We examine the electromagnetic radiation produced by a moving charge in the QED vacuum that behaves as a dispersive medium characterized by a geometrical structure (discreteness/granularity) that emerges from loop quantum gravity. It is shown that the radiation is driven by the refractive vacuum the charged particle travels through reproducing the profile of the Cherenkov effect.

Chile

Patricio Gaete

Brazil

J.A. Helayël-Neto

Gambini-Pullin electrodynamics as a scenario for Cherenkov radiation in QED vacuum

We address the effect of an anomalous triple gauge boson couplings on a physical observable for the electroweak sector of the Standard Model, when the <math id="M1"><mi>S</mi><mi>U</mi><msub><mrow><mfenced><mrow><mn>2</mn></mrow></mfenced></mrow><mrow><mi>L</mi></mrow></msub><mo>⊗</mo><mi>U</mi><msub><mrow><mfenced><mrow><mn>1</mn></mrow></mfenced></mrow><mrow><mi>Y</mi></mrow></msub></math> symmetry is spontaneously broken by the Higgs mechanism to <math id="M2"><mi>U</mi><msub><mrow><mfenced><mrow><mn>1</mn></mrow></mfenced></mrow><mrow><mi>e</mi><mi>m</mi></mrow></msub></math>. Our calculation is done within the framework of the gauge-invariant, but path-dependent variable formalism is an alternative to the Wilson loop approach. Our result shows that the interaction energy is the sum of a Yukawa and a linear potential, leading to the confinement of static probe charges. The point we wish to emphasize, however, is that the anomalous triple gauge boson couplings (<math id="M3"><mi>Z</mi><mi>γ</mi><mi>γ</mi></math>) contributes to the confinement for distances on the intranuclear scale.

L.P.R. Ospedal

Remarks on an Anomalous Triple Gauge Boson Couplings

The possible origin of an \(X\)-boson having a mass value around 17 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 simplest \(X\)-boson model unified to the Standard Model is based on an \(\mathrm {SU}_{c}(3) \times \mathrm {SU}_{L}(2) \times \mathrm {U}_{Y}(1) \times \mathrm {U}(1)_{B-L}\) symmetry, where the group \(\mathrm {U}(1)_{B-L}\) is attached to the \(X\)-boson, with a kinetic mixing with the gauge field of \(\mathrm {U}_{Y}(1)\). The Higgs sector was revisited to generate the mass for the new boson. Thus, the mass of 17 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 \(R_{\xi }\)-gauge, and we analyze its perturbative structure. After that, the radiative correction of the \(X\)-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 the 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 running \(X\)-boson mass and its coupling constant with the leptons of the Standard Model.

United States

M.J. Neves

E.M.C. Abreu

The Protophobic \(X\)-boson Coupled to Quantum Electrodynamics

The excitations referred to as oscillons are long-lived time-dependent field configurations which emerge dynamically from non-linear field theories. Such long-lived solutions are of interest in applications that include systems of Condensed Matter Physics, the Standard Model of Particle Physics, Lorentz-symmetry violating scenarios and Cosmology. In this work, we show how oscillons may be accommodated in a supersymmetric scenario. We adopt as our framework simple (<math><mi>N</mi><mo>=</mo><mn>1</mn></math>) supersymmetry in <math><mi>D</mi><mo>=</mo><mn>1</mn><mo>+</mo><mn>1</mn></math> dimensions. We focus on the bosonic sector with oscillon configurations and their (classical) effects on the corresponding fermionic modes, (supersymmetric) partners of the oscillons. The particular model we adopt to pursue our investigation displays cubic superfield which, in the physical scalar sector, corresponds to the usual quartic self-coupling.

