16,276 research outputs found

    Renormalization programme for effective theories

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    We summarize our latest developments in perturbative treating the effective theories of strong interactions. We discuss the principles of constructing the mathematically correct expressions for the S-matrix elements at a given loop order and briefly review the renormalization procedure. This talk shall provide the philosophical basement as well as serve as an introduction for the material presented at this conference by A. Vereshagin and K. Semenov-Tian-Shansky.Comment: 6 pages, talk given at HSQCD 2004, Russia, May 2004, to be published in Proceeding

    Bootstrap and the Parameters of Pion-Nucleon Resonances

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    In this talk we demonstrate the results of application of the perturbative effective theory formalism developed in recent papers to the calculation of πN\pi N elastic scattering amplitude. Restrictions on the contributing resonance parameters are obtained and the low energy coefficients are calculated.Comment: 6 pages, talk given at the X. International Conference On Hadron Spectroscopy (HADRON'03), August 31 - September 6, 2003, Aschaffenburg, Germany; to appear in Proceeding

    Localizable Effective Theories, Bootstrap and the Parameters of Hadron Resonances

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    We discuss the basic principles of constructing a meaningful perturbative scheme for effective theory. The main goal of this talk is to explain the approach and to present recent results obtained with the help of the method of Cauchy forms in several complex variables.Comment: 6 pages, Talk given at the X. International Conference On Hadron spectroscopy (HADRON'03), August 31 - September 6, 2003, Aschaffenburg, Germany; to appear in Proceeding

    Bootstrap and the physical values of πN\pi N resonance parameters

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    This is the 6th paper in the series developing the formalism to manage the effective scattering theory of strong interactions. Relying on the theoretical scheme suggested in our previous publications we concentrate here on the practical aspect and apply our technique to the elastic pion-nucleon scattering amplitude. We test numerically the pion-nucleon spectrum sum rules that follow from the tree level bootstrap constraints. We show how these constraints can be used to estimate the tensor and vector NNρNN\rho coupling constants. At last, we demonstrate that the tree-level low energy expansion coefficients computed in the framework of our approach show nice agreement with known experimental data. These results allow us to claim that the extended perturbation scheme is quite reasonable from the computational point of view.Comment: 41 pages, 7 figure

    A consistent model for \pi N transition distribution amplitudes and backward pion electroproduction

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    The extension of the concept of generalized parton distributions leads to the introduction of baryon to meson transition distribution amplitudes (TDAs), non-diagonal matrix elements of the nonlocal three quark operator between a nucleon and a meson state. We present a general framework for modelling nucleon to pion (πN\pi N) TDAs. Our main tool is the spectral representation for \pi N TDAs in terms of quadruple distributions. We propose a factorized Ansatz for quadruple distributions with input from the soft-pion theorem for \pi N TDAs. The spectral representation is complemented with a D-term like contribution from the nucleon exchange in the cross channel. We then study backward pion electroproduction in the QCD collinear factorization approach in which the non-perturbative part of the amplitude involves \pi N TDAs. Within our two component model for \pi N TDAs we update previous leading-twist estimates of the unpolarized cross section. Finally, we compute the transverse target single spin asymmetry as a function of skewness. We find it to be sizable in the valence region and sensitive to the phenomenological input of our \pi N TDA model.Comment: 39 pages, 9 figure

    The Structure on Invariant Measures of C1C^1 generic diffeomorphisms

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    Let Λ\Lambda be an isolated non-trival transitive set of a C1C^1 generic diffeomorphism f\in\Diff(M). We show that the space of invariant measures supported on Λ\Lambda coincides with the space of accumulation measures of time averages on one orbit. Moreover, the set of points having this property is residual in Λ\Lambda (which implies the set of irregular+^+ points is also residual in Λ\Lambda). As an application, we show that the non-uniform hyperbolicity of irregular+^+ points in Λ\Lambda with totally 0 measure (resp., the non-uniform hyperbolicity of a generic subset in Λ\Lambda) determines the uniform hyperbolicity of Λ\Lambda

    Worldsheet boundary conditions in Poisson-Lie T-duality

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    We apply canonical Poisson-Lie T-duality transformations to bosonic open string worldsheet boundary conditions, showing that the form of these conditions is invariant at the classical level, and therefore they are compatible with Poisson-Lie T-duality. In particular the conditions for conformal invariance are automatically preserved, rendering also the dual model conformal. The boundary conditions are defined in terms of a gluing matrix which encodes the properties of D-branes, and we derive the duality map for this matrix. We demonstrate explicitly the implications of this map for D-branes in two non-Abelian Drinfel'd doubles.Comment: 20 pages, Latex; v2: typos and wording corrected, references added; v3: three-dimensional example added, reference added, discussion clarified, published versio

    Multiparametric Spectroscopic Photoacoustic Imaging of Breast Cancer Development in a Transgenic Mouse Model

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    licenses/by-nc-nd/3.0/). Reproduction is permitted for personal, noncommercial use, provided that the article is in whole, unmodified, and properly cited. Received: 2014.06.16; Accepted: 2014.07.29; Published: 2014.08.15 Objective: To evaluate the potential of multiparametric spectroscopic photoacoustic imaging using oxygen saturation, total hemoglobin, and lipid content to differentiate among four different breast histologies (normal, hyperplasia, ductal carcinoma in situ (DCIS), and invasive breast carcinoma) in a transgenic mouse model of breast cancer development. Materials and Methods: Animal studies were approved by the Institutional Administrative Panel on Laboratory Animal Care. Mammary glands (n=251) of a transgenic mouse model of breast cancer development (FVB/N-Tg(MMTV-PyMT)634Mul) were imaged using B-mode ultrasound and spectroscopic photoacoustic imaging, analyzed for oxygen saturation, total hemoglobin, and lipid content, and processed for histological analysis. Statistical analysis was performed using one-way ANOVA, two-sample t-tests, logistic regression, and ROC analysis. Results: Eighty-two normal, 12 hyperplastic, 96 DCIS, and 61 invasive breast carcinoma mammary glands were analyzed. Based on spectroscopic photoacoustic imaging, the oxygen saturation o

    A mesoscopic ring as a XNOR gate: An exact result

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    We describe XNOR gate response in a mesoscopic ring threaded by a magnetic flux ϕ\phi. The ring is attached symmetrically to two semi-infinite one-dimensional metallic electrodes and two gate voltages, viz, VaV_a and VbV_b, are applied in one arm of the ring which are treated as the inputs of the XNOR gate. The calculations are based on the tight-binding model and the Green's function method, which numerically compute the conductance-energy and current-voltage characteristics as functions of the ring-to-electrode coupling strength, magnetic flux and gate voltages. Our theoretical study shows that, for a particular value of ϕ\phi (=ϕ0/2=\phi_0/2) (ϕ0=ch/e\phi_0=ch/e, the elementary flux-quantum), a high output current (1) (in the logical sense) appears if both the two inputs to the gate are the same, while if one but not both inputs are high (1), a low output current (0) results. It clearly exhibits the XNOR gate behavior and this aspect may be utilized in designing an electronic logic gate.Comment: 8 pages, 5 figure
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