10,105 research outputs found

    The standard electroweak model in the noncommutative DFRDFR space-time

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    The noncommutative (NC) framework elaborated by Doplicher, Fredenhagen and Roberts (DFR) has a Lorentz invariant spacetime structure in order to be considered as a candidate to understand the physics of the early Universe. In DFR formalism the NC parameter (θμν\theta^{\mu\nu}) is a coordinate operator in an extended Hilbert space and it has a conjugate momentum. Since xx and θμν\theta^{\mu\nu} are independent coordinates, the Weyl-Moyal (WM) product can be used in this framework. With these elements, in this work, we have constructed the standard electroweak model. To accomplish this task we have begun with the WM-product basis group of symmetry. After that we have introduced the spontaneous symmetry breaking and the hypercharge in DFR framework. The electroweak symmetry breaking was analyzed and the masses of the new bosons were computed. Finally, the gauge symmetry and gauge transformations were discussed.Comment: arXiv admin note: text overlap with arXiv:1506.00035, arXiv:1510.0835

    The Yang-Mills gauge theory in DFR noncommutative space-time

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    The Doplicher-Fredenhagen-Roberts (DFR) framework for noncommutative (NC) space-times is considered as an alternative approach to describe the physics of quantum gravity, for instance. In this formalism, the NC parameter, {\it i.e.} θμν\theta^{\mu\nu}, is promoted to a coordinate of a new extended space-time. Consequently, we have a field theory in a space-time with spatial extra-dimensions. This new coordinate has a canonical momentum associated, where the effects of a new physics can emerge in the fields propagation along the extra-dimension. In this paper we introduce the gauge invariance in the DFR NC space-time. We present the non-Abelian gauge symmetry in DFR formalism, and the consequences of this symmetry in the presence of such extra-dimension. The gauge symmetry in this DFR scenario can reveal new fields attached to θ\theta-extra-dimension. We obtain the propagation of these gauge fields in terms of canonical momentum associated with θ\theta-coordinate.Comment: 26 page

    An alternative way to explain how non-commutativity arises in the bosonic string theory

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    In this work we will investigate how the non-commutativity arises into the string theory, \textit{i.e.}, how the bosonic string theory attaches to a D3-brane in the presence of magnetic fields. In order to accomplish the proposal, we departure from the commutative two-dimensional harmonic oscillator, which after the application of the general Bopp's shifts Matrix Method, the non-commutative version of the two-dimensional harmonic oscillator is obtained. After that, this non-commutative harmonic oscillator will be mapped into the bosonic string theory in the light cone frame, which it now appears as a bosonic string theory attached to a D3-brane

    Noncommutative approach to diagnose degenerate Higgs bosons at 125 GeV

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    We propose a noncommutative (NC) version for a global O(2) scalar field theory, whose damping feature is introduced into the scalar field theory through the NC parameter. In this context, we investigate how noncommutative drives spontaneous symmetry breaking (SSB) and Higgs-Kibble mechanisms and how the damping feature workout. Indeed, we show that the noncommutativity plays an important role in such mechanisms, i.e., the Higgs mass and VEV dependent on NC parameter. After that, it is explored the consequences of noncommutativity dependence of Higgs mass and VEV: for the first, it is shown that there are a mass-degenerate Higgs bosons near 126.5 GeV, parametrized by the noncommutativity; for the second, the gauge fields gain masses that present a noncommutativity contribution.Comment: 13 pages, 2 figure

    Noncommutative Mapping from the symplectic formalism

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    The Bopp's shifts will be generalized through symplectic formalism. A special procedure, like a "diagonalization", which drives the completely deformed symplectic matrix to the standard symplectic form was found as suggested by Faddeev-Jackiw. Consequently, the correspondent transformation matrix guides the mapping from commutative to noncommutative (NC) phase-space coordinates. The Bopp's shifts may be directly generalized from this mapping. In this context, all the NC and scale parameters, introduced into the brackets, will be lifted to the Hamiltonian. Well known results, obtained using ⋆\star-product, will be reproduced without to consider that the NC parameters are small(<<1)(<<1). Besides, it will be shown that different choices for NC algebra among the symplectic variables generates distinct dynamical systems, which they may not even connect with each other, and that some of them can preserve, break or restore the symmetry of the system. Further, we will also discuss the charge and mass rescaling in a simple model.Comment: 24 page

    Noncommutative approach to disclose a Higgs group

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    A noncommutative(NC) version for a global O(N)O(N) scalar field theory is proposed and an alternative investigation about how noncommutative drives spontaneous symmetry breaking (SSB) is explored. Indeed, we show that the noncommutativity plays an important role in such mechanism, i.e., it is possible to show that there is a Higgs group with no more than two Higgs bosons. In this scenario, we establish two mutually exclusive options: one Higgs boson with mass at 125 GeV and other at 750 GeV -- 2 TeV excess does not imply a 2 TeV mass resonance -- or two Higgs bosons with mass-degenerate near 125~GeV, where 2 TeV and 750 GeV excesses do not imply a 2 TeV and 750 GeV masses resonance.Comment: arXiv admin note: text overlap with arXiv:1903.0972