R.A.C. Correa

W. de Paula

Supersymmetry and fermionic modes in an oscillon background

It is our aim to show that the Chern-Simons terms of modified gravity can be understood as generated by the addition of a 3-dimensional algebraic manifold to an initial 11-dimensional space-time manifold; this builds up an <math id="M1"><mn>11</mn><mo>+</mo><mn>3</mn></math>-dimensional space-time. In this system, firstly, some fields living in the bulk join the fields that live on the 11-dimensional manifold, so that the rank of the gauge fields exceeds the dimension of the algebra; consequently, there emerges an anomaly. To solve this problem, another 11-dimensional manifold is included in the <math id="M2"><mn>11</mn><mo>+</mo><mn>3</mn></math>-dimensional space-time, and it interacts with the initial manifold by exchanging Chern-Simon fields. This mechanism is able to remove the anomaly. Chern-Simons terms actually produce an extra manifold in the pair of 11-dimensional manifolds of the <math id="M3"><mn>11</mn><mo>+</mo><mn>3</mn></math>-space-time. Summing up the topology of both the 11-dimensional manifolds and the topology of the exchanged Chern-Simons manifold in the bulk, we conclude that the total topology shrinks to one, which is in agreement with the main idea of the Big Bang theory.

Iran

Alireza Sepehri

Tooraj Ghaffary

The Origin of Chern-Simons Modified Gravity from an 11 + 3-Dimensional Manifold

Germany

P.C. Malta

K. Veiga

Corrigendum to “Comparative Aspects of Spin-Dependent Interaction Potentials for Spin-1/2 and Spin-1 Matter Fields”

This paper sets out to establish a comparative study between classes of spin- and velocity-dependent potentials for spin-1/2 and spin-1 matter currents/sources in the nonrelativistic regime. Both (neutral massive) scalar and vector particles are considered to mediate the interactions between (pseudo-)scalar sources or (pseudo-)vector currents. Though our discussion is more general, we contemplate specific cases in which our results may describe the electromagnetic interaction with a massive (Proca-type) photon exchanged between two spin-1/2 or two spin-1 carriers. We highlight the similarities and peculiarities of the potentials for the two different types of charged matter and also focus our attention on the comparison between the particular aspects of two different field representations for spin-1 matter particles. We believe that our results may contribute to a further discussion of the relation between charge, spin, and extensibility of elementary particles.

Comparative Aspects of Spin-Dependent Interaction Potentials for Spin-1/2 and Spin-1 Matter Fields

We here propose a 5-dimensional Abelian gauge model based on the mixing between a U (1) potential and an Abelian 3-form field by means of a topological mass term. An extended covariant derivative is introduced to minimally couple a Dirac field to the U (1) potential, while this same covariant derivative non-minimally couples the 3-form field to the charged fermion. A number of properties are discussed in 5D; in particular, the appearance of a topological fermionic current. A 4-dimensional reduced version of the model is investigated and, in addition to the U (1) electric- and magnetic-sort of fields, there emerges an extra set of electric- and magnetic-like fields which contribute a negative pressure and may be identified as a possible fraction of dark energy. The role of the topological fermionic current is also contemplated upon dimensional reduction from 5D to 4D. Other issues we present in 4 space-time dimensions are the emergence of a pseudo-scalar massive particle, an extra massive neutral gauge boson, which we interpret as a kind of paraphoton, and the calculation of spin- and velocity-dependent interparticle potentials associated to the exchange of the intermediate bosonic fields of the model.

D. Cocuroci

A 3-form gauge potential in 5D in connection with a possible dark sector of 4D-electrodynamics

Background fermion condensates in a landscape dominated by global supersymmetry are reassessed in connection with a scenario where Lorentz symmetry is violated in the bosonic sector (actually, the photon sector) by a CPT-even kF term. An effective photonic action is discussed that originates from the supersymmetric background fermion condensates. Also, the photino mass emerges in terms of a particular condensate contrary to what happens in the case of kAF -violation. Finally, the interparticle potential induced by the effective photonic action is investigated and a confining profile is identified.

H. Belich

L.D. Bernald

F.J.L. Leal

Aspects of CPT-even Lorentz-symmetry violating physics in a supersymmetric scenario

We investigate the role played by particular field representations of an intermediate massive spin-1 boson in the context of spin-dependent interparticle potentials between fermionic sources in the limit of low momentum transfer. The comparison between the well-known case of the Proca field and that of an exchanged spin-1 boson (with gauge-invariant mass) described by a 2-form potential mixed with a 4-vector gauge field is established in order to pursue an analysis of spin- as well as velocity-dependent profiles of the interparticle potentials. We discuss possible applications and derive an upper bound on the product of vector and pseudo-tensor coupling constants.