo their kinematics and involved form factors.Comment: 9 pages, 1 figure. An illustrative example and some references adde

    Orbital structure of quarks inside the nucleon in the light-cone diquark model

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    We study the orbital angular momentum structure of the quarks inside the proton. By employing the light-cone diquark model and the overlap representation formalism, we calculate the chiral-even generalized parton distribution functions (GPDs) Hq(x,ξ,Δ2)H_q(x,\xi,\Delta^2), H~q(x,ξ,Δ2)\widetilde{H}_q(x,\xi,\Delta^2) and Eq(x,ξ,Δ2)E_q(x,\xi,\Delta^2) at zero skewedness for q=uq=u and dd quarks. In our model EuE_u and EdE_d have opposite sign with similar size. Those GPDs are applied to calculate the orbital angular momentum (OAM) distributions, showing that Lu(x)L_u(x) is positive, while Ld(x)L_d(x) is consistent with zero compared with Lu(x)L_u(x). We introduce the impact parameter dependence of the quark OAM distribution. It describes the position space distribution of the quark orbital angular momentum at given xx. We found that the impact parameter dependence of the quark OAM distribution is axially symmetric in the light-cone diquark model.Comment: 15 pages, 6 figure
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