    ON THE COVARIANTIZATION OF THE CHIRAL CONSTRAINT

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    We show that a complete covariantization of the chiral constraint in the Floreanini-Jackiw necessitates an infinite number of auxiliary Wess-Zumino fields otherwise the covariantization is only partial and unable to remove the nonlocality in the chiral boson operator. We comment on recent works that claim to obtain covariantization through the use of Batalin-Fradkin-Tyutin method, that uses just one Wess-Zumino field.Comment: Latex, 10 pages, no figure

    The protophobic XX-boson coupled to quantum electrodynamics

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    The possible origin of an XX-boson having a mass value around 17 \, \mbox{MeV} had motivated us to investigate its interaction with leptons of QED. This new hypothetical particle can possibly be a candidate to describe the so called fifth interaction, in a new physics scenario beyond the Standard Model. The model of the XX-boson interacting with QED is based on a U(1)×U′(1)U(1) \times U'(1) symmetry, where the group U′(1)U'(1) is attached to the XX-boson, with a kinetic mixing with the photon. The Higgs sector was revisited to generate the mass for the new boson. Thus, the mass of 17 \, \mbox{MeV} fixes a vacuum expected value scale. Thereby, we could estimate the mass of the hidden Higgs field through both the VEV-scale and the Higgs' couplings. A model of QFT was constructed in a renormalizable gauge, and we analyzed its perturbative structure. After that, the radiative correction of the XX-boson propagator has been calculated at one loop approximation to yield the Yukawa potential correction. The form factors associated with the QED-vertex correction were calculated to confirm electron's anomalous magnetic moment together with the computation of the interaction magnitude. The muon case was discussed. Furthermore, we have introduced a renormalization group scheme to explore the current XX-boson mass and its coupling constant with the leptons of the Standard Model.Comment: 13 pages, 2 figure

    Path integral formalism in a Lorentz invariant noncommutative space

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    We introduced a new formulation for the path integral formalism for a noncommutative (NC) quantum mechanics defined in the recently developed Doplicher-Fredenhagen-Roberts-Amorim (DFRA) NC framework that can be considered an alternative framework for the NC spacetime of the early Universe. The operators formalism was revisited and we apply its properties to obtain a NC transition amplitude representation. Two DFRA's systems were discussed, the NC free particle and NC harmonic oscillator. Some temperature concepts in this NC space are also considered. The extension to NC DFRA quantum field theory is straightforward and we apply it to a massive scalar field. We construct the generating functional and the effective action to give rise one-particle-irreducible diagrams. As an example, we set the basis for a n  (n≥3)n\;(n\geq 3) self-interaction ϕn\phi^{n} to obtain the correction of the perturbation theory to the propagator and vertex of this model. The main concept that we would like to emphasize from the outset is that the formalism demonstrated here will not be constructed introducing a NC parameter in the system, as usual. It will be generated naturally from an already NC space. In this extra dimensional NC space, we presented also the idea of dimensional reduction to recover commutativity.Comment: 21 pages. Pre-print style. Comments welcom

    Some aspects of quantum mechanics and field theory in a Lorentz invariant noncommutative space

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    We obtained the Feynman propagators for a noncommutative (NC) quantum mechanics defined in the recently developed Doplicher-Fredenhagen-Roberts-Amorim (DFRA) NC background that can be considered as an alternative framework for the NC spacetime of the early Universe. The operators formalism was revisited and we applied its properties to obtain a NC transition amplitude representation. Two examples of DFRA's systems were discussed, namely, the NC free particle and NC harmonic oscillator. The spectral representation of the propagator gave us the NC wave function and energy spectrum. We calculated the partition function of the NC harmonic oscillator and the distribution function. Besides, the extension to NC DFRA quantum field theory is straightforward and we used it in a massive scalar field. We had written the scalar action with self-interaction Ï•4\phi^{4} using the Weyl-Moyal product to obtain the propagator and vertex of this model needed to perturbation theory. %and the effective action to give rise one-particle-irreducible diagrams. It is important to emphasize from the outset is that the formalism demonstrated here will not be constructed introducing a NC parameter in the system, as usual. It will be generated naturally from an already NC space. In this extra dimensional NC space, we presented also the idea of dimensional reduction to recover commutativity.Comment: 22 pages. Continuation of 1206.4065 with substantial text overlap. arXiv admin note: substantial text overlap with arXiv:1206.406
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