On the nonminimal vector coupling in the Duffin-Kemmer-Petiau theory and the confinement of massive bosons by a linear potential

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

SINGULARITY THEORY and FORCED SYMMETRY BREAKING IN EQUATIONS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Remarks on Duffin-Kemmer-Petiau theory and gauge invariance

Two problems relative to the electromagnetic coupling of Duffin-Kemmer-Petiau (DKP) theory are discussed: the presence of an anomalous term in the Hamiltonian form of the theory and the apparent difference between the interaction terms in DKP and Klein-Gordon (KG) Lagrangians. For this, we first discuss the behavior of DKP field and its physical components under gauge transformations. From this analysis, we can show that these problems simply do not exist if one correctly analyses the physical components of DKP field. (C) 2000 Elsevier B.V. B.V. All rights reserved.

QUARK MEAN-FIELD THEORY AND CONSISTENCY WITH NUCLEAR-MATTER

1/N(c) expansion in QCD (with N(c) the number of colors) suggests using a potential from meson sector (e.g., Richardson) for baryons. For light quarks a sigma-field has to be introduced to ensure chiral symmetry breaking (chi-SB). It is found that nuclear matter properties can be used to pin down the chi-SB modeling. All masses, M(N), m-sigma, m-omega, are found to scale with density. The equations are solved self-consistently.

On the dissimilarity between the algorithms for computing the symmetric energy-momentum tensor in ordinary field theory and general relativity

The recipe used to compute the symmetric energy-momentum tensor in the framework of ordinary field theory bears little resemblance to that used in the context of general relativity, if any. We show that if one stal ts fi om the field equations instead of the Lagrangian density, one obtains a unified algorithm for computing the symmetric energy-momentum tensor in the sense that it can be used for both usual field theory and general relativity.

MESON PROPERTIES FROM A BAG MODEL COMPARED TO LATTICE THEORY AND HEAVY-ION EXPERIMENTS

A bag at temperature (T) with pressure B(T) = B(0)[1 - (T/T(c))4] is shown to be consistent with recent lattice data on the pi and the rho mesons. The limiting temperature, T(l), of the pion bag from the Bekenstein entropy bound is lower than that of other mesons. This agrees with the thermal distribution of pi, K and the rho in heavy ion collisions, which (unlike proton-nucleus or pp data) show a marked difference in T of pion and other mesons in the mid-rapidity region.

The economics of demand-led growth: theory and evidence for Brazil

Includes bibliography

Note on the nonuniqueness of the massive Fierz-Pauli theory and spectator fields

It is possible to show that there are three independent families of models describing a massive spin-2 particle via a rank-2 tensor. One of them contains the massive Fierz-Pauli model, the only case described by a symmetric tensor. The three families have different local symmetries in the massless limit and can not be interconnected by any local field redefinition. We show here, however, that they can be related with the help of a decoupled and nondynamic (spectator) field. The spectator field may be either an antisymmetric tensor B μν=-Bνμ, a vector Aμ or a scalar field φ, corresponding to each of the three families. The addition of the extra field allows us to formulate master actions which interpolate between the symmetric Fierz-Pauli theory and the other models. We argue that massive gravity models based on the Fierz-Pauli theory are not expected to be equivalent to possible local self-interacting theories built up on top of the two new families of massive spin-2 models. The approach used here may be useful to investigate dual (nonsymmetric) formulations of higher-spin particles. © 2013 American Physical Society.

Informe de la Reunión de Expertos sobre Capacitación en Materia de Gestión de Proyectos y Sistemas de Recursos Hídricos = Report of the Expert Meeting on Training in the Management of Water Resources Projects and Systems

Presenta la organización y resumen de los debates de la reunión que tuvo como objetivo discutir los resultados de los estudios de casos sobre oferta y demanda de capacitación en materia de gestión de proyectos y sistemas de recursos hídricos en algunos países de la región.

Agroforestry in the Amazon Basin: practice, theory and limits of a promising land use

Includes bibliography

Democratic theory and women's participation in politics: the Chilean case

Includes bibliography