31,027 research outputs found

    Nonet meson properties in Nambu--Jona-Lasinio model with dimensional versus cutoff regularization

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    Nambu--Jona-Lasinio (NJL) model with Kobayashi-Maskawa-'t Hooft (KMT) term is one of low energy effective theory of QCD which includes the UA(1)U_A(1) anomaly. We investigate nonet meson properties in this model with three flavors of quarks. We employ two type of regularizations the dimensional and sharp cutoff ones. The model parameters are fixed phenomenologically for each regularization. Evaluating the kaon decay constant, the η\eta meson mass and the topological susceptibility, we show the regularization dependence of the results and discuss the applicability of the NJL model.Comment: 11 pages, 9 figure

    Phonon engineering with superlattices: generalized nanomechanical potentials

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    Earlier implementations to simulate coherent wave propagation in one-dimensional potentials using acoustic phonons with gigahertz-terahertz frequencies were based on coupled nanoacoustic resonators. Here, we generalize the concept of adiabatic tuning of periodic superlattices for the implementation of effective one-dimensional potentials giving access to cases that cannot be realized by previously reported phonon engineering approaches, in particular the acoustic simulation of electrons and holes in a quantum well or a double well potential. In addition, the resulting structures are much more compact and hence experimentally feasible. We demonstrate that potential landscapes can be tailored with great versatility in these multilayered devices, apply this general method to the cases of parabolic, Morse and double-well potentials and study the resulting stationary phonon modes. The phonon cavities and potentials presented in this work could be probed by all-optical techniques like pump-probe coherent phonon generation and Brillouin scattering

    Color Superconductivity and Radius of Quark Star in Extended NJL Model by Using the Dimensional Regularization

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    A radius of a dense star on the color superconducting phase is investigated in an extended NJL type model with two flavors of quarks. Since the model is non-renormalizable, the results depend on the regularization procedure. Here we apply the dimensional regularization and evaluate the radius of a dense star. Evaluating the TOV equation, we show the relationship between mass and radius of the dense star in the dimensional regularization.Comment: 4 pages.To appear in the proceedings of 7th Workshop on Quantum Field Theory Under the Influence of External Conditions (QFEXT 05), Barcelona, Catalonia, Spain, 5-9 Sep 2005. References are ad

    Influence of QED Corrections on the Orientation of Chiral Symmetry Breaking in the NJL model

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    We study QED corrections to chiral symmetry breaking in the Nambu--Jona-Lasinio (NJL) model with two flavors of quarks. In this model, the isospin symmetry is broken by the differences between the current quark masses and the electromagnetic charges of the up and down quarks. To leading order in the 1/N expansion, we calculate the effective potential of the model with one-loop QED corrections at finite temperature. Evaluating the effective potential, we study the influence of the isospin symmetry breaking on the orientation of chiral symmetry breaking. The current quark mass plays an essential role in maintaining the orientation of the chiral symmetry breaking. If the average of the up and down quark masses is small enough, we find a phase in which the pion field has non-vanishing expectation value and dynamical CP violation takes place.Comment: 22 pages, 13 figures; added discussion about pion mass differenc

    Canonical Quantization of SU(3) Skyrme Model in a General Representation

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    A complete canonical quantization of the SU(3) Skyrme model performed in the collective coordinate formalism in general irreducible representations. In the case of SU(3) the model differs qualitatively in different representations. The Wess-Zumino-Witten term vanishes in all self-adjoint representations in the collective coordinate method for separation of space and time variables. The canonical quantization generates representation dependent quantum mass corrections, which can stabilize the soliton solution. The standard symmetry breaking mass term, which in general leads to representation mixing, degenerates to the SU(2) form in all self-adjoint representations.Comment: 24 RevTex4 pages, no figure

    SpecPro: An Interactive IDL Program for Viewing and Analyzing Astronomical Spectra

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    We present an interactive IDL program for viewing and analyzing astronomical spectra in the context of modern imaging surveys. SpecPro's interactive design lets the user simultaneously view spectroscopic, photometric, and imaging data, allowing for rapid object classification and redshift determination. The spectroscopic redshift can be determined with automated cross-correlation against a variety of spectral templates or by overlaying common emission and absorption features on the 1-D and 2-D spectra. Stamp images as well as the spectral energy distribution (SED) of a source can be displayed with the interface, with the positions of prominent photometric features indicated on the SED plot. Results can be saved to file from within the interface. In this paper we discuss key program features and provide an overview of the required data formats.Comment: Accepted for publication in the Publications of the Astronomical Society of the Pacific (PASP) journal. Website: specpro.caltech.ed

    Anisotropic Electronic Structure of the Kondo Semiconductor CeFe2Al10 Studied by Optical Conductivity

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    We report temperature-dependent polarized optical conductivity [σ(ω)\sigma(\omega)] spectra of CeFe2_2Al10_{10}, which is a reference material for CeRu2_2Al10_{10} and CeOs2_2Al10_{10} with an anomalous magnetic transition at 28 K. The σ(ω)\sigma(\omega) spectrum along the b-axis differs greatly from that in the acac-plane, indicating that this material has an anisotropic electronic structure. At low temperatures, in all axes, a shoulder structure due to the optical transition across the hybridization gap between the conduction band and the localized 4f4f states, namely cc-ff hybridization, appears at 55 meV. However, the gap opening temperature and the temperature of appearance of the quasiparticle Drude weight are strongly anisotropic indicating the anisotropic Kondo temperature. The strong anisotropic nature in both electronic structure and Kondo temperature is considered to be relevant the anomalous magnetic phase transition in CeRu2_2Al10_{10} and CeOs2_2Al10_{10}.Comment: 5 pages, 4 figure

    Isospin Effects on Astrophysical S-Factors

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    We estimate the ratios of bare astrophysical S-factors at zero incident energy for proton and deuteron induced reactions in a model which assumes a compound nucleus formation probability plus a statistical decay. The obtained ratios agree well with available experimental values, as far as the reactions which have dominant s-wave entrance channel components are investigated. Due to its simplicity the model could be used as a guidance for predictions on reactions which have not been investigated yet.Comment: 12 pages, 1 figure
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