Probing negative-dimensional integration: Two-loop covariant vertex and one-loop light-cone integrals

The negative-dimensional integration method (NDIM) seems to be a very promising technique for evaluating massless and/or massive Feynman diagrams. It is unique in the sense that the method gives solutions in different regions of external momenta simultaneously. Moreover, it is a technique whereby the difficulties associated with performing parametric integrals in the standard approach are transferred to a simpler solving of a system of linear algebraic equations, thanks to the polynomial character of the relevant integrands. We employ this method to evaluate a scalar integral for a massless two-loop three-point vertex with all the external legs off-shell, and consider several special cases for it, yielding results, even for distinct simpler diagrams. We also consider the possibility of NDIM in non-covariant gauges such as the light-cone gauge and do some illustrative calculations, showing that for one-degree violation of covariance (i.e. one external, gauge-breaking, light-like vector n μ) the ensuing results are concordant with the ones obtained via either the usual dimensional regularization technique, or the use of the principal value prescription for the gauge-dependent pole, while for two-degree violation of covariance - i.e. two external, light-like vectors n μ, the gauge-breaking one, and (its dual) n * μ - the ensuing results are concordant with the ones obtained via causal constraints or the use of the so-called generalized Mandelstam-Leibbrandt prescription. © 1999 Elsevier Science B.V.

Desempenho e Digestibilidade in vivo de Cordeiros Alimentados com Dietas Contendo Canola em Grão Integral em Diferentes Formas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Quantum propagator for some classes of three-dimensional three-body systems

In this work we solve exactly a class of three-body propagators for the most general quadratic interactions in the coordinates, for arbitrary masses and couplings. This is done both for the constant as the time-dependent couplings and masses, by using the Feynman path integral formalism. Finally, the energy spectrum and the eigenfunctions are recovered from the propagators. © 2005 Elsevier Inc. All rights reserved.

Evaluating residues and integrals through negative dimensional integration method (NDIM)

The standard way of evaluating residues and some real integrals through the residue theorem (Cauchy's theorem) is well-known and widely applied in many branches of Physics. Herein we present an alternative technique based on the negative dimensional integration method (NDIM) originally developed to handle Feynman integrals. The advantage of this new technique is that we need only to apply Gaussian integration and solve systems of linear algebraic equations, with no need to determine the poles themselves or their residues, as well as obtaining a whole class of results for differing orders of poles simultaneously.

Hacia un nuevo pacto social: políticas económicas para un desarrollo integral en América Latina

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Experiencias del programa de desarrollo rural integral silvo-agropecuario de Cajamarca-Perú

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Envejecimiento en América Latina: sistemas de pensiones y protección social integral

Prólogo de Alicia Bárcena

Protección social inclusiva en América Latina : una mirada integral, un enfoque de derechos

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Hacia la revalorización integral del campesinado

Postula que la revalorización de las culturas campesinas debe ser un proceso de la voluntad política, solidario, y componente esencial del verdadero desarrollo.

La gestión integral de peticiones clínicas en el ámbito de la salud electrónica

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Estrategia municipal para la intervención integral de asentamientos humanos espontáneos de Managua, Nicaragua

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Desarrollo de un Sistema de Información Integral de de Salud Intercultural (SIISI): Rakin Mongen Filu Lawen Pu che

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Sistemas nacionales de protección integral de la infancia: fundamentos jurídicos y estado de aplicación en América Latina y el Caribe

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