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473 results on '"Helayël-Neto, J."'

234. DILATONIC, CURRENT-CARRYING COSMIC STRINGS.

Author

FERREIRA, C. N., GUIMARÃES, M. E. X., and HELAYËL-NETO, J. A.

Subjects
COSMIC strings, DILATON, BOSONS, SCALAR field theory, ELECTROMAGNETISM
Published
2000

241. Anomalous g-Factors for Charged Leptons in a Fractional Coarse-Grained Approach.

Author

Weberszpil, J. and Helayël-Neto, J. A.

Subjects
*LEPTONS (Nuclear physics), *PARTICLE size determination, *HELICITY of nuclear particles, *DIRAC equation, *ELECTROMAGNETIC fields
Abstract

We here propose to extend the concept of helicity to include it in a fractional scenario and we write down the left- and the righthanded Weyl equations from first principles in this extended framework. Next, by coupling the different fractional Weyl sectors by means of a mass parameter, we arrive at the fractional version of Dirac's equation which, whenever coupled to an external electromagnetic field and reduced to the nonrelativistic regime, yields a fractional Pauli-type equation. From the latter, we are able to present an explicit expression for the gyromagnetic ratio of charged fermions in terms of the fractionality parameter. We then focus our efforts to relate the coarse-grained property of space-time to fractionality and to the (g - 2) anomalies of the different leptonic species. [ABSTRACT FROM AUTHOR]

Published
2014
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244. Electron-electron bound states in Maxwell-Chern-Simons-Proca QED ... 3.

Author

Belich, H., Del Cima, O. M., Ferreira Jr., M. M., and Helayël-Neto, J. A.

Subjects
ELECTRON-electron interactions, MAXWELL equations, LAGRANGIAN functions, SCATTERING (Physics), PHOTONS, ELECTRONIC excitation
Abstract

Focuses on a version of planar QED3 for which the photonic excitations appear as a by-product of a spontaneous symmetry breaking realized on the Maxwell-Chern-Simons Lagrangian. Description of the QED3 Lagrangian; Evaluation of the amplitudes for Möller scattering; Numerical computation of electron-electron bound states.

Published
2003
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245. Electronic Bound States in Parity-Preserving QED[sub 3] Applied to High-T[sub C] Cuprate Superconductors.

Author

Christiansen, H. R., del Cima, O. M., Ferreira Jr., M. M., and Helayël-Neto, J. A.

Subjects
QUANTUM electrodynamics, ELECTRON-electron interactions, SHEAR waves, SCHRODINGER equation
Abstract

We consider a parity-preserving QED[sub 3] model with spontaneous breaking of the gauge symmetry as a framework for the evaluation of the electron-electron interaction potential underlying high-T[sub c] superconductivity. The fact that the resulting potential, -C[sub s]K[sub 0](Mr), is non-confining and "weak" (in the sense of Kato) strongly suggests the mechanism of pair-condensation. This potential, compatible with an s-wave order parameter, is then applied to the Schrödinger equation for the sake of numerical calculations, thereby enforcing the existence of bound states. The results worked out by means of our theoretical framework are checked by considering a number of phenomenological data extracted from different copper oxide superconductors. The agreement may motivate a deeper analysis of our model viewing an application to quasiplanar cuprate superconductors. The data analyzed here suggest an energy scale of 1-10 meV for the breaking of the U(1)-symmetry. [ABSTRACT FROM AUTHOR]

Published
2003
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246. Electron–Electron Attractive Interaction in Maxwell–Chern–Simons QED[sub 3] at Zero Temperature.

Author

Belich, H., Cima, O. M. Del, Ferreira JR., M. M., and Helayël-Neto, J. A.

Subjects
ELECTRON-electron interactions, GAUGE field theory
Abstract

One discusses the issue of low-energy electron-electron bound states in the MaxwellChern-Simons model coupled to QED[sub 3] with spontaneous breaking of a local U(1)symmetry. The scattering potential, in the nonrelativistic limit, stemming from the electron-electron Møller scattering, mediated by the Maxwell-Chern-Simons-Proca gauge field and the Higgs scalar, might be attractive by properly fine-tuning the physical parameters of the model. [ABSTRACT FROM AUTHOR]

Published
2001
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247. On Massive Vector Bosons and Abelian Magnetic Monopoles in D=(3+1): A Possible Way to Quantize the Topological Mass Parameter.

Author

Moura-Melo, Winder A., Panza, N., and Helayël-Neto, J. A.

Subjects
ABELIAN groups, GAUGE field theory, BOSONS
Abstract

An Abelian gauge model, with vector and two-form potential fields linked by a topological mass term mixing the two Abelian factors, is shown to exhibit Dirac-like magnetic monopoles in the presence of a matter background. In addition, considering a "nonminimal coupling" between the fermions and the tensor fields, we obtain a generalized quantization condition that involves, among others, the topological mass parameter. Also, it is explicitly shown that one-loop (finite) corrections do not shift the value of such a mass parameter. [ABSTRACT FROM AUTHOR]

Published
1999
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248. Broken N = 4 yang-mills theory: 2-loop finiteness.

Author

Helayël-Neto, J.

Abstract

Copyright of Il Nuovo Cimento: A is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
1984
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249. N=2 Maxwell–Chern–Simons Model with Anomalous Magnetic Moment Coupling Via Dimensional Reduction.

Author

Christiansen, H. R., Cunha, M. S., Helayël-Neto, J. A., Manssur, L. R. U., and Nogueira, A. L. M. A.

Subjects
SUPERSYMMETRY, MATTER, GAUGE field theory
Abstract

An N = 1-supersymmetric version of the Cremmer-Scherk-Kalb-Ramond model with nonminimal coupling to matter is built up both in terms of superfields and in a component-field formalism. By adopting a dimensional reduction procedure, the (N = 2)-(D = 3) counterpart of the model comes out, with two main features: a genuine (diagonal) Chern-Simons term and an anomalous magnetic moment coupling between matter and the gauge potential. [ABSTRACT FROM AUTHOR]

Published
1999
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